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AUDITORY SYSTEM FUNCTION IN INDIVIDUALS WITH
WILLIAMS SYNDROME

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AUDITORY SYSTEM FUNCTION IN INDIVIDUALS WITH WILLIAMS
SYNDROME

BY

Yao-Jan Liu, 8.8.

A THESIS
Submitted to
Michigan State University

in partial fulfillment of the requirements
for the degree of

MASTER OF ARTS

Department of Audiology and Speech Sciences

2005

ABSTRACT

AUDITORY SYSTEM FUNCTION IN INDIVIDUALS WITH WILLIAMS
SYNDROME

By
Yao-Jan Liu, B.S.

Hypersensitivity to sounds is a well-known characteristic of individuals with
Williams syndrome (WS); however, auditory system function in individuals with WS has
not yet been thoroughly evaluated. The purpose of this research project was to test
objectively whether individuals with WS are more sensitive to auditory stimulation (have
better-than-normal thresholds). Seven individuals with WS, between the ages of 7 and 43
years, were recruited for the current study. Audiological and physiological status was
examined using air- and bone-conduction thresholds, tympanometry, loudness discomfort
level measures, distortion-product otoacoustic emissions (DPOAEs) and a hyperacusis
questionnaire that was adapted from Klein, Armstrong, Greer, and Brown (1990). The
results of this study revealed that five of the seven individuals with WS showed pure-tone
thresholds poorer than expected when compared to age peers from the general
population. Only one of them had a documented diagnosis of permanent hearing loss
before this study. The empirical evidence presented here not only suggests that reports of
hypersensitivity to sounds do not justify a conclusion that overall hearing is intact or
better than normal in individuals with WS, but also addresses the importance of early

diagnosis of hearing loss in this population.

Copyright by
YAO-J AN LIU
2005

ACKNOWLEDGMENTS

This study was funded by a grant awarded to thesis co-director, Jeffery Marler
(NICHD R03 HD044468). I would like to express my sincere thanks to the co-chairs on
my thesis committee, Dr. Jeffrey Marler and Dr. Jill Elfenbein, for all their support and
their invaluable comments on my drafts. I would also like to thank the other committee
members, Dr. Jerry Punch and Dr. Rachel Fisher. Special gratitude is extended to all the
families who participated in this study, to the support shown by the National Director of
the Williams Syndrome Association, Terry Monkaba, and to Dr. Carolyn Meris for

assistance with subject recruitment.

iv

TABLE OF CONTENTS

LIST OF TABLES .................................................................................. vii
LIST OF FIGURES ................................................................................ viii
CHAPT ER 1
Introduction ............................................................................................ 1
Literature review ...................................................................................... 3
Behavioral assessment of hearing .............................................................. 3
Hyperacusis and otitis media ................................................................... 5
Auditory verbal strengths ........................................................................ 8
Audiological evaluation of individuals with cognitive impairment ..................... 10
Summary ......................................................................................... l4
Rationale for current study ..................................................................... 14
CHAPTER 2
Method ................................................................................................ 16
Participants.................................‘ ...................................................... 16
Procedures ....................................................................................... 17
Pure-tone thresholds ........................................................................ l7
Otoscopy and tympanometry ............................................................. 19
Speech audiometry ......................................................................... 19
Otoacoustic emissions data ................................................................ 20
Loudness discomfort level (LDL) rating ................................................ 21
Hyperacusis questionnaire ................................................................ 23
CHAPTER 3
Results ................................................................................................ 24
Audiological assessment ....................................................................... 24
Otoscopy ......................................................................................... 24
Immitance ........................................................................................ 24
Pure-tone audiometry .......................................................................... 24
Speech audiometry32
Otoacoustic emission data ..................................................................... 34
Test—retest reliability ........................................................................... 38
Loudness discomfort level (LDL) rating .................................................... 41
Hyperacusis questionnaire ..................................................................... 42
Hypersensitivity to sounds .................................................................... 42
Hearing ........................................................................................ 44
Middle ear infection ........................................................................ 44
CHAPTER 4
Discussion ............................................................................................ 45

Audiological assessment ....................................................................... 45

Otoacoustic emission data ..................................................................... 53

Loudness discomfort level (LDL) rating .................................................... 54

Hyperacusis questionnaire ..................................................................... 55

Evaluation procedures .......................................................................... 57

Summary and conclusion ...................................................................... 58
APPENDICES ....................................................................................... 60

APPENDIX A

Hyperacusis Questionnaire .................................................................... 61

APPENDIX B

Individual Data from Immitance Measues ................................................... 65
REFERENCES ....................................................................................... 67

vi

LIST OF TABLES

Table 1. Gender and age data for each participant (M: Male; F: Female). .................. 17

Table 2. Summary of quantitative measures administrated to participants in the current
study. ................................................................................................. 17

Table 3. Data comparison of extended high-frequency air-conduction thresholds obtained
from WSOO4 and mean thresholds for 32 individuals age 20 to 30 years reported by
Stelmachowicz et al. (1989). ...................................................................... 32

Table 4. Speech audiometry and pure-tone-average data for the four adults who
completed the speech audiometry tasks. 33

Table 5. Participant WSOlS’s air-conduction thresholds obtained from hearing screening

and diagnostic evaluation. ......................................................................... 39
Table 6. Loudness discomfort level rating scale data for the adult participants. ........... 41
Table 7. Individual data from immitance measures. ........................................... 66

vii

LIST OF FIGURES

Figure 1. Picture provided for LDL rating measure ............................................ 22

Figure 2. Hearing thresholds for each participant (0: Right ear air-conduction thresholds;
X: Left ear air-conduction thresholds; <: Unmasked right ear bone-conduction thresholds;
>: Unmasked left bone-conduction thresholds; [: Masked right ear bone-conduction

thresholds; ]: Masked left ear bone-conduction thresholds). .................................. 25

Figure 3. Individual DPOAEs for participants WSOO], WSOO2, WSOO3, WSOO4, and
WSOlS. ............................................................................................... 35

Figure 4. DPOAEs of participant WSOIS obtained from hearing screening and diagnostic
evaluation. ........................................................................................... 40

Figure 5. Comparison of the four adult participants’ air-conduction thresholds to expected
median thresholds. The median was calculated from data and formulas provided by ISO
7029-1984 according to each individual’s age and gender (0: Right ear air-conduction
thresholds; X: Left ear air—conduction thresholds; *: Median threshold data calculated
from ISO 7029-1984). .............................................................................. 47

Figure 6. Comparison of the three child participants’ air-conduction thresholds to the
median thresholds reported by Holmes et a1. (1994). The median was selected according
to each participant’s age and gender (0: Right ear air-conduction thresholds; X: Left ear
air-conduction thresholds; *: Median threshold data reported by Holmes et al.). ..........50

viii

CHAPTER 1
Introduction

Williams syndrome (WS), also known as Williams-Beuren syndrome, was
reported by Fanconi (1952), and Williams, Barratt-Boyes, & Lowe (1961). Typical
features of Williams syndrome include specific facial dysmorphology (“elfm” features),
renal and cardiovascular anomalies, failure to thrive in infancy, transient—neonatal
hypercalcemia, elastin arteriopathy, mild-to-moderate mental retardation or learning
difficulties, delayed language and motor development, a unique cognitive profile, a
distinctive personality, and hypersensitivity to speech and abnormal (aversive)
sensitivities to other classes of sounds (Mom's, Demsey, Leonard, Dilts, & Blackburn,
1988; Lenhoff, Wang, Greenberg, & Bellugi, 1997; Bellugi, Lichtenberger, Jones, & Lai,
2000; Morris & Mervis, 2000).

Historically, the incidence of WS has been reported to be at least l/20,000
individuals (Morris et al., 1988). Recently, a Norwegian population prevalence study has
estimated a prevalence closer to 1/7,500 live births (Morris, 2004). The current
understanding of genetic causes of WS involves a micro-deletion of the long arm of
chromosome 7 (Ewart et al. 1993; Korenberg et al., 2000). This micro-deletion includes
gene-encoding elastin (ELN) and 17-20 other genes (Bellugi et al., 2000; DeSilva etal.,
2002; Ewart et al., 1993; Merla, Ucla, Guipponi, & Reymond, 2002; Osborne, 1999) and
can be detected by fluorescent in situ hybridization (FISH) in 99% of individuals with
WS (Lowery et al., 1995).

Relative to their overall level of intellectual ability, individuals with WS typically

show strengths in the areas of phonology (Grant et al., 1997; Volterra, Capirci & Caselli,

2001), auditory (verbal) short-term memory (Grant et al., 1997, Mervis & Klein-Tasman,
2000), and expressive vocabulary (Mervis & Robinson, 2000; Singer-Harris, Bellugi &
Bates, 1997). The relative strengths in phonology and vocabulary have been attributed to
auditory processing strengths (Karmiloff-Smith et al., 1997; Mervis & Klein-Tasman,
2000).

Both auditory verbal strengths (Karmiloff-Smith et al., 1997) and auditory
language comprehension abilities (Neville, Mills, & Bellugi, 1994) of individuals with
WS have been attributed to hypersensitivity to sound. When data collection for this
project was begun, these inferences were supported solely by anecdotal reports of
auditory processing strengths and surprising musical abilities (Lenhoff et al., 1997;
Mervis & Klein-Tasman, 2000) and brief papers and questionnaire-studies reporting high
rates of extreme oversensitivity to sound (Van Borsel, Curfs, & Fryns, 1997; Klein,
Armstrong, Greer and Brown, 1990; O’Reilly, Lacey and Lancioni, 2000; Johnson,
Comeau & Clarke, 2001). Two descriptive studies recounting audiometric performances
of a small number of individuals with WS (Ruangdaraganon, Tocharoentanaphol,
Kotchabhakdi, & Khowsathit, 1999; Johnson et al., 2001) indicated that 33% had
sensorineural hearing loss. These two recent reports of significant rates of hearing loss in
WS are difficult to reconcile with the popular understanding of superior auditory
sensitivity. The literature available provides only a limited foundation for exploring this

inconsistency.

Literature Review

Behavioral assessment of hearing

Audiometric performance in individuals with WS, or those suspected of having
WS (i.e., Nigam & Samuel, 1994), has been reported in three descriptive studies (Nigam
& Samuel, 1994; Ruangdaraganon et al., 1999; Johnson et al., 2001). Nigam and Samuel
(1994) reported a case study of a 21-month-old girl with WS in Sunderland, Britain. She
was seen by a geneticist, and a diagnosis of WS was based on her facial characteristics
rather than on a FISH confirmation. She was referred to an ENT clinic because of
intermittent otalgia, drooling and snoring accompanied by a clear nasal discharge. The
authors reported observation of dull tympanic membranes and collapsed nasal alae, and
that, “on a performance test a 35-40 dB loss was found on the left side and impedance
testing gave a flat trace on the left but normal responses on the right” (p. 494). They also
reported that, six months after adenoidectomy and bilateral myringotomies, her response
to everyday sounds, including the ringing of a doorbell or telephone, was to clasp her
hands over her ears. A follow-up audiologic assessment revealed hearing within normal
limits for both ears.

Ruangdaraganon et al. (1999) reported a case study of two individuals with WS
who were identified by the FISH technique. Participants were a 15-month-old girl and a
16-month-old girl seen in Bangkok, Thailand. Ruangdaraganon et al. reported that one
girl had auditory brainstem responses (ABR) indicative of a bilateral sensorineural
hearing loss. However, they did not report the severity of the hearing loss or the status of
the middle ear function. They did not include otoacoustic emissions measures (OAE) in

their test battery, although a combination of ABR and OAE is commonly used for early

identification of hearing loss. Such data would have provided confirmation of the ABR
results and important information about the site of lesion. For the other participant, they
reported no information concerning hearing assessment or her hearing status.

Johnson et al. (2001) contacted 23 families from the Atlantic Provinces of
Canada. Nine individuals with WS, ages 9 to 25 years, from these families underwent a
full battery of audiologic tests. Their test battery included pure—tone audiometry, speech
recognition thresholds, acoustic reflex thresholds, tympanometry, and transient evoked
otoacoustic emission (TEOAE) measures. Researchers found that sensorineural hearing
loss was present in three participants ages 18, 24, and 25 years within this group. All
three showed moderate sensorineural hearing loss; one had bilateral hearing loss and two
showed unilateral hearing loss. Seven of the nine participants, including these three
participants with sensorineural hearing loss and four participants with normal pure-tone
thresholds, were reported to have absent TEOAEs.

Johnson et al. (2001) failed to define what constituted “normal” hearing
thresholds for a group of adults with mild-to-moderate mental retardation, did not report
speech recognition thresholds, neglected to quantify the magnitude terminology (e. g.,
“moderate”), and did not describe the configuration of the hearing thresholds.
Furthermore, they did not include the pass/fail criterion for the OAE measures. Absent
TEOAEs suggested abnormal outer hair cell function. The absence of TEOAEs in the
individuals with normal hearing (4 of 6 subjects) suggests a lack of sensitivity in the
measurement of hearing loss.

Marler, Elfenbein, Netzloff & Liu (2004) investigated hearing acuity in 21

individuals with WS at the 2004 National Williams Syndrome Conference in Grand

Rapids, Michigan. Fourteen children, ages 7 to 9 years, and seven adults, ages 21 to 48
years, participated in their preliminary study. The test battery included pure-tone, air-
conduction screening at the frequencies of 500, 1,000, 2,000, 4,000, and 8,000 Hz,
screening tympanometry, and DPOAE measures. The criterion for failure of the pure tone
hearing screening was failure to respond to a 20 dB HL signal at any target frequency in
either ear for the adults, and failure to respond to a 15 dB HL signal at any target
frequency in either ear for the children. The criterion for a DPOAE indicative of hearing
loss was an emission below the 5th percentile point for normally hearing ears reported by
Gorga et a1. (1997). One of the adult participants was not included in the analyses
because a second genetic condition (Waardenburg syndrome) was later confirmed.
Sixteen of 20 individuals (80%) with WS in that study showed normal bilateral
tympanograms (Type A). Two more individuals had normal unilateral tympanograms, but
tympanograms could not be obtained on their other ears. No tympanograms were
obtained for two other individuals due to excessive cerumen or complaint of ear pain.
Marler et al. reported that 84% of their participants failed the hearing screening and 74%
showed DPOAEs indicative of impaired cochlear function.
Hyperacusis and otitis media

J astreboff & Jastreboff (2000) defined hyperacusis as “abnormally strong
reactions occurring within the auditory pathways resulting from exposure to even a
moderate sound level” (p. 156). They defined “phonophobia” as “abnormally strong
reactions of autonomic and limbic systems without abnormally high activation of

auditory system resulting from enhanced connections between the auditory and limbic

system” (p. 156). They noted that individuals with phonophobia have developed fear of
sound as the result of their hyperacusis.

Dix, Hallpike, and Hood (1948) reported that patients with sensorineural hearing
loss who complain of discomfort from loud sounds are diagnosed as having “loudness
recruitment.” Loudness recruitment has been defined as “an abnormally rapid growth of
loudness” (p.219) in individuals with cochlear impairment (Mendel, Danhauer, & Singh,
1999) and is a phenomenon similar to the hypersensitivity to loud sounds seen in
hyperacusis. The commonality between hyperacusis and auditory recruitment is
intolerance of loud sounds.

The phenomenon of hyperacusis has been reported in greater than 95% of the
individuals with WS (Klein et al., 1990; Nigam & Samuel, 1994; Van Borsel et al.,
1997). Klein et a1. investigated the prevalence of hyperacusis and otitis media in
individuals with WS by conducting a survey. They noted that earlier attempts to obtain
audiometric data from individuals with WS had been unsuccessful because of factors
related to age, hyperactivity, and/or developmental age. Thus, they used a survey
approach rather than a complete audiological assessment (i.e., threshold audiogram, high-
level speech discrimination, and acoustic reflex measures).

Participants for the survey were recruited from a Williams Syndrome Association
membership list of four southeastern states. A questionnaire was sent to 100 parents of
individuals with WS. Sixty-five surveys (65%), covering 36 male and 29 female
individuals ages 1 to 28 years, were completed and returned. Children attending a
pediatric, general dentistry clinic served as a normal control group. The control group

included 32 males and 33 females between the ages of 2 to 17 years. According to

parental report, prevalence for hyperacusis was 95% in the individuals with WS and was
12% in the control group. Specific information about offending sounds and the reactions
to these sounds were also reported in this study. Firecracker, power saw, electronic drill,
fire engine siren, motorcycle, loud auto muffler, and blender were each selected by more
than 60% of the parents in this survey. Thunder, the most common write-in answer, was
reported by 19% of parents. Sounds that are not usually associated with threatening
events such as automatic icemaker, television test tone, newspaper crackling, and church
bells were added to the list by some parents. Loud (73%) and sudden (74%) were the
descriptive characteristics of offending sounds most frequently selected by parents.

In the Klein et a1. study, the prevalence of otitis media in the WS population
(61%) was significantly greater than the prevalence in the normal group (30%). The
Spearman rank-order correlation coefficient was used to investigate the relationship
between frequency of otitis media and the overall hyperacusis rating. A significant
relationship could not be established (r = .156, p < .10) in that study. The authors
reported that, among individuals with WS, boys tend to have more episodes of otitis
media than girls, and girls tend to have the placement of tympanostomy tubes slightly
more often.

In the case study presented by Nigam and Samuel (1994), a left middle ear
pathology, left conductive hearing loss and the phenomenon of hyperacusis were reported
in a 21-month-old child. They described the subject’s responses to sounds as a result of
lack of exposure to environmental sounds due to temporary conductive hearing loss
secondary to middle ear pathology. Nigam and Samuel reviewed the previous WS

research, but failed to find support for their lack-of-exposure hypothesis.

Van Borsel et al. (1997) obtained survey data on hyperacusis and otitis media in
individuals with WS. Their questionnaire was similar to the questionnaire used by Klein
et al. (1990). The survey was mailed to all parents of children in the Dutch and the
Flemish WS associations. The number distributed was not reported. Eighty-two usable
questionnaires were returned from the parents. The ages of the individuals with WS
ranged from 1 year 10 months to 45 years 5 months. Only 4 (5%) out of 82 subjects had
“never been frightened or bothered by sounds” (p. 128). The majority of the participants
(83%) reported “oversensitivity” to sounds and the remaining participants (12%) reported
that they had experienced this problem in the past. Parental report showed that
individuals in that 12% had outgrown their fear of sounds at ages ranging from several
months to 22 years. The authors did not differentiate hyperacusis and phonophobia in
their subjects.

Fifty-four percent of the WS subjects in the Van Borsel et al. study noted above
were reported to have had episodes of otitis media, and 76% were reported to show
behavior indicative of attention deficit hyperactivity disorder. Van Borsel et al. reported
that the tendency for boys to have more episodes of otitis media and girls to have more
placements of tympanostomy tubes, reported by Klein et al. (1994), could not be
observed in their study. The Spearman rank-order correlation coefficient was used to
investigate the relation between frequency of otitis media and the overall hyperacusis
rating, and no significant relation could be established (r = -.l285, p = .253).

Auditory verbal strengths
Individuals with WS show a relative strength in verbal short-term memory

(Mervis etal., 2000; wain & Yule, 1991). This ability has been hypothesized to provide

an important foundation for later vocabulary acquisition (Mervis, Robinson, Rowe,
Becerra, & Klein-Tasman, 2003). Even when demonstrating mild-to-moderate mental
retardation, children with WS will frequently score within 1 standard deviation of the
general population on standardized measures of auditory rote recall and working memory
(Mervis et al., 2003).

Neville et a1. (1994) investigated the impact of auditory sensitivity on the
development of individuals with WS using the event-related potential (ERP) technique.
Four children (two males and two females) ages 10 to 14 years and four adults (one male
and three females) served as subjects for their study. One of the adults was tested both as
a child at the age of 14 and as an adult at the age of 18. They also recruited normal
control children and adults. Approximately half of the control subjects were male. The
paradigm of Auditory Recovery Cycle was designed to study the early stage of auditory
sensory processing and the neural basis for the hypersensitivity to sounds that individuals
with WS showed. One thousand and 1,500 Hz tonal stimuli were presented through
earphones. Ninety percent of the stimuli were 1,500 Hz tones, and the others were 1,000
Hz tones. The subjects were asked to respond the target tones (1,000 Hz) by pressing a
button. The second part of the research was to investigate the early and late neural
systems that may be important to auditory language processing in individuals with WS
and also to compare the organization of neural systems important to reading in those who
learned to read earlier versus later. In separate conditions, subjects listened to or read
sentences and then judged whether the sentences made sense. Sample sentences provided

by authors included, “After the snow they clapped their hands” and “I don’t go to school

on Saturday or floor” (p. 71). ERP measures were recorded during both the tone and the
sentence tasks.

The results showed that tone-elicited ERPs from the individuals with WS showed
a normal morphology; however, they were considerably less refractory than tone—elicited
ERPs of the normal controls. That is, a short interstimulus interval reduced the amplitude
of response in the normal controls but not in the individuals with WS. During the
sentence task, the ERPs elicited with visually presented words were the same for the
control subjects and the individuals with WS. However, the morphology of ERPs elicited
during listening tasks in individuals with WS were described as highly abnormal and
characterized by a greater positive/enhanced response to related lexical items. The pattern
of results in this study suggested that the organization and operation of cognitive systems
could be influenced by alterations in early sensory processing. Neville et a1. concluded
that the ERP evidence of hypersensitivity in the auditory systems of individuals with WS
may provide important clues to the processes underlying the precocious nature of
language skill development in these individuals. They also noted that the ERP data
provide insight into differences in auditory and visual processing by individuals with WS.
Audiological evaluation of individuals with cognitive impairment

Individuals with WS and individuals with Down syndrome (DS) demonstrate an
equivalent cognitive impairment (Bellugi, Wang, & Jemigan, 1994) and a high
prevalence of otitis media (Balkany, Downs, & Jafek, & Krajicek, 1979; Klein et al.,
1990; Van Bosel et al., 1997). Research in developing hearing assessment strategies for
use with individuals with WS has not yet been initiated. As was discussed earlier,

researchers have reported difficulties in conducting audiological assessment in

10

individuals with WS (Klein, 1994). Therefore, data concerning individuals with D8 will
be used as a foundation for determining procedures to be used with individuals with WS.

Kile (1996) provides a summary of the types of modifications that can be made to
standard assessment procedures so that the procedures are appropriate given the
behavioral characteristics of children with DS (e. g., social responsiveness, tendency to
produce echolalic imitations). He reported that children with DS usually show compliant,
interactive behavior during audiologic assessment, and that a wise use of social and
tactile interaction and reinforcement often keeps them focused and increases time
available to obtain reliable results. Children with DS tend to make more echolalic
imitations than do normally developing children (Rondal, Lambert, & Sohier, 1981);
therefore, Kile suggested that teaching children with DS to mimic auditory stimuli can
increase consistency of response when conventional behavioral testing procedures are not
successful. Kile also reported success using this modification in a l2-year-old child with
DS who was seen in his clinic. This child could not be conditioned to do play audiometry
and did not show consistent responses in VRA; however, he responded to pure tones by
saying “Beep Beep.” Kile noted that pure-tone threshold measures were obtained using
this modification.

Kile conducted the ear canal volume measures for 10 children with DS and 10
children with normal development, and reported that children with DS showed a smaller
ear canal volume than normally developing children. He recommended that the
establishment of the ear canal volume measures of children with DS can be helpful when
comparing pre- and post-tympanometry tube placement measurements. In order to

investigate the prevalence of otitis media in children with DS, Kile evaluated 47 children

11

(mean age = 3.6 years) with DS in his clinic. He reported that 74% of the children with
DS in his project demonstrated abnormal tympanograms that were consistent with the
presence of otitis media, and that 58% of them had this condition bilaterally.

Kile also suggested that otoacoustic emission (OAE) measures may be useful in
assessing cochlear function in children with DS. However, OAEs can only provide
accurate information when individuals do not have middle ear disease. Kile
recommended that, due to the high incidence of middle ear disease and the risk of hearing
impairment in children with DS, early identification of hearing loss in children with DS is
critical and audiologic assessment should be performed every four to six months once the
hearing loss has been diagnosed.

Dille (2003) summarized strategies for effective testing, as well as common
findings, for individuals with DS across the lifespan. Her report was based on a review of
previous research concerning hearing assessments of individuals with DS. Dille reported
that behavioral testing procedures such as VRA are successful when the appropriate
developmental criterion is used. She noted that VRA procedures provide reliable
audiometric information when children with DS have obtained a developmental age of 10
to 12 months, due to delayed sound localization skills in children with DS (Greenburg,
Wilson, Moore, & Thompson, 1978). Dille reported “pure-tone testing to be reliable for
children with DS only after 8 years of age, whereas objective procedures are more
reliable for the younger p0pulation” (p. 204).

Dille recommended the use of objective techniques (e.g., ABR, DPOAE) to

diagnose hearing loss in adults and children with DS, and she also noted that even when

12

individuals with DS have normal tympanometry and audiometry, their DPOAE measures
demonstrated lower amplitude than normal age-peers.

Keiser, Montague, Wold, Maune and Pattison (1981) collected complete sets of
audiometric information, including air- and bone-conduction thresholds, tympanometry
and acoustic reflexes from 51 adults with DS (aged 15.1 to 51.6 years). They obtained
pure—tone thresholds using standard pure-tone audiometry (hand-raising response) or
conditioned play audiometry from 46 of the 51 participants. They used 15 dB HL as the
criterion for identifying hearing loss, and found that 75% of the participants exhibited
hearing loss in at least one ear. This study showed a sloping sensorineural hearing loss
above 4,000 Hz, which is indicative of early presbycusis, and this configuration became
significant by adolescence and progressedthroughout their lifespans. They also reported
that tympanograms from 39 % of the tested ears suggested abnormal middle ear function.
Their study also indicated that reliable thresholds could be obtained using conventional
pure-tone audiometry both for older children (15 years old and older) and for adults with
DS.

Review of the available literature showed that procedures for the assessment
hearing loss in individuals with DS have been well established. Because characteristic
similarities between WS and DS have been reported in the literature (Bellugi et al., 1994;
Balkany et al., 1979; Klein et al., 1990; Van Bosel et al., 1997), hearing assessments for
individuals with DS may be modified for use with individuals with WS. Modified
behavioral assessments described by Kile ( 1996) and Dille (2003) provide important
information on how to approach behavioral assessment of individuals with WS based on

the characteristics of individuals with DS. Once children with WS have developed the

13

skill of sound localization, VRA can be introduced to estimate behavioral thresholds.
Modified VRA using earphones can be introduced to obtain behavioral thresholds in
young children who are not able to do conditioned play audiometry. Conditioned play
audiometry can be used to obtain thresholds in children by age 8 years who are able to
demonstrate reliable responses to pure-tone stimuli. For adults, conditioned play
audiometry and conventional pure-tone audiometry with verbal or hand-raising response
can be used for hearing assessment.
Summay

In summary, previous research reports from independent labs have indicated a
prevalence of sensorineural hearing loss in individuals with WS ranging from 33%
(Ruangdaraganon et al., 1999; Johnson et al., 2001) to 74% (Marler et al., 2004). These
studies have included small numbers of participants, provided incomplete data about test
protocols, failed to define the degree of hearing loss, or have reported auditory
information gathered in acoustically uncontrolled environments. As a result,
interpretation of these data is confounded and application of the data to a clinical setting
is limited.
Rationale for the current study

The hearing acuity of individuals with WS has not yet been well documented. It is
necessary to establish audiometric performance in individuals with WS before the
strengths or weaknesses of auditory processing and language abilities in WS can be
accurately evaluated. The purpose of this research project was to test objectively whether
individuals with WS are more sensitive to auditory stimulation (i.e., have better-than-

normal thresholds) than their normally developing age-peers.

14

l)

2)

3)

The goal of this project was to answer the following questions:

Do individuals with WS have normal hearing?

Although the data available regarding prevalence of hearing loss in individuals
with WS are incomplete, there is growing evidence that a significant portion of
this population demonstrates hearing loss. Therefore, it was hypothesized that the
prevalence of hearing loss is greater in individuals with WS than in normally
hearing age peers.

Is there normal outer hair cell function in the individuals with WS?

Although hyperacusis has been seen as a phenomenon similar to loudness
recruitment, few studies have used OAE data to investigate the outer cell function
of individuals with WS who demonstrated hyperacusis. Johnson et al. (2001) had
subjects with normal hearing and absent OAEs; Marler et al. (2004) did not.
Neither set of authors presented hyperacusis data for their subjects. It was
hypothesized that the outer hair cell function measured by DPOAE in the current
study would be consistent with audiometric data.

Do individuals with WS report discomfort from sound levels that are below the
loudness discomfort level typically reported by individuals with loudness
recruitment associated with sensorineural hearing loss?

Although hypersensitivity to sounds has been reported in previous studies,
information on loudness discomfort levels in individuals with WS is not available.
It was hypothesized that individuals with WS will demonstrate lower loudness

discomfort levels than individuals with sensorineural hearing loss.

15

CHAPTER 2
Method
Participants

Seven individuals with WS, between the ages of 7 to 43 years, were recruited
through contacts with the Great Lakes Region branch of the National Williams Syndrome
Association, special-needs educators, geneticists, and private physicians, and through
advertisements placed in local and regional association newsletters. All subjects
participated in a broad study of communication skills conducted under the direction of
thesis co-advisor Jeffrey Marler. Only the audiological data gathered are reported here.

FISH was previously completed on all the participants in the current study. The
results were either reviewed by Michael Netzloff, M.D., Director of Clinical Genetics at
Michigan State University (MSU) for confirmation of the diagnosis of WS, or were
confirmed by previous participation in the longitudinal projects of Carolyn B. Mervis,
Ph.D., Director of the Cognition and Language Laboratory at the University of
Louisville. In all cases, FISH revealed the absence of one copy of the elastin gene on
chromosome 7 and all had clinical phenotype characteristics of WS.

Following explanation of the study, a parent or a legal guardian of each
participant was asked to read and sign an informed consent form. In addition, all
participants were asked to sign an assent form. Consent procedures were approved by the
MSU University Committee on Research Involving Human Subjects (UCRIHS IRB #02-
534). Each participant was paid $15 for participating in this study.

Due to the low incidence of WS, participants were recruited from a wide

geographic area; some of the participants had to travel hundreds of miles and stayed in a

16

hotel the night before attending this study. Thus, it was not possible to recruit each
participant for a second visit to assess test-retest variability in performance. Table 1
provides gender and age data for the seven participants in this project.

Table 1. Gender antljge data for each participant (M: Male; F: Female).
Chronological Age

 

Part1c1pant # Gender (years; months)
ws001 M 43;1
ws002 F 392
WSOO3 M 175
WSOO4 M 26:2
wsom M 7:1
WSOl8 F 7:8
wsozs F 1 “8
13mm

Table 2 provides a summary of the test battery administrated to each participant.
The test battery was modified to meet the individual needs of the participants (i.e., short
attention span, difficulties in understanding the task, fatigue, fear of the probes placed in
their ears). All the audiometric data were collected by the author under the supervision of
an ASHA certified speech-language pathologist and/or an ASHA certified audiologist.

Table 2. Summary of quantitative measures administrated to participants in the current
study.

 

Measures Independent Variable Dependent Variable
Air-conduction thresholds dB HL (.5 to 8 kHz) Auditory sensitivity
Bone-conduction thresholds dB HL (.5 to 4 kHz) Auditory sensitivity
Tympanometry daPa at tympanic peak Middle ear status
Speech recognition threshold (SRT) dB HL Speech perception ability
Word recognition score (WRS & % Correct Speech perception ability
NU-6 list)

DPOAE dB SPL Outer hair cell function
(Cochlea integrity)

 

Pure-tone thresholds
The goal was to obtain air-conduction thresholds for the frequency range of 500

to 8,000 Hz, and bone—conduction thresholds for the frequency range of 500 to 4,000 Hz

17

at octave intervals. For the first four participants, these measures were made after the
language measures that were part of the broader study. After that portion of data
collection was completed, it became clear that to reduce the impact of factors such as
fatigue and short attention span on the participants’ responses, the audiometric data
needed to be collected at the beginning of each participant’s session before the language
measures were administered. For this reason, the audiometric data were gathered first for
the last three participants.

The signals for the standard pure-tone audiometry were pulsed tones generated by
a GSI- 16 audiometer and delivered by TDH-49 earphones or mastoid placement of a
bone conduction vibrator. Participants were seated in an Industrial Acoustics Corporation
test booth during this portion of the study. Adult participants were asked to respond to
stimuli by raising a hand, and children performed a play audiometry task in which they
put a block in a puzzle board. Thresholds 2 20 dB HL at any frequency in adults and 15
dB HL at any frequency in children were considered to indicate hearing loss. The degrees
of hearing impairment were defined using the categories recommended by Jerger and
Jerger (1980) for adult participants and by Northern and Downs (2002) for child
participants. The criterion for identifying hearing loss as sensorineural was that there be
no more than a single air-bone gap greater than 10 dB HL in the pure-tone thresholds. For
the individuals for whom the masked bone-conduction thresholds could not be obtained.
the results of tympanometry were used to rule out middle ear pathology.

One individual in the current study was able to participate in extended high-
frequency air-conduction audiometry in addition to the basic audiometric test battery.

Extended high-frequency air-conduction audiometry, gathered for 10,000, 12,500, and

18

16,000 Hz stimuli, was conducted using a Madsen Orbiter 922 Version 2 audiometer and
Sennheiser HDA200 earphones. Both GSI- 16 and Orbiter 922 Version 2 systems were
calibrated to the ANSI-1989 audiometric standard (ANSI, 1989).

Otoscopy and tympanometry .

Otoscopy was performed to evaluate the status of the participants’ external ear
canals and tympanic membranes. Middle ear function in six of seven participants was
evaluated using a GSI-33 middle ear analyzer using a 226 Hz probe tone and a pump
speed of -200 daPa/s. Data for the seventh participant (WS018) were obtained using a
GSI 28 handheld tympanometer due to technical problems with the GSI-33 at the time of
data collection. To avoid the possibility that participants’ concerns about this procedure
would interfere with other aspects of data collection, these data were collected at the end
of the assessment session.

The “pass” for tympanometry for adults was a static admittance (Peak Y)
occurring between +100 and -150 daPa and peak compliance 2 0.3 mmho, an equivalent
ear-canal volume (Vec) between 0.6 and 1.5 ml (ASHA, 1990), and a gradient > 0.2
(Gelfand, 2001). The “pass” criteria for children was a static admittance occurring
between +100 and -150 daPa and peak compliance 2 0.2 mmho, an equivalent volume
(Vec) between 0.4 and 1.0 ml (ASHA, 1990), and a gradient > 0.2 (Nozza, Bluestone,
Kardatzke, & Bachman, 1992).

fieech audiometry

The goal was to measure speech threshold and understanding of speech at
suprathreshold levels in individuals with WS. Speech audiometry was performed with a

GSI-16 audiometer using CD recordings prepared by Auditech of St. Louis. Standard

19

spondee lists were used to obtain speech recognition thresholds (SRT) for each ear, and
the Northwestern University Auditory Test Number 6 (NU-6; Tillman & Carhart, 1966)
lists were used to obtain word recognition scores for each ear. Stimuli for the word
recognition tests were presented at 30 dB SL re: SRT for participant WS001; however,
after the discovery of high frequency hearing loss in participant WSOOl, the presentation
level was changed to 40 dB SL re: SRT, which is more efficient for both individuals with
normal hearing and with hearing impairment (Gelfand, 2001).

Both NU-6 and the Phonetically Balanced Kindergarten word lists (PBK-50;
Haskins, 1949) were used to obtain word recognition scores for WS001. However, after
working with children with WS at the national conference, it was hypothesized that given
the verbal memory and language skill strengths of individuals with WS, even the children
would be able to respond to the N U-6 list. The intent was to begin with an NU-6 list and
shift to a PBK—50 list if necessary. As will be noted later, problems with factors such as
fatigue precluded assessment of word recognition in the children who participated in the
study.

Otoacoustic emissions data

The goal of this task was to investigate outer hair cell function in individuals with
WS. Distortion product otoacoustic emissions (DPOAEs) were obtained using an
Intelligent Hearing System (IHS) SmartOAE instrument. Data were collected for each ear
in response to primary tones (labeled f1 and f2), with the ratio of these frequencies (f2/f 1)
equal to 1.22. The frequency of f2 varied from 1,000 to 8,000 Hz in 1/8-octave steps.
Twenty-five pairs of frequencies were presented and data from 16 sweeps were recorded

and averaged for the response to each pair. Primary levels were set to f1 = 65 dB SPL and

20

f2 = 55 dB SPL. The criterion for an emission consistent with hearing loss was that it be
below the 5‘h percentile for ears with normal hearing as reported by Gorga et al. (1997).

Loudness discomfort level (LDL) rating

The goal of this condition was to measure the loudness discomfort levels (LDLs)
in individuals with WS and determine whether individuals with WS demonstrate lower
LDLs for multi-talker babble and/or speech noise than would be expected in the general
population. Speech noise generated by a GSI-16 audiometer was used for these
measurements because for normally hearing individuals, speech-like signals yield lower
thresholds of discomfort than do pure-tone signals (Dirks & Kamm, 1976). Thus, the
impact of hyperacusis might be more readily observed with speech noise than with tones.
In addition, the l2-talker multi-talker babble from the Revised Speech Perception in
Noise Test (R-SPIN; Bilger, Nuetzel, & Rabinowitz, 1984) was used in this task to obtain
the data to reflect real-world noisy communication situations.

In order to investigate a broad range of tolerance levels, the softest stimulus was
presented at 5 dB HL, and the loudest stimulus was presented at 65 dB HL. Due to the
concern that individuals with WS would not be able to tolerate loud stimuli, an upper
level of 65 dB HL (approximately 85 dB SPL) was selected, lower than the loudness
discomfort level for speech stimuli (100 dB SPL) obtained from a normal—hearing
population reported by Dirks & Kamm (1976). Stimuli were presented binaurally at
ascending levels of 5 to 65 dB HL in 10-dB steps, using TDH-49 earphones. Participants
were asked to rate the signals on a five-point scale. Due to WS subjects’ remarkable
ability to process affect (Bellugi et al., 2000), and to recognize, discriminate, and

remember unfamiliar and familiar faces (Rossen, Jones, Wang, & Klima, 1995), a picture .

21

with five iconic faces was provided for this task (Figure 1). This picture was revised from
Kawell, Kopun, and Stelmachowicz ( 1988) by changing the facial expressions and the
wording of the rating scale. The surprised face with the word “hurts” used by Kawell et
al. (1988) was removed to prevent upsetting individuals with WS who report
oversensitivity to loud sounds. The facial expression “just right” in Kawell et al. (1998)
was moved from the second lowest level to a neutral place (Number 3) in the current
study and the wording was changed to “OK.” The instructions for this task were

Figure 1. Picture provided for LDL rating measure.

“mm/om

\/\/\\ <;:/\:/

CAN‘T T00 T00
SOFT 0. K. LOUD LOUD

“You will hear different sounds. Point to the faces on this paper to show me how you
feel. If you cannot hear it, just wait. If it is soft, point to this one (Number 2). If you feel
comfortable, just like listening to music, point to this one (Number 3). If it is a little loud,
but does not bother you, point to this one (Number 4). If it is too loud and you want me to
turn it off, point to the last one (Number 5).” Signals were presented binaurally in a
random order. Each signal level was presented twice. If the participant’s response on the
second trial was not consistent with the first, then the level was presented a third time.
The responses rated “5 (Too Loud)” were recorded as the individuals’ LDL to the

stimulus. Participants’ responses to both speech noise and multi-talker babble were

22

obtained using this task. The data for the speech noise were collected first, and then the
multi-talker babble data were collected.

Hyperacusis questionnaire

A hyperacusis questionnaire that was an expansion of the form used by Klein et
al. (1994) was provided to the parents of each participant. This questionnaire was .
constructed to obtain data on the prevalence of hyperacusis and otitis media, and was
modified from Klein et al. by adding questions about the participant’s past and present
responses to sounds in order to investigate the relation between age and hyperacusis. A
copy of the form is available in Appendix A. This questionnaire was either completed
during the data-collection session or mailed back afterward. In order to be able to
compare the results with the Klein et al. data, questions regarding the participant’s
behaviors covered hyperacusis and phonophobia together rather than as different

responses to sounds.

23

CHAPTER 3
Results

Audiological assessment

Otoscopy

For participants W800], WSOO2, W8003, WSOO4, WSOl8, and WS028, otoscopy
revealed external canals within normal limits, no excessive cerumen and intact tympanic
membranes. Otoscopy could not be performed on WSOl6 due to his unwillingness to
allow the otoscope to be placed in his ears.

Immitance

Tympanograms were obtained for both ears in five of the seven participants, and
the results from four of five showed normal static admittance, equivalent volume,
gradient and compliance. Participant WSOOl ’3 had ear canal volumes greater than 90% of
the ASHA (ASHA, 1990) data; however, his tympanograms suggested normal middle ear
function. Tympanometry was accomplished only for the left ear in child participant
WSOl6 and showed middle ear stiffness (flat tympanogram with ear canal volume 0.4
ml). Tympanometry for the right ear in W8016 could not be conducted due to the lack of
a good seal and his unwillingness to continue this task. Tympanometry was attempted
with child participant W8028, but could not be conducted because of her unwillingness to
allow the probe to be placed in her ears. The individual data of Immitance measures are
listed in the Appendix B.

Pure-tone audiometry

Air-conduction and bone-conduction thresholds for stimuli from 500 to 8,000 Hz

for each participant are shown in Figure 2. Standard pure-tone thresholds were obtained

24

from all the participants, and extended high-frequency pure-tone thresholds were
obtained from adult participant WSOO4. Thresholds Z 20 dB HL at any frequency in
adults and 15 dB HL at any frequency in children were considered to indicate hearing
loss. The criterion for identifying hearing loss as sensorineural was that there be no more
than a single air-bone-gap Z 10 dB HL in the pure-tone thresholds. The degrees of
hearing impairment were defined using the categories recommended by Jerger and Jerger
(1980) for adult participants and by Northern and Downs (2002) for child participants.
Five of the seven participants (WSOOI, WSOOZ, WSOO4, WSOl 8, and WSO28) in the
study demonstrated bilateral sensorineural hearing loss and three of those five
participants (WSOOI , WSOO2, and WSOlS) showed a pattern of high frequency hearing

loss.

Figure 2. Hearing thresholds for each participant (0: Right ear air-conduction thresholds;
X: Left ear air-conduction thresholds; <: Unmasked right ear bone-conduction thresholds;
>: Unmasked left bone-conduction thresholds; [: Masked right ear bone-conduction
thresholds; ]: Masked left ear bone-conduction thresholds).

Frequency in Hz
250 500 1000 2000 4000 8000

 

-1D

10 4%\;\ k

‘r

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Hearing thresholds in dB HL (ANSI 1989)

 

 

 

 

 

 

 

 

100 %
11o ‘ i ‘ ‘

 

WS001

25

Figure 2 (continued). Hearing thresholds for each participant (0: Right ear air-conduction
thresholds; X: Left ear air-conduction thresholds; <: Unmasked right ear bone-conduction
thresholds; >: Unmasked left bone-conduction thresholds; [: Masked right ear bone-
conduction thresholds; ]: Masked left ear bone-conduction thresholds).

Frequency in Hz
250 500 1000 2000 4000 8000

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

'10 . E 3 z
s 0 f: ,? L
a) ‘ = i 5
r: 10 {pm RX? 13
(3 20 5 = Q>)<‘X\
5" 5\o
"I" 30 : 33k
% 4° * 2\
c
é 5° ‘ x
25 60 - ‘
.5
g 70
5
o, 80
.s
a 90
03
I100 - e -

110

WS002
Frequency in Hz
10 250 500 1000 2000 4000 8000

 

 

° 37%m\<>7&_

/ .
10 <ߤ VI -\X/g

 

 

 

 

 

 

 

 

 

 

Hearing thresholds in dB HL (ANSl 1989)

 

 

 

 

 

 

 

 

 

110

 

WSOO3

26

Figure 2 (continued). Hearing thresholds for each participant (0: Right ear air-conduction
thresholds; X: Left ear air-conduction thresholds; <: Unmasked right ear bone-conduction
thresholds; >: Unmasked left bone-conduction thresholds; [: Masked right ear bone-
conduction thresholds; ]: Masked left ear bone-conduction thresholds).

Frequency in Hz
250 500 1000 2000 4000 8000

-10
0
10
20

Hearing thresholds in dB HL (ANSI 1989)
5‘ 8 8 s

8888

 

1
WSOO4

Frequency in Hz
250 500 1000 2000 4000 8000

Hearing thresholds in dB HL (ANSI 1989)

 

WS016

27

Figure 2 (continued). Hearing thresholds for each participant (0: Right ear air-conduction
thresholds; X: Left ear air-conduction thresholds; <: Unmasked right ear bone-conduction
thresholds; >: Unmasked left bone-conduction thresholds; [: Masked right ear bone-
conduction thresholds; ]: Masked left ear bone-conduction thresholds).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Frequency inHz
10 250 500 1000 2000 4000 8000
a o :< =
:10 i< IL,“
g 20 g/n . X\\;< ,0
3 s : *\ a
“8 4° X
r: 5 i 5 i
3”; 5° ’ ' i
'5 60
-=
:6 70 :
5
or 80 T
.E '
g 90
I100
110 ,
VVS018
Frequency inHz
10 250 500 1000 2000 4000 8000
a? ‘ 5 5
co 0 e I ‘
a) a
g 10 > 1 :/)u
3.; 20 <>\ ,,a;x—
\ s
33‘ Xfix:
98 4° :
C'. :
E: 5"
'5 60 f
4: s
3 70 ;
5
on 80 l
.E
a 90
0
I100
110

WS028

28

Participant WS001 demonstrated hearing within normal limits through 2,000 Hz
in both ears. Thresholds above that point were indicative of a mild, sloping sensorineural
hearing loss in the right ear and a mild-to-moderate, sloping, sensorineural hearing loss in
the left ear. False-positive responses were only observed when high-frequency stimuli
were presented and re-instruction was provided when they occurred. Participant WSOOl
was one of the two individuals in the current study who reported presence of tinnitus
during the test. It is possible that participant W800] had difficulty discriminating
between the pure-tone stimuli and his tinnitus. The reliability of his pure-tone data was
judged to be good.

Pure-tone thresholds for participant WS002’s right ear were within normal limits
through 4,000 Hz, and then indicated mild sensorineural hearing loss at 8,000 Hz. Left
ear pure-tone thresholds were within normal limits through 2,000 Hz, and were indicative
of mild-to-moderate, sloping, sensorineural hearing loss. The reliability of her pure-tone
data was judged to be good. Participant W8002 showed a bone-conduction threshold
poorer than air-conduction thresholds (i.e., a reverse air-bone-gap) at 4,000 Hz in both
ears. The air-conduction and bone-conduction thresholds are within ilO dB of each
other; therefore, “it is possible and perfectly acceptable for a bone-conduction threshold
to be a bit poorer than air-conduction thresholds at the same frequency, even if
everything is done correctly” (Gelfand, 2001, p. 155-156). However, the 20 dB reverse
air-bone-gap at 4,000 Hz in her right ear was not typical. The placement of the bone
oscillator was checked and the thresholds at 4,000 Hz were re-tested during the data
collection in order to rule out technical errors. It is important to note that participant

W8002 also reported the presence of ringing in her ears during the test. It is possible that

29

participant WS002 had difficulty discriminating between the pure—tone stimuli and her
tinnitus.

Participant WSOO3 was the only participant in the current study who showed
normal pure-tone thresholds across the entire test frequency range in both ears. The
reliability of his pure-tone data was judged to be good. Although the audiogram of
WSOO3 showed a 15 dB air-bone gap at 4,000 Hz in the left ear, tympanograms for both
of W8003’s ears revealed normal middle ear function. Therefore, the air-bone-gap at
4,000 Hz in the left ear was not considered to indicate the presence of a conductive
component to the hearing loss.

Participant WSOO4 demonstrated a bilateral mild (500 to 2,000 Hz) to moderate
(above 2,000 Hz) sensorineural hearing loss. He showed some inconsistent responses to
the stimuli during this task and re-instruction was provided when false—positive responses
occurred. The reliability of his pure-tone data was judged to be only fair due to his
inconsistent responses.

One child (WS016) showed a left unilateral hearing loss of an unidentified type.
Tympanometric data for that ear were indicative of middle ear pathology, and mixed
hearing loss could not be ruled out without bone-conduction data. Bone-conduction data
were not collected because the child lost interest in the task and could not be coaxed to
continue. The reliability of his pure-tone data was judged to be fair.

Pure-tone thresholds for participant WS018’s left ear showed mild, rising,
sensorineural hearing loss at 500 to 2,000 Hz, and then indicated mild-to-moderate,
sloping, sensorineural hearing loss range in the high frequencies. Air-conduction

thresholds for the right ear were obtained only from 1,000 to 8,000 Hz due to the

30

participant’s loss of interest in the task. Right ear pure-tone thresholds showed a mild
sensorineural hearing loss at 1,000 Hz, then a rise to the normal hearing range at 2,000
Hz, and finally a slope to mild hearing loss range at 4,000 to 8,000 Hz. The reliability of
his pure-tone responses was judged to be good. No bone-conduction threshold was
obtained at 500 Hz due to participant WSOl8’s loss of interest in the task. Sensorineural
hearing loss at 500 Hz in the left ear was confirmed by the normal immitance results for
WSOl8.

Pure-tone thresholds for participant WS028’s right ear showed mild-to-moderate,
sloping, sensorineural hearing loss from 500 to 1,000 Hz, then a rise to mild, essentially
flat, sensorineural hearing loss at 2,000 to 6,000 Hz, and finally a rise to normal—hearing
range at 8,000 Hz. Left ear pure-tone thresholds showed mild to moderate, essentially
flat, sensorineural hearing loss at 500 to 1,000 Hz, then a rise to mild, essentially flat,
sensorineural hearing loss at 2,000 to 8,000 Hz. Due to WSO28’s fear of earphone
placement and refusal to stay in the testing booth at the beginning of the audiological
evaluation, the procedure was modified to help participant WSO28 gradually overcome
her fear. Play audiometry, using a Beltone 120 portable audiometer, was performed
during the language evaluation session to help the participant get used to the earphone
placement. WS028 was conditioned to put a block in a puzzle board when she heard
pulsed tones through the earphones. VRA using FM signal (warble tones) was introduced
after play audiometry to help her become comfortable with the testing booth. After this,
participant WS028 was able to do play audiometry (using pulsed tones) in the testing
booth, and her pure-tone data were collected using the G51 61 audiometer. The reliability

of her pure-tone data was judged to be good.

31

Extended high-frequency (EHF) data were obtained only for WSOO4, and they
were converted to dB SPL by adding the reference equivalent threshold sound pressure
levels (RETSPLs) recommended by Frank (2001). The test reliability was judged to be
fair due to his false positive responses to stimuli. Table 3 shows the data comparison of
EHF air-conduction thresholds of WSOO4 and the mean data of 32 individuals (16 male
and 16 female) aged 20 to 30 years reported by Stelmachowicz, Beauchaine, Kalberer
and Jesteadt (1989). These data were used for comparison because they were obtained
from a population that included the age range of the adult participants in the current study
(i.e., 240 individuals in the range of 10 to 60 years), the subgroups of each age range
contained equal numbers of male and female individuals, and all of the individuals were
reported to have normal middle ear function and a negative history of excessive noise
exposure or ototoxic drug use. The data comparison shows that W8004’s EHF thresholds
were 56.6 dB or greater than the mean data for individuals aged 20 to 30 years reported

by Stelmachowicz et al. (1989).

Table 3. Data comparison of extended high-frequency air-conduction thresholds obtained
from WSOO4 and mean thresholds for 32 individuals age 20 to 30 years reported by
Stelmachowicz et a1. (1989).

 

 

Right Ear (dB SPL) Left ear (dB SPL)
Frequency (kHz) 10 12.5 16 10 12.5 16
WSOO4 87.6 NR NR 112.6 NR NR
Stelmachowicz et al., 1989 31 38 72 31 38 72

 

NR: No response when stimuli reached the maximum audiometer output.

Speech audiometg

Speech recognition thresholds (SRT) and word recognition scores (WRS) were
obtained from the four adult participants, ages 17 to 43 years. Pure-tone averages were

calculated using the thresholds for 500, 1,000, and 2,000 Hz, the SRT data, and the WRS

32

data are shown in Table 4. Each of the adult participants demonstrated excellent word
recognition as indicated by scores 2 92%. Speech audiometry could not be conducted
with three child participants due to their loss of attention to the task.

Table 4. Speech audiometry and pure-tone-average data for the four adults who completed
the speech audiometry tasks.

 

Right Ear Left Ear
PTA SRT WRS PTA SRT WRS
Presentation % Presentation %
level (dB HL) Correct level (dB HL) Correct
WSA001 12 dB 15 dB 45 dB 98 12 dB 15 dB 45 dB 98
WSA002 8 dB 5 dB 45 dB 100 7 dB 0 dB . 40 dB 100
WSA003 5 dB 10 dB 50 dB 96 3 dB 5 dB 45 dB 96
WSA004 38 dB 25 dB 65 dB 100 33 dB 25 dB 65 dB 92

 

Data for three of the four participants indicate consistency between pure-tone
averages (PTA) and SRTs (i.e., a difference that is S 6-12 dB; Brandy, 2002). The fourth
participant’s data were consistent for the left ear but differed by 13 dB in the right ear.
Participant WSOO4 demonstrated some inconsistent responses to pure-tone stimuli and
needed more re-instructions than the other participants during the pure-tone audiometric
measurement. It is possible that this contributed to a slightly elevated pure-tone average.
Any inconsistent responses (differing by more than 5 dB) can lead to a different result in
terms of the consistency between PTA and SRT. This individual also had difficulty
convincing his family members that he has hearing loss. Therefore, it is possible that
WSOO4 exaggerated the severity of hearing loss in order to convince his family that he is

hearing impaired.

33

Otoacoustic emissions data

DPOAE data were obtained from five of the seven individuals (WS001, WSOOZ,
WSOO3, WS004, and W8018). DPOAE measures were attempted with the two remaining
child participants (WSOl6 and WS028), but they could not be conducted because of the
children’s unwillingness to allow the probe to be placed in their ears. DPOAE data for the
participants in this study are shown in Figure 3.

The 95'h percentile data for DPOAE amplitude for hearing-impaired ears and the
5‘h percentile data for DPOAE amplitude for normally hearing ears, as reported by Gorga
et al. (1997) are plotted in Figure 3 for comparison. All points below the Gorga et al. data
(i.e., at a lower dB SPL) have a significant probability of coming from cars with hearing
loss. Data above the 95th percentile for hearing-impaired ears are considered indicative of
hearing within normal limits. Data between the 5‘h percentile for normally hearing ears
and the 95lh percentile for hearing-impaired ears are considered difficult to interpret, and
therefore ambiguous.

Of the five data sets shown in Figure 3, one was from an individual who had
hearing within normal limits (WSOO3) and four were from individuals who demonstrated
bilateral sensorineural hearing loss. The DPOAE data support the audiological finding of
hearing loss in three (WSOOl, WSOO2, WSOl8.) of the four participants who showed
bilateral hearing loss.

Participant WSOOl demonstrated pure-tone thresholds that sloped from within
normal limits to the mild (right) or moderate (left) hearing loss range from 4,000 to 8,000
Hz. His DPOAE amplitudes in the frequency range of 1,500 to 3,000 Hz were indicative

of normal hearing. DPOAE amplitudes fell below the 5‘h percentile of the Gorga et al.

34

data in the frequency range of 4,000 to 6,000 Hz, and thus were consistent with hearing-
impaired ears. Thirty-eight percent of the DPOAE responses from the right ear and 33%
of the responses from the left ear fell within the ambiguous range.

Participant WS002 also demonstrated thresholds that sloped from within normal
limits to the mild (right) or moderate (left) hearing loss range at 8,000 and/or 4,000 to
6,000 Hz. Most of the DPOAE amplitudes above 2,000 Hz in her right car were
indicative of normal hearing. Her DPOAE amplitudes fell below the 5‘h percentile of
Gorga et al. data in the frequency range of 6,000 to 7,000 Hz in the left ear, and thus were
consistent with hearing—impaired ears. Thirty-three percent of the DPOAE responses
from the right ear and 42% of the responses from the left ear fell within the ambiguous
range.

Figure 3. Individual DPOAES for participants WS001, W5002, WSOO3, WS004, and WS018.

 

Mean DPOAE Noise

—xi WSO1 LE

—0— W801 RE

—I— Gorga et al 5th Percentile
-v— Gorga et al 95th Percentile

 

20—

 

 

 

DPOAE Amplitude (dB SPL)

 

 

 

l I l l T l l
1000 2000 3000 4000 5000 6000 70008000
Frequency (Hz)

35

Figure 3 (continued). Individual DPOAES for participants WS001, W8002, WSOO3, WS004,
and WS018.

 

 

Mean DPOAE Noise

—><— W803 LE

—0 — W803 RE

—I— Gorga et at 5th Percentile
—v— Gorga et at 95th Percentile

20-

 

 

 

DPOAE Amplitude (dB SPL)

 

 

 

 

' r l " ' l l 9 l l l l
1000 2000 3000 4000 5000 6000 70008000
Frequency (Hz)

 

 

Mean DPOAE Noise

. —x— W802 LE

—0— W802 RE

—-— Gorga et al 5th Percentile
—v— Gorga et al 95th Percentile

 

 

 

DPOAE Amplitude (dB SPL)

 

 

 

 

A l l I I l I l
1000 2000 3000 4000 5000 6000 70005000
Frequency (Hz)

36

Figure 3 (continued). Individual DPOAES for participants WS001, WS002, WS003, WS004,
and WS018.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

— Mean DPOAE Noise
—x— W804 LE
20 l —0— W804 RE
‘1 —I— Gorga et at 5th Percentile
A —v~ Gorga et al 95th Percentile
..l
n. _
w 10
in
E
8 o -
.3
'a
E
< -10 _
u
<
O
a
D -20 -
-30 ..
' I l i l l l l l
1000 2000 3000 4000 5000 6000 70008000
Frequency (Hz)
—* Mean DPOAE Noise
—x— W818 LE
20 —0— W818 RE
q ——I— Gorga et al 5th Percentile
A '1 —v— Gorga et al 95th Percentile
.1
0. _
<0 10
m
B
8 o -
3
’a
E
< -10 _
Lu
<
O
n.
o -20 —
-30
I I l l l l l
1000 2000 3000 4000 5000 6000 70008000

Frequency (Hz)

37

Participant WS003’s pure-tone thresholds were within normal limits bilaterally.
His DPOAE amplitudes in the frequency range of 1,500 to 3.000 H2 and above 5,000 Hz
were indicative of normal hearing in both ears. Forty-six percent of the DPOAE
responses from the right ear and 42% of the responses from the left ear fell within the
ambiguous range.

Participant WSOO4’s pure-tone thresholds indicated bilateral mild-to-moderate
hearing loss across the stimulus frequency range. His DPOAE amplitudes between 1,500
and 3,000 Hz were indicative of normal hearing and DPOAE amplitudes above 5,000 Hz
were consistent with hearing-impaired ears. Forty—six percent of the DPOAE responses
from the right ear and 50% of the responses from the left ear fell within the ambiguous
range.

Participant W8018 demonstrated thresholds that rose from mild hearing loss (at
1,000 Hz) to normal-hearing range (at 2,000 Hz), and then sloped to mild hearing loss in
the right ear. She also demonstrated thresholds that sloped from mild-to-moderate hearing
loss (above 4,000 Hz) in the left ear. The DPOAE amplitudes in the frequency range of
2,000 to 2,500 Hz and at frequencies above 4,500 Hz in her right car were indicative of
normal hearing. The DPOAE amplitudes in the frequency range of 5,500 to 6,500 Hz in
her left car were consistent with hearing impaired ears. Fifty-four percent of the DPOAE
responses from the right ear and 75% of the responses from the left ear fell within the
ambiguous range.

Test-retest reliability
Test-retest reliability was assessed by comparing two sets of pure-tone threshold

data and DPOAE data for the youngest participant in the current study (WS018). Data

38

from the current study were compared to data obtained at the 2004 Williams Syndrome
Association Conference two months earlier. It is important to note that the subjects for
the study of Marler et a1. (2004) and the subjects for this project do not overlap (i.e.,
because the subject had follow-up assessment for this project, she was not included in the
conference screening data set reported).

Table 5 provides the pure-tone data comparison. Due to environmental constraints
(i.e., ambient noise levels), the criterion for passing a hearing screening at the conference

was 20 dB HL. A threshold search was conducted only for those frequencies at which the

 

individual failed the screening. Differences between thresholds obtained at the
conference and thresholds obtained at the clinic were within 5 dB HL. This is considered
to be typical test-retest variation (Harrell, 2002).

Table 5. Participant WS018’s air-conduction thresholds obtained from hearing screening
and diagnostic evaluation.

 

 

Right ear (dB HL) Left ear (dB HL)
Freq. (Hz) 500 1k 2k 4k 6k 8k 500 1k 2k 4k 6k 8k
5:;ference Pass Pass Pass 30 25 Pass 25 Pass Pass 30 45 40

2:30” 20 15 10 25 25 15 25 15 15 25 40 40

“Pass” equals to a response to 20 dB HL stimuli.

Figure 4 provides the DPOAE data comparison. The DPOAE parameter settings
in Marler et al. were the same as the current study. These two sets of data show a similar
pattern and are consistent with audiometric findings. Sladen, Lamb and Hall (1996, as
cited in Hall, J. W. III, 2000) reported that the intrasubject DPOAE amplitude variability
was typically between 6 and 7 dB and as low as 3 dB SPL. The intrasubject amplitude
variance for DPOAE by F2 frequency was within the dB range reported by Sladen et al.
(1996) for 16 of 24 data points, including all of the points in the region between 4,000

and 6,000 Hz, the region in which data are consistent with hearing loss.

39

Figure 4. DPOAES of participant W8018 obtained from hearing screening and diagnostic
evaluation.

--—- DPOAE Noise Floor

25 _ —I —— Gorga 5th Percentile for Hearing Impaired Ears
-- X-- W818 LE Conference DPOAE

2° ‘ —o—ws1e RE Conference DPOAE

15 1 '* ‘V- Gorga 95m Percentile for Normal Hearing Ears

o-o—°~o\
00,

Absolute DPOAE Intensity (dB SPL)

 

 

 

I ' Tfi‘ .fi—fi' ' ‘7 1—
1000 2000 3000 4000 5000 6000 70008000
F2 Frequency (Hz)
: *7 DPOAE Noise Floor
25 _ * l — Gorga 5th Percentile for Hearing Impaired Ears
-- X-- W818 LE Clinic DPOAE
2°] —0— wsw RE Clinic DPOAE
15 .1 —V— Gorga 95th Percentile for Normal Hearing Ears

Absolute DPOAE Intensity (dB SPL)

  

.30 ___ v... __ _ _. *_:

—I' l_‘“ T' "'1” ‘-
1000 2000 3000 4000 5000 6000 70008000

 

FZFrequncy (Hz)

40

Loudness discomfort level (LDL) rating

LDL rating data were obtained from four adult participants (WS001, WSOOZ,
WSOO3, and WSOO4). The rating system was changed from a three-item scale to a five-
item scale after the data of Participant W800] were collected. Therefore, the LDL data
from WSOOl were excluded from the data analysis. The LDL data were not collected
from any of the children due to the participants’ fatigue and loss of attention to the task.
The data for WS002, WSOO3 and WSOO4 are shown in Table 6.

Table 6. Loudness discomfort level rating scale data for the adult participants

Speech noise stimulus level (dB HL) Multi-talker babble stimulus level (dB HL)
15 25 35 45 55 65 5 15 25 35 45 55 65

 

5
WSOOZ 2 2 3 3 3 5 l 2 3 3 5 5
W8003 l 3 4 3 5 4 5 2 2 5 5
WSO04 l 2 3 3 3 4 4 l 2 3 4

 

1=cannot hear; 2=too soft; 3=O.K.; 4=loud, but tolerable; 5:100 loud.

Participant WS002, who showed a mild sensorineural hearing loss at 8,000 Hz in
the right ear, and a mild-to-moderate sensorineural hearing loss above the 4,000 Hz range
in the left ear, rated the speech noise stimuli as “too loud” at 55 dB HL and the multi-
talker babble as “too loud” at 45 and 55 dB HL. Participant WSOO3, who showed hearing
within normal limits in pure-tone audiometry, rated the multi-talkcr babble as “too loud”
at 45 dB HL, but was inconsistent in identifying the discomfort level for the speech-noise
stimuli (i.e., rated 45 dB HL as “too loud,” but rated 55 dB HL as “loud, but tolerable”).
Participant WSOO4, who showed a bilateral mild-to-moderate sensorineural hearing loss,
rated both the speech noise and the multi-talker babble stimuli as “loud, but tolerable” at
65 dB HL. Due to the predetermined upper limit of 65 dB HL in this task, the investigator

could not determine the level that participant WSOO4 would have rated “too loud.”

41

.3. ‘-..---.§.A.'

"‘5

Of the three individuals who performed the LDL tasks, two (WSOO2 and WSOO4)
responded consistently to the stimuli and two (WSOO2 and WSOO3) demonstrated LDLs
lower than the predetermined upper limit. Although limited, these findings were
consistent with expectations prior to the initiation of the study.

The following unexpected findings were also observed. Participant WSOOZ
showed bilateral high-frequency sensorineural hearing loss, and her LDL was lower than
that of WSOO3, who showed pure-tone thresholds within normal limits. Participant
WSOO3 demonstrated inconsistent ratings of the stimuli. Participant WS004’s actual LDL
was presumably higher than the upper limit allowed by the research design.

Hyperacusis questionnaire

Hypersensitivity to sounds

During or after data collection, all of the parents of the participants returned
questionnaires regarding the individual’s responses to loud sounds and history of hearing
loss, and middle ear disease. All of them reported that their children were “bothered or
frightened” by certain sounds during childhood and that all of them, including those now
adults, were still “bothered or frightened” by these sounds when this survey was
conducted. The following items were those most commonly selected by the parents as the
sounds that cause the greatest discomfort: “firecracker (six out of seven),” “fire engine
siren (five out of seven),” and “power saw (four out of seven)” Additional sounds
selected by some parents as the sounds that caused the greatest discomfort to their

99 66

children were “motorcycle,” “loud auto muffler,” “electric drill,” “dog barking, lawn

mower,” “squeaking toys,” “hammering a nail,” and “food blender.”

42

The parents of three participants (WS001, WSOO3, and WSOl6) reported that the
discomfort level associated with loud sounds became reduced as their children grew up;
the parents of the remaining participants reported that the discomfort level remained the
same. Only the father of individual W8003 reported that he had looked for professional
help for his child’s hyperacusis. That parent noted that his child liked to play music and
did not complain about its intensity. The parent of participant WSOO4 reported that his
child likes car races, so he wears ear protection and forces himself to tolerate the loud
noises. When responding to a question focused only on “fear,” the parents of participant
WS001 and participant WSOO4 reported that these individuals continue to dislike the
types of sounds that were reported earlier (e. g., firecracker, fire engine siren, power saw),
but that these sounds no longer cause fear. The parents of the youngest participant
(WSOl8) reported that their daughter still had fear of these sounds; however, during the
experimental session, they stated that her hyperacusis had never been as disruptive as
reported by other parents of children with WS. The parents of the remaining adult and
child participants reported that fear of loud sounds was still an issue at the time this
survey was conducted.

The following descriptions of the participants’ most frequent responses to loud
sounds were noted in the parent reports. Six out of seven sets of parents reported that the
participant “covers ears with hands.” Five out of seven reported “cries,” five out of seven
reported “cringes” and four out of seven reported “says something like I don’t like it.” All
of the parents reported that the characteristics of sounds that most bothered the

participants were how loud the sound is and a sudden sound.

43

Hearing

Six of seven sets of parents reported that no diagnosis of permanent hearing loss
had been made before this study. The seventh, the parent of W8018 did not answer this
question. During the evaluation session, the parent of W8018 reported that her child
failed a hearing screening in kindergarten and that no follow-up diagnostic testing had
been done prior to the current study. She was unable to provide any additional details
regarding the hearing loss. The parents of W8018 also reported that hearing loss was not
a noticeable problem in their daughter. Participant WSOO4 reported a history of hearing
loss and rarely had middle ear infections; however, his parent reported that he had no
diagnosis of permanent hearing loss and that he was “obsessive about being deaf.” His
parent also reported (as noted above) that participant WSOO4 likes to attend car races and
forces himself to tolerate loud noise by using earplugs. Participant WSOO4 also reported
that he understands the importance of using hearing protection when exposed to noise
and that he uses earplugs to protect his hearing.

Middle ear infection

 

Two of seven sets of parents reported that their children (W8002 and WSOO3)
never had ear infections, and three additional sets reported that their children (W8001,
WSOO4, and W8018) rarely had ear infections. W8004’s parents reported that he never
had an ear infection in childhood, and rarely has one now..The remaining two sets of
parents reported that their children (W8016 and W8028) had recurrent ear infections
(several or constant) during childhood, but that they were less frequent as the participants

grew up.

44

CHAPTER 4
Discussion
Audiolggical assessment
At the initiation of the current project, the prevalence of hearing loss in
individuals with W8 had not been widely studied. Due to the characteristic of
hypersensitivity to sounds, most individuals with W8 have been assumed to have normal
or better than normal hearing. In fact, data reported by Ruangdaraganon et al. (1999) and
Johnson et al. (2001) have shown that individuals with W8 have a higher prevalence of
hearing loss (33%) than is demonstrated by the children ages 3 to 10 years (9 in 10,000)
(Van Naarden, Decoufle, and Caldwell, 1999). In addition, hearing screening and
DPOAE data obtained by Marler et al. (2004) during a Williams Syndrome Association
conference revealed that a surprising number of individuals with W8 (74% of those
examined) had poorer-than-expected auditory function. A report published by Cherniske
et al. (2004) during the course of the current study confirms and expands previous reports
of hearing loss in adults with W8. Cherniske et al. investigated multisystem function (i.e.,
cognitive, cardiovascular, musculoskeletal, gastrointestinal, endocrine, visual and
auditory systems functioning) in 20 adults with W8 over 30 years of age. Sixteen of these
20 adults had “standard audiological testing” (p. 256) in a hospital setting. Seventy-five
percent had high-frequency sensorineural hearing loss. Half of these hearing losses were
unilateral.
In the current study, five of seven participants had bilateral symmetrical

sensorineural hearing loss. The configurations were either hearing loss only in the high

45

frequency range or hearing loss across the entire stimulus range, with thresholds greater
(poorer) above 2,000 Hz than below 2,000 Hz.

Figure 5 compares the four adult participants’ air-conduction thresholds to the
median threshold data for the general population calculated using data and formulas
provided by ISO 7029-1984. The ISO 7029-1984 data provides the audiometric

information for the frequency range of 125 to 8,000 Hz from the otologically normal

 

1?
individuals aged range of 18 to 70 years. According to ISO 7029-1984, the criteria for
identifying otologically normal was “a person in a normal state of health who at the time ii
of testing is free from excess wax in the ear canals, is without known ear pathology and r

who has no history of undue exposure of noise” (p. 2). The report also provides formulas
for calculating the expected value of the median hearing threshold shift relative to a
group of persons aged 18 years. The median thresholds in Figure 5 were generated from
data sets selected according to each participant’s age and gender.

All of the air-conduction thresholds for individuals W800] and WSOO4 were
equal to or poorer than the median 180 7029-1984 thresholds. The pure-tone thresholds
of W8002 were equal to or poorer than the median thresholds with three exceptions. The
left ear threshold for 500 Hz was 1.6 dB better than the median and the thresholds for
both ears at 1,000 Hz were 1.83 dB better than the median. The data from W8003 were
equal or poorer than median thresholds with just two exceptions. Thresholds from both
ears at 2,000 Hz were 5 dB better than the median.

This data comparison shows that four of the adult participants had at least three
thresholds in each ear that were 15 to 55 dB poorer than would be expected, given age

and gender. For W800] and W8002, these differences were greatest above 2,000 Hz.

46

Figure 5. Comparison of the four adult participants’ air-conduction thresholds to expected
median thresholds. The median was calculated from data and formulas provided by ISO
7029-1984 according to each individual’s age and gender (0: Right ear air-conduction
thresholds; X: Left ear air-conduction thresholds; *: Median threshold data calculated
from ISO 7029—1984).

Frequency in Hz
250 500 1000 2000 4000 8000

-10
0
10
20
30
40
50

60
70

Hearing thresholds in dB HL (ANSI 1989)

 

W800] (37 y/o, male)

Frequency in Hz

10 250 500 1000 2000 4000 8000

Hearing thresholds in dB HL (ANSI 1989)

 

W8002 (29 y/o, female)

47

 

Figure 5 (continued). Comparison of the four adult participants’ air-conduction thresholds
to expected median thresholds. The median was calculated from data and formulas
provided by ISO 7029-1984 according to each individual’s age and gender (0: Right ear
air-conduction thresholds; X: Left ear air-conduction thresholds; *: Median threshold data
calculated from ISO 71129-1984).

Frequency in Hz
250 500 1000 2000 4000 8000

 

-10

 

 

10
20 .

 

 

 

 

 

8

 

 

70
80

 

 

Hearing thresholds in dB HL (ANSI 1989)

 

100
110

 

 

 

 

 

 

 

 

 

WSOO3 (17.5 y/o, male)

Frequency in Hz
250 500 1000 2000 4000 8000

0 L gaL

 

 

 

 

 

 

 

 

 

 

la

 

 

 

 

Hearing thresholds in dB HL (ANSI 1989)
8
r
\.
A
9

 

 

 

 

 

 

 

 

 

mm (26 y/o, male)

48

 

Thresholds for WSOO4 were 30 to 55 dB poorer than would be expected given age and
gender at all the test frequencies.

Figure 6 compares the three child participants’ air-conduction thresholds to the
median threshold data that was reported by Holmes, Niskar, Kieszak, Rubin, and Brody
(1994). Holmes et al. obtained hearing thresholds in the frequency range of 500 to 8,000
Hz from 6,166 children ages 6 to 19 years in the Third National Health and Nutrition
Examination Survey. In the study of Holmes et al., physical examinations and home
interviews were performed to determine test exclusions (e.g., draining ears, colds, sinus
problems, or exposure to loud noise over the past 24 hours). This study provides the
mean and median thresholds by ear, gender, frequency and age group (6 to 11 years, 12
to 19 year). The median thresholds from the age group that matched each child
participant’s age were used for data comparison in Figure 6.

All of the air-conduction thresholds for individual W8016 and W8018 were
poorer than'the median thresholds reported by Holmes et al. The pure-tone threshold at
8,000 Hz in the right ear of participant WSO28 was 8 dB better than the median
thresholds for the female ages 7 to 11 years in Holmes et al. Only one pure-tone threshold
at one frequency in one participant was observed to be better than those of normal
hearing age-peers.

With the exception of isolated thresholds from three individuals (W8002, WSOO3,
and W8028), all the participants in the current study showed pure-tone thresholds poorer
than would be expected from age peers in the general population. Five of the seven

participants in the current study showed bilateral sensorineural hearing loss. These

49

 

findings indicate that the prevalence of hearing loss in individuals with W8 is greater
than previously reported.

Although six of seven participants in the current study had no prior documented
diagnosis of permanent hearing loss, four of these six participants showed sensorineural
hearing loss. In addition, parental reports in the current study showed that most (six out
of seven sets) of the participants’ parents were not aware of the possibility of hearing loss
in individuals with WS. They reported assumptions that their family members with W8
would not have hearing impairment because of their oversensitive responses to sounds.
These findings provide clear evidence that hearing impairment in individuals with W8
has often been overlooked.

Figure 6. Comparison of the three child participants’ air-conduction thresholds to the
median thresholds reported by Holmes et al. (1994). The median was selected according to
each participant’s age and gender (0: Right ear air-conduction thresholds; X: Left ear air-
conduction thresholds; *: Median threshold data reported by Holmes et al.).

Frequency in Hz
250 500 1000 2000 4000 8000

-10 5 L

 

 

 

 

 

.2 ;
,L/XQ 0
:\x

J
Y

10 f
20

 

   

 

 

 

 

 

 

 

 

 

 

 

 

Hearing thresholds in dB HL (ANSI 1989)

 

 

 

 

 

 

 

 

 

110
W8016 (7 y/o, male)

50

 

Figure 6 (continued). Comparison of the three child participants’ air-conduction thresholds
to the median thresholds reported by Holmes et al. (1994). The median was selected
according to each participant’s age and gender (0: Right ear air-conduction thresholds; X:

Left ear air-conduction thresholds;

10

888

60
70

Hearing thresholds in dB HL (ANSI 1989)

100
110

Hearing thresholds in dB HL (ANSI 1989)

250 500
0

*: Median threshold data reported by Holmes et al.).

Frequency in Hz

1000

2000

4000 8000

 

 

 

 

4"?”

 

E/CP

 

X/

Jam

I\-

 

 

 

X

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

250 500

W8018 (7.5 y/o, female)

Frequency in Hz

1000

2000

 

4000 8000

 

.

I

I

I
_,_.__.'.._...-—

9

:

I

l

 

 

A

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

W8028 (11.5 y/o, female)

5]

Previous studies have shown the impact of hearing impairment on children's
language development, academic achievements and social behaviors. Davis, Elfenbein,
Schum and Bentler (1986) investigated the effects of degree of hearing impairment, age,
and other factors on intellectual, social, academic, and language behaviors on 40 children
with mild to moderately severe hearing impairment. According to Davis et a1. (1986)
“children with any degree of hearing loss appear to be at risk for delayed language
development of verbal skills and reduced academic achievement” (p. 61). The researchers
also reported that the two children with the mildest hearing loss in their study
demonstrated some of the greatest vocabulary delays (i.e., 3 to 4 years on the Peabody
Picture Vocabulary Test - Revised).

Bess, Dodd-Murphy and Parker (1998) defined minimal sensorineural hearing
loss for three groups: unilateral sensorineural hearing loss (USHL, pure-tone average of
20 dB HL or greater in the impaired ear), bilateral sensorineural hearing loss (BSHL,
pure-tone average between 20 dB and 40 dB HL bilaterally), and high-frequency
sensorineural hearing loss (HFSHL, air—conduction thresholds greater than 25 dB HL at
two or more frequencies above 2,000 Hz in one or both ears). They reported that 5.4 % of
the children in the schools they worked with exhibited minimal sensorineural hearing loss
(MSHL) and that 37% of children with MSHL failed at least one grade compared to a
district rate of about 3%. Two of the three child participants (W8018 and W8028) in the
current study met the Bess et a]. definition of MSHL. Participant W8018 exhibited
HFSHL in her left ear and participant W8028 demonstrated BSHL. Not only did these
two child participants exhibit MSHL, but also two of the four adult participants (W8001

and W8002) demonstrated HFSHL. It is clear that because of MSHL, these two child

52

Fri—fl

 

participants could be experiencing greater difficulties in school than do their normal-
hearing age-peers. Both the Davis et al. and Bess et al. studies revealed the importance of
identification of hearing loss in general populations of children; children with W8 would
be no different.

It is important to note that minimal sensorineural hearing loss could not be
revealed by standard school hearing screenings recommended by the ASHA Audiology

Panel (1997) which uses a 20 dB HL presentation level for pure-tone stimuli at 1,000,

4J1 In m—fiy

2,000 and 4,000 Hz. Therefore, without a full hearing evaluation in a clinical setting, the

 

possibility of ignorance of hearing loss is high. L

The current study showed a high prevalence of hearing loss in the individuals
with W8 and low awareness of this hearing loss among their parents. Two of the three
child participants in the current study demonstrated minimal sensorineural hearing loss.
There is also evidence that minimal sensorineural hearing loss could have been missed by
standard school hearing screenings. Thus, an annual hearing evaluation should be
included in the routine test of the individuals with WS. This is especially important
because we do not yet have evidence of age-of-onset patterns for this population.
Otoacoustic emission data

The DPOAE measures of two (W8001 and WSOO4) of the five participants with
bilateral hearing loss showed significantly reduced DPOAE amplitudes relative to data
provided by Gorga et a1. (1997) for the high frequency range (i.e., from 4,000 to 6,000
Hz). Reduced DPOAE amplitudes, consistent with impaired outer hair cell function, were

observed from 4,000 to 7,000 Hz in participant W800] and above 5,000 Hz in participant

 

WSOO4. Marler et al. (2004) recently reported that 74% of their participants showed

53

 

reduced DPOAE amplitude in the frequency range of 3,500-6,000 Hz. Impaired outer
hair cell function results in sensorineural hearing loss. Therefore, the findings of both the
current study and the Marler et al. study are consistent with the findings of sensorineural
hearing loss (75%) reported by Cherniske et a1. (2004).

Only one participant in the current study demonstrated hearing within normal
limits. He did not demonstrate the absence of otoacoustic emission responses reported by
Johnson et al. (2001). In the five participants who demonstrated thresholds within normal
limits in the low and/or mid-frequency range, only a single isolated DPOAE in those
ranges was consistent with hearing-impaired ears. None of these participants
demonstrated the absence of OAE responses reported by Johnson et al. (2001).

Loudness discomfort level (LDL) rating

The current design of the LDL measure for this project did not allow for complete
LDL measurements in the adult individuals with WS, and no data were collected for the
children. The relation between hearing thresholds and LDL could not be investigated due
to the small number of participants in this study. However, two out of three participants
in this task assigned a rating of “too loud” at levels much lower than those expected from
the general population.

The pictures and descriptions for LDL measures in the current study worked well
in terms of instruction comprehension. The participants in this task were able to use these
pictures adequately to express their feelings about the stimuli.

In a recent critical review of the most comfortable level (MCL) and LDL
literature, Punch, Joseph, and Rakerd (2004) cited documentation that prior exposure to

loud stimulus levels (i.e., use of a descending approach) tends to increase the MCL. This

54

 

literature also shows how an auditory referent influences the measures of MCL and LDL.
A lack of an auditory referent in the current research design (i.e., random presentation of
stimuli) may have contributed to the inconsistent responses that were observed from
participant WSOO3. An ascending approach should be included in any future research
design in order to provide an auditory referent and to help individuals with W8 overcome
the fear of loud stimuli.

The approach in the current study was flawed in that it did not include the option
to continue increasing stimulus level to the point that yielded a rating of “5” In order to
investigate whether individuals with W8 have a lower tolerance for loud sounds than
their normal age peers, future studies should emphasize conducting LDL measures on a
large group of individuals with W8, the range of stimuli used should not be
predetermined, and an ascending method should be used.

Hyperacusis questionnaire

All of the parents of the individuals with W8 reported that their children were
bothered by loud sounds in the past and were still sensitive to loud sounds at the time of
data collection. All of the participants were reported to exhibit a fear response to loud
sounds in childhood, and three of them (two adults and a child) have reportedly outgrown
their fear to sounds.

Parental reports showed that the prevalence of recurrent otitis media in the current
study (two of seven individuals) was lower than the rates for individuals with W8
reported by Klein et al., 1990 (61%; ages 1 to 28 years) and Van Borsel et al., 1997
(54%; ages 1 to 45 years); however, it was close to the rate reported for normally

developing children ages 1 to 17 years (26.9%, Lanphear, Byrd, Auinger, & Hall, 1997).

55

 

 

 

Thus the prevalence of recurrent otitis media in individuals with W8 was not as high as
reported in previous studies. However, it is possible that the data in this study may not
represent the general population of individuals with W8 due to the small number of the
participants.

Although the prevalence of recurrent otitis media was not as high as reported in
previous studies, it was consistent with the tympanometric findings in the current study.
Five of the participants demonstrated normal middle ear function in tympanometry
during data collection. The other two participants either exhibited middle ear stiffness or
were not willing to be tested in this task. Although tympanometry could not be done in
these participants, parental reports revealed a history of recurrent otitis media and a fear
of probe placement resulting from poor experiences with middle ear disease treatment in
the past. Recurrence of otitis media could have not only contributed to conductive
hearing loss, but also led to minimal-to-mild unilateral or bilateral sensorineural hearing
loss (Bess et al., 1996; Hunter, Margolis, Rykken, Le, Daly, and Giebink, 1996). Two of
seven participants (W8016 and W8028) in the current study were reported as having
recurrent otitis media; however, their parents also reported that they were not aware of
the presence of hearing loss in the past. Therefore, it was not possible to confirm that
recurrent otitis media contributed to their hearing loss. The relation between recurrent
otitis media and high-frequency sensorineural hearing loss in individuals with W8 has not
yet been investigated. Thus future research into the cause of high-frequency hearing loss
in individuals with WS should also include an investigation of the potential contribution

of otitis media.

56

Evaluation procedures

The current study showed that it is possible to obtain reliable behavioral
thresholds from individuals with W8. All of the adult participants in the current study
were able to participate in conventional pure-tone audiometry by raising a hand to
respond to the pure-tone stimuli. The modified audiological assessment recommended by
Kile (1996) and Dille (2003) for testing individuals with Down syndrome can be used for
testing children with W8 (e.g., use of visual reinforcement to help children with W8 pay
attention to the task). Another approach that would be useful would be the gradual

acclimatization to the assessment procedures that was used in the data collection of 1

 

participant W8028. Modifications to standard procedures included letting the participant
wear earphones in an environment where she felt comfortable, use of conditioned play
audiometry outside the booth to help the participant practice how to respond to stimuli,
use of VRA to help the participant become familiar with the testing booth, and finally, a
shift from VRA to standard conditioned play audiometry in the booth. This process
helped W8028 overcome the fear of earphone placement and led to reliable responses
during hearing assessment. This approach would require more time than is typical in
clinical settings; therefore, it will be necessary to plan ahead both for time in the clinic
and in home activities. Perhaps practice at home with earphones (e.g., to listen to music)
prior to hearing assessment can help individuals with W8 to get used to earphone
placement.

DPOAE measures should be included in the assessment of children with W8,
especially when behavioral thresholds (pure-tone thresholds) cannot be obtained. Due to

the frequent occurrence of otitis media in children with W8, tympanometry should be

57

also be included as a routine test in the audiological evaluation. Two child participants
(W8016 and W8028) in the current study exhibited fear or dislike of the probe placement
for tympanometry and DPOAE measures, or dislike of the placement of the earphones for
pure-tone audiometry. Audiologists in the clinical setting or in future research should be
cautious about this tendency and leave tympanometry and DPOAE measures to the end
of the hearing evaluation in order to limit the impact of these fear responses on other
aspects of hearing assessment. In addition, standard headphones should be used instead of
insert phones during for pure-tone audiometry.
Summary and conclusion

Due to the small number of individuals evaluated, the data from the current study
should be considered cautiously. Mild-to-moderate, sloping. sensorineural hearing loss in
the high-frequency range (above 4,000 Hz) is the major finding of the current study. This
finding supports ongoing reports of a high prevalence of hearing loss among children and
adults with W8 and strongly challenges the historical assumption that individuals with
W8 have better than normal hearing. The empirical evidence presented here demonstrates
that reports of hypersensitivity to sounds do not justify a conclusion that overall hearing
is intact or better than normal in individuals with WS. It is also clear that parents of
individuals with W8 in the current study had low awareness of hearing impairment in
their children.

Bess et al. (1998) revealed the impact of sensorineural hearing impairment even at
the minimal levels demonstrated by two of the three child participants in this study. An
annual hearing evaluation including pure-tone audiometry, tympanometry, and DPOAE

measure is strongly recommended for this population. Use of modified assessment

58

strategies can help children with W8 overcome the fear of probe or earphone placement
and enable them to pay attention to the task. Once the hearing impairment is diagnosed in
individuals with W8, appropriate assistance (e.g., hearing aids, classroom amplification)
should be provided. Individuals with mild-to—moderate, sloping, sensorineural hearing
loss in the high-frequency range (e.g., W800], W8002 and W8018) are not candidates
for hearing aid fitting because hearing aids provide very limited benefit above 4,000 Hz
frequency range. For these children, classroom amplification systems that increase the
signal-to-noise ratio should be explored as a means to provide the teacher’s voice at a
level well above the classroom noise. Children with greater degrees of hearing
impairment who are hearing aid users would also be expected to benefit from such
systems. Although the cause and the mechanism of hearing loss in individuals with W8
are still unknown, it is important to address fully and investigate the impact of hearing

loss on these children’s language development and academic achievement.

59

 

- j: 1"
1'

 

APPENDICES

60

APPENDIX A

Hyperacusis Questionnaire

61

Auditory processing in W8 W8 Questionnaire
NICHD R03 HD 44468-1 MSU IRB# 02-534

Child’s Name: Date of Birth:
Gender:

 

 

Please answer the following questions about your child’s past and present behavioral
responses to loud sounds. In Column A, please answer according to the period (the
child’s age) when the hyperacusis was most severe (disruptive to his/her daily life and to
the life of the family). In Column B, please answer according his/her present response to
loud sounds.

 

 

Column A (past) Column B (present)

la. Was your child presently frightened lb. Is your child presently frightened or
or bothered by certain sounds? bothered by certain sounds?
YES NO YES NO

2a. If your child was ever fearful of 2b. If your child “outgrew” the fear of
loud sounds, at what age did this loud sounds, so what age did this
begin, and was there an age when it become apparent?
was the most disruptive to his/her
daily life?

 

 

 

 

 

 

 

 

3a. How often had your child had ear 313- HOW often has your Child had ear

infections? infections?
a. _ Never a. _ Never
b. __ Rarely, one or two times 13- __ Rarely. one or two times
c. __ Several, over a few years C- __ Several, over a few years
treated with medication. treated With medication.
(1. _ Constantly, requiring d- _ Constantly, requiring
medication and eventually tubes mebdication and eventually
tu es

4. Had your child been diagnosed as
having a permanent hearing loss?
YES NO

 

 

 

62

IF THE ANSWERS TO QUESTIONS 1 AND 2 WERE “NO” (NO PROBLEMS

WITH LOUD SOUNDS) - STOP HERE. OTHERWISE CONTINUE.

 

 

Column A (past)

5a. On a scale of 1 to 5, in the right

column, please rate the degree of
- discomfort each sound caused your

child [where 1=least discomfort and
7=greatest discomfort]. If your child
has never been exposed to the sound,
mark N/E (left column for “no
exposure”).

N/E Degree

Airplane
Motorcycle

Loud auto muffler
Garbage truck
Fire engine siren
Hammering a nail
Power saw
Electric drill
Telephone ringing
Firecracker
Squeaking toys
Dog barking
Lawn mower
Playground noise
Loud music
Vacuum cleaner
Food blender
Train whistle

TV at normal volume level
Other, please specify below

 

6a. How (Lid your child react to above
noises? (You can choose more than
one type of reaction.)

a. Cover ears with hands

b. Cries

c. Says something like “it
hurts my ear”

(1. Says something like “I

don’t like it”

 

Column B (present)

5b. On a scale of 1 to 5, in the right
column, please rate the degree of
discomfort each sound causes your
child [where 1=least discomfort and
7=greatest discomfort]. If your child
has never been exposed to the sound,
mark N/E (left column for “no
exposure”).

N/E Degree
Airplane

Motorcycle

Loud auto muffler
Garbage truck

Fire engine siren
Hammering a nail

Power saw

Electric drill

Telephone ringing
Firecracker

Squeaking toys

Dog barking

Lawn mower

Playground noise

Loud music

Vacuum cleaner

Food blender

Train whistle

TV at normal volume level
Other, please specify below

 

6b. How does your child react to above
noises? (You can choose more than
one type of reaction.)

 

h. Cover ears with hands

i. Cries

j. Says something like “it
hurts my ear”

k. Says something like “I

don’t like it”

 

 

63

 

 

Column A (past)

Run away from sound
Cringes
Other, please specify

 

below

 

 

7a. In general, the most important
characteristics of the sounds that
bothered your child M (you can
check more than one if necessary).

 

a. How loud the sound is

b. A low pitched sound like
an air conditioner

c. A high pitched sound
like a squeaky wheel

(1. A sudden sound

e. Reverberated sounds

f. Other

 

8a. On a scale of 1 to 5 (where 1 is
minimal discomfort and 5 is severe
discomfort), how would you
categorize your child’s hyperacusis
{gt—its mogprominent periom
his/her lite? Please circle the
appropriate number.

1 2 3 4 5

minimal severe
discomfort discomfort

 

Column B (present)

1. Run away from sound

m. Cringes

n. Other, please specify
below

 

 

7b. In general, the most important
characteristics of the sounds that
bother your child w (you can
check more than one if necessary).

a. How loud the sound is

b. A low pitched sound like
an air conditioner

c. A high pitched sound
like a squeaky wheel

(1. A sudden sound

e. Reverberated sounds

f. Other

 

8b. On a scale of l to 5 (where l is
minimal discomfort and 5 is severe
discomfort), how would you
currently categorize your child’s
hyperacusis? Please circle the
appropriate number.

1 2 3 4 5 ;

minimal severe
discomfort discomfort

 

9. Did you seek professional help for your child’s hyperacusis?

YES NO

10. Are these any circumstance or behavior related to your child’s progress to sounds,

that you think important, but have not been checked in this questionnaire?

Completed by

Date

 

 

Relation

 

Questionnaire was adaptedfrom Klein et a]. (1990).

 

APPENDIX B

Individual Data from Immitance Measures

65

Table 7. Individual data from immitance measures.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Static admittance Ear-canal volume Gradient
(mmho) (ml)

Right Left Right Left Right Left
W800] 0.5 0.4 2.1 1.8 0.4 0.5
W8002 1.1 1.0 0.9 1.0 0.7 0.7
WSOO3 0.3 0.4 0.8 0.9 0.5 0.5
WSOO4 0.7 0.6 1.8 1.7 0.5 0.5
W8016 NP CNE 0.4 CNE CNE CNE
W8018 0.3 0.2 0.7 0.7 CNE CNE
W8028 CNE CNE CNE CNE CNE CNE

 

NP = No peak. CNE = Could not evaluate.

66

 

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