THE RELATIONSHIPS AMONG SPEECH RECEPTION THRESHOLD, AUDITORY DISCRIMINATION, SPEAKER INTELLIGIBIUTY, AND THE‘TOTA’L NUMBER OF ARTICULATION ERRORS IN A GERIATRIC POPULATION Thesis for the Degree of Ph. D. MICHIGAN STATE UNIVERSITY HOWARD H. ZUBICK 1969 h LIBR A. R Y Mldligafi. $33!? 6??!le m- THESIS Ufliv This is to certify that the thesis entitled THE RELATIONSHIPS AMONG SPEECH RECEPTION THRESHOLD, AUDITORY DISCRIMINATION, SPEAKER INTELLIGIBILITY, AND THE TOTAL NUMBER OF ARTICULATION ERRORS IN A GERIATRIC POPULATION presented by Howard H. Zubick has been accepted towards fulfillment of the requirements for Ph D , , degree in Audiology 6: Speech Sciences \/\ id 4% x A - f‘ <';._,C;\ Major professor Date //’éaié? 0-169 ’ emomc av P" . mm; a so 3' {I III auox mum me. I I II lIII l I ll ‘1 Il ll I‘Q 0‘ l..|ll' ll!!! Ell l'tll’lvll'! ABSTRACT THE RELATIONSHIPS AMONG SPEECH RECEPTION THRESHOLD, AUDITORY DISCRIMINATION, SPEAKER INTELLIGIBILITY, AND THE TOTAL NUMBER OF ARTICULATION ERRORS IN A GERIATRIC POPULATION by Howard H. Zubick This study was concerned with the relationships among speech discrimination, articulatory precision, and speaker intelligibility. An objective means was needed to determine from scores obtained on a routine test of discrimination that point at which articulation and intelligibility begin to show signs of deterioration. It was felt that if these relationships could be clearly demonstrated, the audiologist concerned with rehabilitation would be in an improved position to predict the effects of discrimination loss on speech production. Twenty-four adults over the age of sixty having inter- weaving air and bone conduction thresholds participated in the study. The subjects were divided into four experimental groups of six individuals each, representing four levels of discrimination scores: 90-lOO%, 80-89%, 70-79%, and 60-69%. The subjects were placed in groups on the basis of discrimination scores which they achieved after having undergone pure-tone air and bone conduction and speech reception threshold testing. Selected items of a standardized Howard H. Zubick test of articulation were then administered to each subject by a panel of three judges. The subjects were then obliged to record selected lists of a multiple-choice intelligibility test; these recordings were subsequently played to a panel of eight listeners. It was found that as discrimination scores decreased, there was an increase in the total number of articulation errors. A significant increase was found in the total number of articulatory errors between the 90-100% and the 80-89% levels, and between the 80-89% and the 70-79% levels. A significant increase was not found in the total number of articulatory errors between the 70-79% and the 60-69% levels. The most common articulatory error was distortions followed by substitutions and then omissions. It was also found that speaker intelligibility ratings decreased as discrimination scores worsened. The discrimin- ation levels immediately adjacent to each other showed no significant difference with respect to intelligibility scores. However, all other group comparisons revealed significant differences, a fact leading to the conclusion that individuals with lowered discrimination scores will have less intelligible speech. Intelligibility scores and the total number of articu- latory errors were found to be significantly related. Individuals possessing high intelligibility ratings were those found to have the least number of articulatory errors. Howard H. Zubick Individuals with the greatest number of articulatory errors were those found to be the least intelligible. The importance of the discrimination score in the routine hearing evaluation was stressed in the light of its possible clues to needed rehabilitative measures necessary for the preservation of articulatory precision and speaker intelligibility. THE RELATIONSHIPS AMONG SPEECH RECEPTION THRESHOLD, AUDITORY DISCRIMINATION, SPEAKER INTELLIGIBILITY, AND THE TOTAL NUMBER OF ARTICULATION ERRORS IN A GERIATRIC POPULATION By Howard Hf Zubick A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Audiology and Speech Sciences 1969 TABLE OF CONTENTS LIST OF TABLES. . . . . . . . . . . . . . . LIST OF FIGURES . . . . . . . . . . . . . . Chapter I. INTRODUCTION. . . . . . . . . . . . . Purpose of the Study. . . . Importance of the Study . . Definition of Terms . . . . Organization of the Report. II. REVIEW OF THE LITERATURE. . . . . . . Hearing Loss: A Function of Aging. Speech: A Function of Hearing and Discrimination. . . . . . . . Aural Rehabilitation of the Aged Patient summary 0 O O O O O O O O O O O O 0 III. EXPERIMENTAL PROCEDURES . . . . . . . Selection and Grouping of Subjects. Equipment and Materials . . . . . . Procedures 0 O O C O C C O O O O O 0 IV. RESULTS AND DISCUSSION. . . . . . . . Results of Analyses of Group Differences. Results of Analyses of the Intercorrelation of Test Items. . V. SUMMARY AND CONCLUSIONS . . . . . . . Conclusions . . . . . . Implications for Further Research . BIBLIOGRAPHY. o o o o o o o o o o o o o o 0 ii iv vi Page TABLE OF CONTENTS - Continued APPENDIX A. O O O O O O O O 0 APPENDIX B. . . . . . . . . . iii Table LIST OF TABLES Grouping of subjects as determined by discrimination scores in percent achieved on the Northwestern University Auditory Test No. 6. O C C O O O O O .9. O O O O 0 Selected items from the Templin-Darley Test of Articulation with accompanying phonetic symbols for each test sound. . . Summary of Kruskal-Wallis one-way analysis of variance comparing four levels of discrimination. . . . . . . . . Summary data for Mann-Whitney U tests performed to determine individual differences between four levels of discrimination. . . . . . . .‘. . . . . . Summary of Kruskal-Wallis one-way analysis of variance comparing four levels of discrimination and speech reception threshold . . . . . . . . . . . Summary data for Mann-Whitney U tests performed to determine whether speech reception threshold differed as a function of specific levels of discrimination. . . . . . . . . . . . . . Summary for Kruskal-Wallis one-way analysis of variance comparing four levels of discrimination and the total number of articulatory errors . . . . . . iv Page 49 59 69 70 71 71 73 LIST OF TABLES - Continued Table 8. 10. 11. Summary data for Mann-Whitney U tests performed to determine whether the number of articulatory errors differed as a function of specific levels of discrimination. . . . . . . . . . . . . . Summary of Kruskal-wallis one-way analysis of variance comparing four levels of discrimination and speaker intelligibility . . . . . . . . . . . . . Summary data for Mann-Whitney U tests performed to determine whether intelligibility differed as a function of specific levels of discrimination. . . Summary of Spearman Rank Order Correlation Coefficient relating speech reception threshold, discrimination, speaker intelligibility, and the total number of articulation errors . . . . . . Page 73 77 77 80 LIST OF FIGURES Figure l. Octave band analysis of sound treated room utilized in sound field testing of speech reception threshold and speech discrimination. . . . . . . . . . Mean air conduction thresholds for subjects achieving discrimination scores between 90 and 100 percent (Level 1) . . Mean air conduction thresholds for subjects achieving discrimination scores between 80 and 89 percent (Level 2). . . Mean air conduction thresholds for subjects achieving discrimination scores between 70 and 79 percent (Level 3). . . Mean air conduction thresholds for subjects achieving discrimination scores between 60 and 69 percent (Level 4). . . vi Page 50 52 53 5h 55 CHAPTER I INTRODUCTION The study of oral communication between beings is the study of man himself. Hudson tells us that "regardless of age, man’s ability to control his environment, or to adapt to his environment, depends upon his ability to communi- cate."l Never before in the history of man has his ability to communicate with others been so vital a link in his attempt to survive. Hundreds of thousands of years ago when prehistoric man roamed the earth his chief means of survival was based upon his ingenuity and brute strength. Gradually, as man became more and more of a gregarious crea— ture, a need was found for a means of communication with sufficient scope and structure to allow for an efficient transfer of information. Oral communication via the spoken word became the universally accepted method of interaction. lAtwood Hudson, "Aging and Adequacy in Communication," in Social and Psychological Aspects of in , C. Tibbits and W. Donahue, editors. (New York: Columbia University Press, 1962), p. 615. Change has come rapidly to man and his civilization, and each day this turnover of knowledge and happenings is more rapid and devastating than was the previous one. The single word communication has ceased to be sufficient in the most menial of tasks. More than ever before, man is being pressured into verbal facility regardless of age or social circumstance. Today researchers are concerned with "effec- tive communication," a perfective term descriptive of a world startled daily with perfective happenings. Unfortunately not all beings are equal in communicative skills and, further, many are born with an unequal opportunity to acquire that ability. Others, after having achieved adequate verbal skills, tend to lose them through disease or the process of aging. Bloomer feels that "the degree to which a person maintains social adequacy depends in great part upon his retained facility in communication."1 It is the task of the speech and hearing scientist to research such communicative dilemmas and to provide the necessary habili- tative and rehabilitative measures indicated to bring these individuals into line with personal and social expectations. Certainly a great part of social acceptance is dependent upon an individual's ability both to receive and to convey infor- mation adequately. 1H. Harlan Bloomer, "Communication Problems Among Aged County Hospital Patients," Geriatrics, XV (1960), p. 291. Before delving any further into the problem of defective communication, it might be helpful to take a cursory view of the basic terminology. It has been stated by Johnson1 that communication is an attempt by one individual to convey some of his abstracted information to another. This second person, in this case a listener, abstracts certain ideas and evaluations of his own from the speaker's words. That information which the listener abstracts might not be related at all closely to what the original communicator had in mind. In this case a breakdown in the verbal interaction results, and the causative factors could be numerous. The foregoing is broken down into its component parts by Oyer2 who describes the communicative cycle as a system made up in the following way. He refers to the point of origin in the cycle as the "source," that to be communi- cated as the "code," the "channel” as that through which the message is sent, and finally the "receiver," that which picks up the code. Decoding of the message ensues, hope- fully followed by correct perception, understanding, and reaction. lWendell Johnson, People in Quandries (New York: Harper and Row, 1946), p. A76. 2Herbert J. Oyer, Auditor Communication for the Hard of Hearing (Englewood CIiEfs, New Jersey: Prentice- Hall, Inc., 1966), p. 15. In its typical application, the process of communica- tion receives little attention. However, should a break- down occur in this cyclical system, the wheels of progress rapidly grind to a halt. Failure to receive or interpret correctly even the smallest phonemic element may produce tragic results. This is not to say that all results of inefficient communications may produce catastrophic or even immediate consequences. It does say, however, that there may be a reaction to the communication, though it might not be one which is desired or is in fact desirable. Before continuing it would be advantageous to return momentarily to the term "effective communication." Oyerl feels that this term allows for only vague ideas as to how well or poorly the communicative cycle is operating. In applying these thoughts to the hearing handicapped he suggests further that rating scales be developed and data collected relative to hearing loss, speech intelligibility, and speech reception abilities. The benefits of such a scaling would be obvious. With normative data available on the aforementioned areas of speech and audition, it might be possible to develop a numbered scale which would indicate speaker efficiency relative to a particular type 1Herbert J. Oyer, "Research Needs in Aural Rehabili- tation," Aural Rehabilitation of the Acoustically Handicapped, Report of Semifiar Proceedings, Contract No. VRA 66-4I, Herbert J. Oyer, Chairman (East Lansing, Michigan: Depart- ment of Speech, Michigan State University, 1966), p. 137. and level of a specified hearing loss. If such a table were to be developed, such terms specified by Rosenbergl as "Speech Conservation" or "Speech Insurance" could take on a far reaching meaning in aural rehabilitation. There is presently no means by which to relate quantitatively and qualitatively specific types of hearing loss in adults to articulatory output and speaker intelligibility. Purpose of the Study Taking careful note of the literature regarding the close interaction existing between the sense of hearing and speech and language skills, the researcher set out to scale speaker intelligibility and articulatory precision as a function of varying levels of auditory discrimination scores. To begin with, the following questions were asked: 1. Does an individual's ability to discriminate the phonemes of speech affect his speech reception threshold? 2. Does an individual's ability to discriminate the phonemes of speech affect the total number of substitutions, distortions, and omissions in his speech? 3. Does an individual's ability to discriminate the phonemes of speech affect his intelli- gibility as a speaker? 1Philip E. Rosenberg, "Auditory Rehabilitation," Maico Audiological Series, I, No. 9 (l96H), p. 26. 4. Is there any relationship between speech reception threshold, discrimination, speaker intelligibility, and the total number of articulatory errors in an individual's speech? The following null hypotheses were devised in an attempt to answer the questions proposed in this study: 1. There are no significant differences among four specified levels of discrimination scores as measured by standardized phonetically balanced word lists. 2. There are no significant differences between specific levels of discrimination as measured by standardized phonetically balanced word ' lists and speech reception threshold. 3. There is no significant difference between specific levels of discrimination as measured by standardized phonetically balanced word lists and the total number of substitutions, distortions, and omissions. 4. There is no significant difference between specific levels of discrimination as measured by standardized phonetically balanced word lists and speaker intelli- gibility. 5. There are no significant correlations between speech reception threshold, dis- crimination, speaker intelligibility and the total number of articulatory errors in an individual's speech. Importance of the Study In reviewing the literature it becomes evident that there is a surprising lack of scientific research relative to the speech characteristics of the adult and geriatric population with a hearing loss. Oyer, in speaking of the lack of research in aural rehabilitation, states that aside from advances in amplification and surgical technique "I am not aware of any innovation that could be construed as a major breakthrough in the habilitation or rehabili- tation of the hearing handicapped."1 When specifically directing attention to research concerning the geriatric patient, one is amazed at the general disregard that has historically been accorded this ever growing population with regard to speech production. Lefevre2 indicates that the inability to communicate is the most frustrating problem for the older patient and generates more concern than does illness and disability. She further categorizes the communication problems of this population as follows: (1) hearing, (2) language, (3) artic- ulation, and (A) voice. In this instance Lefevre did not enumerate upon the possible relationship between hearing and articulatory imprecision. Levine further states that the geriatric patient is not only trying to adjust to increased physical disabilities and'limitations that have been imposed on him because of age, but he is also under the "continuing strain of trying not to misunderstand what's being said and the burden of trying not to be misunderstood.'.'3 lOyer, "Research Needs," p. 138. 2Margaret C. Lefevre, "Speech Therapy for the Geriatric Patient," Geriatrics, XII (1957), p. 691. 3Edna Levine, The Psychology of Deafness (New York: Columbia University Press, 1960), p. . Over the years, researchers have attempted to draw definitive lines between the sense of hearing and the acquisition of language and the production of speech. Oyerl points out that the hard-of-hearing child who lacks a degree of auditory stimulation suffers in his oral language skills on both an expressive and receptive level. Carhart2 indicates that when the hearing loss occurs in the later childhood years or in adulthood, the once normal discrimination abilities may become to some degree inade- quate. He further states that these individuals are obliged to base communicative judgments on distorted audi- tory patterns and that this often leads to progressively poor discriminative abilities. When an individual speaks of an ability to discrimi- nate, the implication is that a judgment or decision is being made between one item and an infinite number of other possibilities. Travis and Rasmus3 feel that speech sound discrimination calls for a judgment between meaningful speech sounds and that meaning is attached to particular sounds providing first that the individual hears the sounds lOyer, Auditory Communication, p. 56. 2Raymond Carhart, "Auditory Training," Hearing and Deafness, Hallowell Davis, editor (New York: Murray HiIl Books, Inc., 19h7), p. 282. 3Lee Edward Travis and Bessie Rasmus, "The Speech Sound Discrimination Ability of Cases With Functional Disorders of Articulation," Quarterly Journal of Speech, XVII (1931), p. 218. and second that he discriminates between them. The implication here is the existence of a listener model which, because of an acquired, long standing hearing loss, has deteriorated or changed over this period of time. Carhart1 states that when the ear reaches such a condition that it is no longer an effective monitor to verbal communication, the result is slow deterioration of speech. West2 adds that defective hearing is not just quantitatively related to defective speech but qualitatively as well in that one may infer from the speech sample the particular auditory deficiency peculiar to any given individual. The geriatric patient should be studied with respect to the hearing and speech relationship for a number of reasons. Initially, Hudson3 points out that the loss in hearing sensitivity appears to go hand-in-hand with the process of aging. Presbycusis, hearing loss due to aging, is, according to Hoople, ”the only ear condition which is more prevalent in elderly persons than in young people."“ lRaymond Carhart, "Conservation of Speech," Hearin and Deafness, Hallowell Davis, editor (New York: Murray Hill BooEs, Inc., 1947), p. 302. 2Robert west, "Speech and Hearing,” Volta Review, XXXVII (1935), p. 575. 3Atwood Hudson, ”Communication Problems of the Geriatric Patient," Journal of Speech and Hearinngisorders, XXV (1960), p. 240. “Gordon G. Hoople, "Care of Hearing in the Elderly," Geriatrics, XIV (1960), p. 106. 10 Since the geriatric population continues to increase in number, those in the field of aural rehabilitation must be prepared to meet the needs of those among the aged who experience a communicative disorder as a result of a hearing handicap. In reference to the problem, that of the relationship between discriminative ability and articulatory output, this aging segment of the population is of particular interest. It, more than any other experimental popula- tion, is likely to present a true picture of the effect of discrimination loss on speech over a long period of time. Further, since normative data are available as to what speech and articulation are or should be to begin with, an idea as to how speech deteriorates as a result of pro- gressive discrimination loss should be an aid to the clinician in planning and executing aural rehabilitative measures. This investigation proposes a study concerning four different levels of discrimination scores achieved by a geriatric population. The four levels selected were 90-100%, 80-89%, 70-79%, and 60-69%. Certainly it would be important and significant to know the type, degree, and progression of articulatory imprecision and unintelligibility as a possible end result of progressive loss of discrimi- nation ability demonstrated by these four different levels. 11 Definitions There are a number of terms common to the literature and which appear throughout this paper. These terms and their definitions follow: Discrimination.--According to Newby,l speech discrimination is referred to by the term articulation. He explains an articulation, or discrimination, test as "one which examines a patient's ability to discriminate among similar sounds or among words that contain similar sounds."2 In a clarifying statement, Davis refers to an articulation test as an indication of "the listener's ability to benefit by someone else's articulation of the words to which he is listening."3 The score is arrived at by administering a list of phonetically balanced words at a level determined by the individual's speech reception threshold. Newbyq suggests that these words be presented at least 40dB above speech reception threshold in order to achieve the patient's maximum score which is often referred to as "PB Max." 1Hayes A. Newby, Audiolo (2d ed.: New York: Appleton-Century-Crofts, , p. 213. 21bid., p. 21h. 3Hallowe11 Davis, "Audiometry," Hearing and Deafness, revised edition, Hallowell Davis and S. Richard Silverman, editors (New York: Holt, Rinehart and Hfinston, Inc., 1960), p0 189. “Newby, Audiology, p. 115. 12 This type of discrimination test should be differen- tiated from that typically used in determining the etiology of articulatory errors. These so-called tests of phonetic discrimination seek to determine the relationship between an individual's ability to discriminate among speech sounds and his degree of articulatory imprecision. The Templinl modification of the Travis-Rasmus2 test is one of the more common tests of phonetic discrimination. It requires a subject to make a judgment as to whether two nonsense syllables spoken by an examiner are the same or different. The test results are generally used as an indication of the need for discrimination training in the process of articulation therapy. This form of articulation testing will be discussed further in Chapter II, though it is the former type of discrimination testing that will be employed in the experimental procedure. Articulation.--With specific reference to speech, Wood states that articulation refers to "the production of individual sounds in connected discourse; the movement and placement during speech of the organs which serve to inter- rupt or modify the voiced or unvoiced air stream into lMildred C. Templin, "A Non-diagnostic Articulation Test," Journal of Speech Disorders, XII (1947), pp. 392- 396. 2Lee Edward Travis and Bessie Rasmus, "The Speech Sound Discrimination Ability," pp. 217-226. l3 1 Most attention is accorded the move- meaningful sounds." ment and placement of the active articulators including the lips, tongue, mandible, and soft palate. Van Riper and Irwin expand upon this definition stating that "articulation also refers to the acoustic impression, to the distinctness or acceptability of the speech sound."2 This addition is of vital importance to the present study since articulatory precision and speaker intelligibility will be judged by a panel of listeners. Intelligibility.--This term is regarded by Black3 as a listener evaluation. He states further that intelli- gibility implies a testing situation in which a quantita- tive score is derived. In addition, Black relates that "perfect intelligibility occurs when the symbols which a hearer writes on a paper correspond exactly to those on the paper of the speaker."4 The difference or discrepancy between the two lists would be indicative as to the 1Kenneth Scott Wood, "Terminology and Nomenclature,” Handbook of Speech Pathology, Lee Edward Travis, editor (New York: Appleton-Century-Crofts, Inc., 1957), p. 50. 2Charles Van Riper and John V. Irwin, Voice and Articulation (Englewood Cliffs, New Jersey: Prentice-Hall, Inc., 1958), p. 1. 3John W. Black, "Speech Intelligibility: A Summary of Recent Research,” Journal of Communication, XI (1961), p. 87. “Ibid., p. 87. 14 intelligibility of the speaker, provided that the listener and environmental conditions are controlled. Organization of the Report Chapter I has introduced the subject of articulation and intelligibility as a function of auditory discrimi- nation. From this broad field of study, the problem of the relationship between specific levels of discrimination and articulatory precision and speaker intelligibility was chosen. The terms relevant to the study were also defined and discussed. Chapter II reflects a comprehensive review of the literature concerning the areas of psychological changes in the geriatric patient and their effect upon aural rehabilitation, hearing loss as a function of aging, the effect of hearing upon speech production, and the general area of speech therapy in the aural rehabilitation program. Chapter III is concerned with subject selection, equipment, and experimental procedures. Chapter IV presents the results of the statistical analyses. They are examined in the light of the hypotheses described in Chapter I. Chapter V presents a summary of the present study. Conclusions are drawn, and on this basis, recommendations for further research are made. CHAPTER II REVIEW OF BACKGROUND LITERATURE This chapter presents a review of the important clinical and research literature pertinent to the present investigation. It begins with the known relationship existing between hearing loss and the process of aging and proceeds to delineate systematically this relationship into a firm basis for the understanding of auditory recep- tion and vocal expression. The focal point of the dis- cussion deals with the topic of auditory discrimination and how it determines the communicative dexterity of a given individual. The importance and relevancy of speech correction in an aural rehabilitation program is reviewed, and some degree of emphasis is directed at the complexity of problems confronting the audiologist in his attempt to rehabilitate the aging client. Hearing Loss: A Function of Aging There is presently a known relationship existing between decreased auditory sensitivity and functioning on one hand and increased age on the other. While this is far from being an innovative concept, it is an area of 15 16 research which has of late received a great deal of atten- tion from physician, social, and behavioral scientist alike. The increased span of life may be regarded as a major contributing factor to this recent surge of interest in the expanding geriatric population. égigg.--One of the basic problems encountered in the use of the term aging is in its comparative lack of a meaningful point of reference. Birrenl feels that while chronological age is related to aging, the two are not identical. Shock indicates that aging refers to the "progressive changes which take place in a cell, a tissue, an organ system, a total organism, or a group of organisms with the passage of time."2 With this serving as a basis, then, it would be difficult at best to correlate a parti- cular age with any specific occurrence such as a decrement in hearing sensitivity or discriminative ability. Fowler sums up the controversy very aptly by stating that "the aging process is so little understood that it is a weak hook upon which to hang the etiology of disorders or diseases occurring in older people."3 Apparently the 1James E. Birren, "Principles of Research on Aging," in Handbook of Aging and the Individual, ed. by James E. Birren (Chicago: University of Cfiicago Press, 1959), p. 6. 2Nathan w. Shock, Trends in Gerontology (2d ed.; Stanford: Stanford University Press, 1957), p. 99. 3Edmund P. Fowler, "Presbycusis," Annals of Otology, ‘Rhinology and Laryngology, LXVIII (SeptemEer, 1959), p. 764. l7 logical approach would be on a descriptive level within specified age ranges. Shockl maintains that time alters all living things in both structure and function; and when these changes occur along predictable lines, the process of aging is said to be taking place. Newby2 states that as the human organism begins to age, the sensory processes begin to show the general trend of deterioration. This is not to say, however, that the sensory deterioration accompanying aging is universal for all humans within a specified time zone. In addition to variations between individuals, there are also aging differences within the body tissues of any given individual. Fowler states that "tissues of the body show aging changes at different times and with differing "3 He further indicates that biologi- speeds and degrees. cally, aging is a spotty process. Birrenu cautions the researcher to the fact that such a great number of things happen to the aging organism that it is easy to be insensitive to the possibility of an ordered progression of changes taking place in what is termed the process of aging. Once again, this is not to lShock, Trends in Gerontology, p. 99. 2Newby, Audiology, p. 49. 3Fowler, "Presbycusis," p. 765. “Birren, Handbook of Aging, p. 6. 18 say that aging and chronological age are identical but only to say that they are related. Presbycusis.--Schaie, Baites, and Strother1 state that the term presbycusis originally was used to describe defective hearing in old people. Glorig and Nixon indicate that in the strictest sense of the word, "presbycusis refers to changes in cell structure that are primarily a degenerative process that is physiological."2 As a further 3 promote the use point of clarification, Glorig and Nixon of three terms to relate hearing loss and the process of aging. They are as follows: (1) presbycusis, which is used to denote physiological changes in the auditory mechanism as a result of aging; (2) sociocusis, descrip- tive of changes in the auditory mechanism resulting from "wear and tear" and not due to any particular occupation; and (3) hearing loss induced by the individual's occupation. Glorig and Nixon state that the first two are related directly to age. Fowler feels that presbycusis refers to a "diminishing hearing acuity incident to advancing years because of a A 1K. Warner Schaie, Paul Baites, and Charles Strother, ”A Study of Auditory Sensitivity in Advanced Age," Journal of Gerontology, XIX (October, 1964), p. 453. 2Aram Glorig and James Nixon, "Hearing Loss as a Function of Age," Laryngoscgpe, LXXII (November, 1962), p. 1596. 31bid., p. 1597. l9 progressive loss of function, mainly in the neural appar- "1 atus of hearing. Schuknecht2 elaborates on the terms epithelial atrophy and neural atrophy, referring to his concept of two types of presbycusis. He states that epithelial atrophy refers to the otological degeneration which begins at the basal end of the cochlea and proceeds towards the apex and which affects all of the structures within equally including the afferent and efferent nerve fibers. He suggests that epithelial atrophy is the otological manifestation of the process of aging which is evident in all body tissue, beginning at middle age and progressing slowly thereafter. Schuknecht states that the neural atrophy "is characterized by degeneration of spiral ganglion cells beginning at the basal end of the cochlea as well as neurons of the higher auditory pathways and is superimposed upon varying degrees of epithelial atrophy."3 He points out also that its onset is late in life and that it progresses very slowly and finally that it is the ". . . otological manifestation of an aging process affecting the central nervous system which is characterized by a loss of neuron population. . . ."4 lFowler, "Presbycusis," p. 764. 2Harold F. Schuknecht, "Presbycusis,” Laryngoscope, LVX (June, 1955), p. 417. 31bid., p. 417. “Ibid., p. 417. 20 Bordleyl classifies hearing impairments of the elderly as (l) conductive, (2) receptive, and (3) perceptive. Receptive impairments in Bordley's classification are a result of lesions in the cochlear part of the peripheral endorgan of hearing and may be associated with partial or complete atrophy of the organ of Corti at the basal turn. In addition, he states there may be an impairment caused by partial atrophy of the cochlear nerve which may or may not be associated with atrophy of the organ of Corti. He describes a perceptive impairment as that caused by degenerative changes in the higher auditory centers of the central nervous system. Weston2 states that presbycusis may often be associated with arteriosclerosis, hypertension, acoustic trauma, or any number of other conditions. In a study of a hospi- 3 found that 16 percent talized geriatric population, Oyer had a loss of auditory function. Among these patients, 44 percent had suffered a cerebral vascular accident, 11 percent had arteriosclerosis, 8.8 percent had arthritis, and an additional 5.8 percent suffered from hypertension. 1John E. Bordley, "The Problems of Geriatric Otology," Transactions American Academy of Ophthalmology and Oto- laryngology,7LXI (March-ApriI, 1957), p. 172. 2T. E. weston, "Deafness," Proceedings of the Royal Society of Medicine, LVIII (August, I965), p. 639. 3Oyer, Auditory Communication, p. 131. 21 In a final remark, Weston concludes that presbycusis "is not a condition in its own right at all, but simply the inevitable result of the operation of one or more processes which are capable of upsetting the organ of hearing and which are particularly liable to occur in old age."1 Pure-tone test results.--There are a number of audio- metric clues which are indicative of a hearing loss resulting from the process of aging, some of which are noted in the pure-tone configuration. Older people evidence a tendency toward a decrease in sensitivity for high frequency tones. The low frequencies are much less affected and only then in the oldest of patients. Generally, one of the first symptoms is a loss of acuity for all tones but the high frequency tones in particular. Stevens and Davis2 state that the frequencies most affected are those above 1000Hz. Fabricant3 estimates that the loss of hearing for high frequency tones occurs at a rate of one lWeston, "Deafness," p. 639. 28. S. Stevens and Hallowell Davis, Hearing (New York: John Wiley and Sons, Inc., 1938), p. 67. 3Noah D. Fabricant, "Deafness in Older Persons," Eye, Ear, Nose and Throat Monthly, XXXIV (January, 1955), p. 56.‘ . 22 decibel per year of life, and Alexander1 states that this loss averages out to be approximately 40dB. Bunch2 studied 353 hospitalized patients who were placed in age groups by decades and found a significant decrease in hearing sensitivity with respect to age. He reported also that those who were grouped in the fourth decade could hear 2048Hz as well as those in the third decade, but each successively older group showed increasing difficulty for this tone. This too held true for tones of a higher frequency where each successive group showed a lessening of sensitivity. Leisti3 tested 451 subjects ranging in age from 16 to 92 years, all subjects reportedly having normal ears. He found that presbycusis may begin between 20 and 30 years of age and that in these earlier years the loss is more pronounced in men than in women. Therefore, by the time an individual reaches the age of 60 and over, the pattern produced by his hearing loss on an audiogram could be best lLucian W. Alexander, "Diagnostic and Etiologic Considerations in Deafness in Older Persons," Journal of the American Geriatrics Society, 11 (June, 19547, p. 389. 2C. C. Bunch, "Age Variations in Auditory Acuity," Archives of Otolaryngology, IX (June, 1929), p. 636. 3T. J. Leisti, "Audiometric Studies of Presbycusis," Acta Oto-Laryngologica, XXXVII (December, 1949), p. 562. 23 described as sloping. Melrose, welsh, and Lutermanl studied 62 elderly men between the ages of 74 and 89 years and con- cluded that there is very little loss in pure-tone sensi- tivity in the 9th decade of life. This tends to be in substantial agreement with Sataloff and Menduke2 who found a low correlation between hearing loss for pure-tones and age after age sixty-five. The subjects in this study were 94 men and 101 women between the ages of 64 and 93 years who had not been exposed to prolonged or intense noise. Klotz and Kilbane3 report that after the age of 60, men have a greater loss than women for frequencies above 1000Hz, and the same holds true in the lower frequencies after the age of 80. In addition, they feel that women may have useful hearing for the higher frequencies until the age of 70. a Corso conducted an exhaustive study in order to evaluate the effects of age and sex on pure-tone thresholds. 1Jay Melrose, Oliver L. welsh, and David M. Luterman, "Auditory Responses in Selected Elderly Men," Journal of Gerontology, XVIII (June, 1963), p. 269. 2Joseph Sataloff and H. Menduke, "Presbycusis," A.M.A. Archives of Otolaryngology, LXVI (September, 1957), p. 274. 3Robert E. Klotz and Marjorie Kilbane, "Hearing in an Aging Population," New England Journal of Medicine, CCXXVI (February, 1962), p. 280. 4John F. Corso, "Aging and Auditory Thresholds in Men and Women," Archives of Environmental Health, VI (March, 1963), p. 356. 24 He selected his subjects from a population that had not been exposed to any significant level of environmental or industrial noise. He concluded the following: 1. Hearing acuity diminishes with advancing age. 2. The effects of aging depend upon frequency with the greatest losses occurring in the 4000Hz to 6000Hz region. 3. In general, age held constant, men have poorer hearing and greater variability in hearing than women except below 1000Hz in the older age groups. 4. The onset of noticeable presbycusis in men occurs at about 32 years of age and proceeds in discreet steps of approximately 15 years, whereas that in women occurs at about 37 years and proceeds at a fairly uniform rate, there- after. Another characteristic of presbycusis is that hearing acuity diminishes equally in both ears. Klotz and Kilbane1 compared the thresholds between better and worse ears in a study of 170 presbycusic subjects and found that the difference rarely exceeds 10dB. They also noted that women were more likely to have the same acuity in both ears; only 12 percent of them averaged a difference greater than 5dB, whereas this discrepancy was noted in half of the men. Discrimination test results.--Carhart2 mentions that the measurement of hearing for speech is essential to lKlotz and Kilbane, "Hearing," p. 279. 2Raymond Carhart, "Basic Principles of Speech Audiometry," Acta Oto-Laryngologica, XL (February, 1951), p. 62. 25 adequate assessment of the complex hearing behavior and needs of patients with auditory impairments. Hirsh feels that much can be gained by having a knowledge of an indivi- dual's sensitivity to pure-tones of different frequencies but that such measurement is too limited to describe the same individual's ability to understand the speech of his fellow communicators."l Carhart states that speech audiometry may be defined as the ”technique wherein stan- dardized samples of a language are presented through a cali- brated system to measure some aspect of hearing ability."2 A speech reception threshold (SRT) and a speech discrimi- nation score may be obtained. Thus, both major aspects of hearing for speech, speech threshold and speech discrimination or intelligibility, can readily be evaluated. Miller indicates that the essential difference between the two aspects of hearing ability is that "intelligibility involves a complex discrimination and identification, whereas audibility is simply a discrimination of presence or absence."3 In speech discrimination testing, Carhart“ reports that the examiner seeks an index of the patient's 1Ira J. Hirsh, The Measurement of Hearing (New York: McGraw-Hill Book 00., I952), p. 1T9. 2Carhart, "Basic Principles," p. 63. 3G. A. Miller, Language and Communication (New York: McGraw-Hill Book Co., 1951), p. 331. “Carhart, "Basic Principlesfi'p. 63. 26 ability to enter successfully into interpersonal verbal communication situations by determining the greatest percentage which a person can receive correctly when speech is made loud enough. 1 state that in aged patients Kirikae, Sate, and Shitara there is an elevation of high frequency thresholds, a lowering of speech discrimination abilities, and a dimin- ished binaural hearing synthesis. Sataloff2 relates that the chief complaint is more often the gradual inability to understand speech and not the most obvious problem of a reduction in sensitivity. 3 suggests that these patients suffering from a Bordley perceptive impairment have a great deal of difficulty in the rapid analysis of complex sound sequences. These are the individuals who hear but have difficulty understanding speech. In addition, Bordley mentions that there is a greater than normal spread between the sound level at which an individual hears a word and that level at which he under- stands it. lKirikae, Sate, and Shitara, "Study of Hearing," p. 219. 2Joseph Sataloff, Hearing Loss (Philadelphia: J. B. Lippincott Co., 1966), p. 127. 3Bordley, "Geriatric Otology," p. 177. 27 Pestalozza and Shorel studied the hearing function of individuals between 60 and 90 years of age. They found that discrimination for speech was very poor, even when there was only a mild loss for pure-tones. In a comparison they found that discrimination for speech in young people was always 9 to 20 percent better than the older indivi- duals who had the same degree of loss for pure-tones. Gaeth2 termed this phenomenon "phonemic regression," stating that it appeared as a frequent accompaniment of presbycusic hearing loss. Pestalozza and Shore described phonemic regression as a "reduction in the abilityto hear and repeat common words at all suprathreshold levels."3 Miller and Ortu tested the hearing of elderly, institutionalized subjects and concluded that there was a severe discrimination loss in the presence of a relatively mild loss for pure-tones. Melrose, welsh, and Luterman5 lG. Pestalozza and 1. Shore, "Clinical Evaluation of Presbycusis on the Basis of Different Tests of Auditory Function," Laryngoscope, LXV (December, 1965), p. 1162. 2John D. Gaeth, "A Study of Phonemic Regression in Relation to Hearing Loss” (Unpublished Ph.D. dissertation, Department of Speech, Northwestern University, 1948). 3Pestalozza and Shore, ”Clinical Evaluation," p. 1161. l+Maurice H. Miller and Ruth G. Ort, "Hearing Problems in a Home for the Aged," Acta Oto-Laryngologica, LIX (January, 1965), p. 40. 5Melrose, welsh, and Luterman, "Auditory Responses," p. 270. 28 in part disagree with this conclusion. They found in their study of 62 elderly men that while discrimination scores were less than expected on the basis of pure-tone results, there were large individual differences. They concluded on the basis of this finding that phonemic regression is not always found in subjects with a presbycusic loss. Pestalozza and Shore,l however, did find that in old indi- viduals there was a clear relationship between hearing loss and discrimination loss. They stated that discrimination worsens as the hearing loss increases. There are, of course, other factors which may have a bearing upon the validity of the obtained scores. Alexander2 points out that lack of attention and slowness of cerebra- tion may have an effect on the test results. weinberg3 suggests that the elderly individual has a lowered psychic energy supply; and since he is unable to cope with all of the incoming stimuli, he naturally begins to exclude them. Speech: A Function of Hearing and Discrimination Over the years there have been numerous authors who have sought through one means or another to draw a clear and lPestalozza and Shore, "Clinical Evaluation," p. 1162. 2Alexander, "Diagnostic Considerations," p. 387. 3Jack weinberg, "Mental Health and Common Emotional Problems of the Elderly," Medical Problems of the Elderly (Univeristy of Texas Postgraduate School of Medicine and the Department of Health, Education, and welfare, Office of Vocational Rehabilitation, 1958), p. 232. 29 concise relationship between the sense of hearing and the ability to speak intelligibly. Unfortunately, save for a few, most of the studies were of an unscientific nature. As a result, there has been little in the way of innovation regarding the field of aural rehabilitation. Audiologists have recently begun to take note of the rehabilitative needs of the hearing impaired adult; and as a result, research and clinical specialists have developed in this most needed area. In the years to come this significant change in clinical and research interest should prove highly beneficial to those in need of aural rehabili- tative measures. Hearing loss and articulatory precision related.--It has been known for many years that the ear acts as a monitor or feedback mechanism with regard to verbal output and precision in the articulatory skills needed for intelli- gible speech. Carhartl states that the ear serves to control the speech mechanism and that speech often degen- erates with an age-associated hearing loss. Newby2 adds that severe or profound loss of hearing results in speech deterioration because the ear is essential for auditory monitoring in the process of articulatory adjustment. Even lRaymond Carhart, "Conservation of Speech," in Hearing and Deafness, ed. by Hallowell Davis (New York: Murray Hill Books, Inc., 1947), p. 301. 2Newby, Audiology, p. 244. 30 a partial loss of hearing occurring in the higher pitch 1 a marked effect upon ranges has, according to Voorhees, articulation. Canfield,2 in discussing the importance of the relationship between defective hearing and speech production, stated that the armed forces had decided to incorporate speech correction in all of their aural rehabilitation programs. 3 describe some of the phonetic west, Kennedy, and Carr characteristics of the acoustically handicapped as follows: (1) inability to form consonants accurately, (2) omission of individual consonants, (3) omission or weakening of final consonants, (4) substitution of a consonant having some perceptible element similar to the correct one, and (5) confusion in the matter of voicing sounds. These Li more articulatory aberrations are, according to Oyer, prevalent in individuals with a perceptive rather than conductive loss. HellerS reports that the sibilant 1Irving W. Voorhees, "Defects in Speech in Relation to Defects in Hearing," Archives of Otolaryngology, XXXI (January, 1940), p. 11. 2Norton Canfield, "Rehabilitation of the Deafened," Journal of Laryngology and Otology, LXII (April, 1948), p. 252. 3Robert west, Lou Kennedy, and Anna Carr, The Rehabilitation of Speech (2d ed.: New York: Harper and Bros., Publishers, I947), p. 351. “Oyer, Auditory Communication, p. 65. 5Morris F. Heller, Functional Otology (New York: Springer Publishing Co., Inc., 1955), p. 198. 31 consonants are either substituted, distorted, or omitted in the speech typical of those suffering from perceptive deafness. O'Neilll feels that the degree of articulatory in- volvement is dependent upon the following: (1) extent of the loss, (2) the age of the patient, and (3) the length of time the patient has had the loss. He states that if the loss has existed for a long period of time and the individual has not used amplification, he will begin to omit final sounds and distort others. west concludes this line of thinking by suggesting that "there is a correlation between defective hearing and defective speech, but not between superior hearing and superior speech."2 Silverman3 feels that the hearing handicapped indivi- dual fails to hear speech patterns clearly and therefore has an inadequate model for imitative purposes. Much of the trouble is because of the type and configuration of the loss. 1John J. O'Neill, The Hard of Hearing (Englewood Cliffs, New Jersey: Prentice-HaIl, Inc., 1964), p. 111. 2west, "Speech and Hearing," p. 575. 38. Richard Silverman, "Clinical and Educational Procedures for the Hard of Hearing," in Handbook of Speech Patholo , ed. by Lee Edward Travis (New York: Appleton- Century-Crofts, Inc., 1957), p. 432. 32 Kelly1 reports that presbycusis for the high frequen- cies progresses with increasing age. As a result, he concludes in part that an individual past 60 is inferior to one with normal hearing at all intensities in consonant recognition. Miller2 indicates that the loss in the clarity of articulation usually follows alterations in vocal quality and intensity. He relates also that the acoustically weak phonetic elements which require a precise articulatory ad- justment are those which are first affected, e.g.[s], [z], 3 reasons, then, that if a sound [tfl , and [d] . Rosenberg is not heard it cannot be reproduced accurately. Continuing with this line of reasoning, Oyer and Doudnah studied hard-of-hearing adults diagnosed as having ”conductive" or "other than conductive" hearing losses and found that auditory discrimination differs as a function of the type of hearing loss. They discovered sound error discrimination differences between the two hearing loss lNoble H. Kelly, "A Study in Presbycusis," Archives of Otolaryngology, XXIX (March, 1939), p. 511. 2Maurice H. Miller, "Speech and Voice Patterns Associated with Hearing Impairment," Maico Audiological Series, II (1964). 3Rosenberg, "Auditory Rehabilitation,” p. 27. “Herbert J. Oyer and Mark Doudna, "Structural Analysis of word Responses Made by Hard of Hearing Subjects on a Discrimination Test," A.M.A. Archives of Otolaryngology, LXX (September, 1959), pp. 363-364. 33 groups and indicated the need for future research on the phonetic characteristics of the speech of these hard-of- hearing individuals. I O'Neilll suggests that when the pure-tone average in the better ear for 500Hz and 2000Hz is from 60-75dB, discrimination scores will range from 30 to 70 percent. He feels that an individual with such a score will have obvious sound distortions but fairly intelligible speech. Penn2 completed a comprehensive report dealing with the speech and vocal characteristics of conductive and perceptive hearing loss populations. In the study he found that among other deviations, those individuals with perceptive losses had a variety of distortions in the articulation of the following: [r], [e], [6], [s], [1], [t3], [d3], and [3]. In a classic study, French and Steinberg,3 using low- pass filtering techniques, found that when all frequencies below 3000Hz were passed, 88 percent of nonsense syllables were heard correctly. When all frequencies below 1000Hz were passed, only 27 percent scores were achieved, thus lO'Neill, Hard of Hearing, p. 75. 2Jacques P. Penn, "Voice and Speech Patterns of the Hard of Hearing," Acta Oto-Laryngologica, Supplement 124 (1955), p. 58. 3N. R. French and J. S. Steinberg, "Factors Governing the Intelligibility of Speech Sounds," Journal of the Acoustical Society of America, XXIX (January, 1947), p. 94. 34 indicating the importance of the frequency component in the 1 added that an appreciable loss discrimination task. Heller of hearing in the 3200-8000Hz range would impair the percep- tion of high frequency sounds and would block their accurate reproduction. Kelly2 studied the effects of high-tone deafness in older subjects on the perception of consonants and vowels. He found that at all intensity levels studied, the subjects with high-tone hearing losses were significantly worse than normals in consonant recognition. Vowel recognition in these subjects did not become impaired until testing was done at lOdB above average normal hearing threshold, at which point they were able to identify only 50 percent of the vowels correctly answered by the normals. It would seem that the aforementioned information would tend to make suspect the ability of an individual to articulate a sound or sounds which he apparently does not hear or perceive. Discrimination and defects in articulation.--There have been research studies in the past which have attempted to relate problems in auditory discrimination to articulatory errors in the speech of children and young adults. There have been few attempts to accomplish the same end with lHeller, Functional Otology, p. 197. 2Kelly, "A Study in Presbycusis,“ p. 512. 35 adults suffering from an acquired, long-standing loss of hearing and ability to discriminate. As a result of the paucity of research pertaining to adults on this topic, several studies pertaining to discrimination and articu- latory defects are presented to indicate the trend in research findings on children and young adults. None of the subjects in these studies to follow have a loss in hearing sensitivity. In 1931 Travis and Rasmusl developed a speech sound discrimination test which presently bears their name. It is composed of 366 pairs of consonant and 66 pairs of vowel combinations. They administered the test to students ranging from first grade through graduate school. Of these subjects, 383 had normal articulation and 165 were judged as being speech defective. They found at every age level that those who were defective in articulation made a signi- ficantly greater number of errors on the test than did the normals. They also analyzed the speech of the most defec- tive group and found that a significant number of the sounds missed on the discrimination test were the same sounds with which the subjects were experiencing the greatest difficulty. in articulation. According to this study, a clear lLee Edward Travis and Bessie Rasmus, "The Speech Sound Discrimination Ability," p. 217. 36 relationship was found between poor discrimination and articulatory imprecision as it pertained to particular sounds. Halll ran a similar study also utilizing the Travis- Rasmus Test in an attempt to investigate the possible rela- tionship between functional articulatory cases and normal speakers, and the results differed from the findings of Travis and Rasmus. Matching groups of university freshmen and elementary grade students to groups of controls, she found no significant differences between the experimental and control groups in their ability to discriminate between pairs of speech sounds. Even in more difficult discrimina- tion tasks involving complex auditory patterns, she found no significant differences between speech defectives in the experimental group and normal speakers in the control group. She concluded that ". . . functional articulatory speech defectives as a group appear to possess no auditory defi- ciencies to account for their speech handicap."2 Mase3 investigated 5th and 6th grade male students who possessed articulatory defects and matched them to those 1Margaret E. Hall, "Auditory Factors in Functional Articulatory Speech Defects," Journal of Experimental Education, VII (December, 19387: p. 122. 21bid., p. 122. 3Darrel J. Mase, ”Etiology of Articulatory Speech Defects," Teachers College Contributions to Education, No. 921 (New York:7Teachers CoIIege, Columbia UniverSlty, 1946), PP. 45-56. 37 with normal speech. He found that while the speech defec- tive group had shown poor auditory discrimination in many instances, the normal group had approximately the same number of children also demonstrating poor ability to discriminate. He summarized by stating that there was no difference in auditory discrimination ability between the speech defective group and a comparable group of normal speakers. Hansenl developed a vowel discrimination test and administered it along with several other tests to three groups of college students. The first group was composed of normal speakers, the second group was speech defective, and the third group was speech defective but had undergone a period of speech correction. He found no significant differences in ability to discriminate among the three groups. Kronvall and Diehl2 studied 30 elementary school children who were found to have severe functional articu- latory defects. These subjects were matched on age, sex, grade, and intelligence to 30 normal speaking children. lBurrell F. Hansen, "The Application of Sound Discrimi- nation Tests to Functional Articulatory Defectives with Normal Hearing," Journal of Speech Disorders, IX (December, 1944), p. 354. 2Ernest L. Kronvall and Charles F. Diehl, "The Rela- tionship of Auditory Discrimination to Articulatory Defects of Children with No Known Organic Impairment," Journal of Speech and Hearing Disorders, XIX (September, 1954), p. 337. 38 The Templin Speech Sound Discrimination Testl was adminis- tered individually to each subject, and on the basis of the obtained results the authors concluded that there is a significant difference in discrimination ability between functional articulatory defectives and normal speakers. They stated that auditory discrimination is responsible for at least some functional articulatory disorders. Sherman and Geith2 administered the Templin Speech Sound Discrimination Test to 529 kindergarten children, and chose 18 children from this group who had achieved high discrimination scores and 18 who had achieved poor dis- crimination scores. Unlike previous studies, these authors did not first separate normal speakers from those with articulatory defects. The articulation of these children was then tested, and as a result of the investigation, they found that ”children of kindergarten age who differ on the Templin Speech Sound Discrimination Test also differ in articulation ability when etiological factors other than speech sound discrimination are ruled out."3 The authors stated that it is reasonable to assume from the results of 1Mildred Templin, "A Study of Sound Discrimination Ability of Elementary School Pupils," Journal of Speech Disorders, VIII (June, 1943), pp. 127-132. 2Dorothy Sherman and Annette Geith, "Speech Sound Discrimination and Articulation Skill," Journal of Speech and Hearing Research, X (June, 1967), p. 278. 31bid., p. 279. 39 the investigation that low speech discrimination is in general causally related to articulatory defects. Schiefelbusch and Lindsey1 pointed out that while the research on phonetic discrimination has not conclusively proven the relationship between poor auditory discrimination and articulatory defects, there is a prevalent opinion that articulation cases are in need of drill in auditory percep- tion before correct speech patterns can be learned. Indeed, Van Riper and Irwin suggest that "in articulation therapy we attempt to heighten the acoustic feedback as a stimulus."2 Spriestersbach and Curtis reported upon this apparent lack of conclusive evidence linking defective articulation with a generalized inability to discriminate speech sounds. They stated that ". . . the assumption is nevertheless logical that certain individuals who misarticulate a given sound may not have developed fully effective awareness of that particular phonetic entity."3 1Richard L. Schiefelbusch and Mary J. Lindsey, "A New Test of Sound Discrimination," Journal of Speech and Hearing Disorders, XXIII (May, 1958), p. 153. 2Van Riper and Irwin, Voice and Articulation, p. 124. 3Duane C. Spriestersbach and James F. Curtis, "Misarticulation and Discrimination of Speech Sounds," Quarterly Journal of Speech, XXXVII (December, 1951), p. 486. 40 Aural Rehabilitation and the Aged Patient The process of aging and its concomitant sensory deprivation was an earlier topic of this report. Aside from the physical manifestations of growing old, there are other problems which are equal in scope and importance to the aging individual. These additional factors often have a great bearing upon the success or failure of the rehabil- itative techniques should they be required. Modern medical advances have resulted in a prolongation of life which is unparalled in the history of man. Gaitz and warshawl state that by 1975 there will be 21 million Americans over the age of 65. Significant numbers of these individuals will be in need of rehabilitative measures of one type or another. Referring specifically to auditory deficiencies, Alpiner reveals that ”in the age range from 25-44, the incidence of hearing impairment is 20.6 per 1,000 persons; in the 45-64 age group, it is 52.2 per 1,000; in 65-74 age group, it rises sharply to 129.2 per 1,000; and in the 75 and over age group, it is 256.4 per 1,000 persons."2 It may be readily seen from the statistics that the bulk of the hearing impaired population rests in the elderly segment of the society. 1Charles M. Gaitz and H. E. Warshaw, "Obstacles Encountered in Correcting Hearing Loss in the Elderly," Geriatrics, XIX (January, 1964), p. 83. 2Jerome G. Alpiner, "Audiologic Problems of the Aged," Geriatrics, XVIII (January, 1963), p. 19. 41 Psychological considerations.--According to Burgessl the desires of the older generation do not differ any from other segments of the population. He feels that older people want to share in much of the following: (1) to engage in meaningful activities, (2) to enjoy the feeling of security, (3) to take part in the give-and-take of affection and sociability, and (4) to have the feeling of identification and participation with others in a common organized activity. A common denominator of these wants and desires is obviously the ability to communicate. Paula and Hardy suggest that a ”hearing disability is essentially a communicative disorder that may affect the very core of the individual's behavior."2 Certainly, an inability to communicate would have devastating psycho- logical consequences to the elderly person who daily experiences growing feelings of insecurity. Gerard sums up these sentiments in an excellent manner by stating that "to maintain life without health is tragic; to maintain 1E. w. Burgess, "Human Aspects of Social Policy," Old Age in the Modern World, Report of the Third Congress of the InternationaI Association of Gerontology (London: E. and S. Livingstone Ltd., 1955), p. 51. 2Miriam D. Paula and William G. Hardy, "Fundamentals in the Treatment of Communicative Disorders Caused by Hearing Disability," Part 1, Journal of Speech and Hearing Disorders, XIII (March, 1948), p. 39. 42 life and health at the animal level without the capacity for interpersonal human behavior is only less so."1 The process of aural rehabilitation.--Hunt feels that "rehabilitation is the process of returning an individual to himself."2 He mentions that progressive hearing loss undermines an individual's self-confidence, attacks his dignity, and endangers his security. He states also that aural rehabilitation is concerned largely with intangibles since it must assuredly involve the restoration of indivi- dual dignity and self-confidence. Heller3 suggests that the goals of aural rehabilitation are as follows: (1) to correct the motor and sensory communicative modalities, (2) to develop and utilize auditory, visual, and kinesthetic clues to attain maximum function, and (3) to teach the patient to learn to live with his handicap and overcome the effects of his disability. In speaking of aural rehabilitation for elderly patients, Alpiner“ tells us that the long-range objective is the improvement of communication function in everyday 1R. w. Gerard, "Aging and Organization," in Handbook of Aging and the Individual, ed. by James E. Birren (Chicago: University of Chicago Press, 1959), p. 273. 2westley'M. Hunt, "Symposium: Progressive Deafness," Laryngoscope, LIV (May, 1944), p. 229. 3Heller, Functional Otology, p. 201. 4Alpiner, "Audiologic Problems," pp. 24-26. 43 activities. weston points out, however, that several factors impede the implementation of a rehabilitation pro- gram, the foremost being the "1argely unconscious deter- mination of old people not to recognize their increasing limitations . . . ."1 He noted in examining the records of his hearing-aid clinic that very few elderly people attended voluntarily and most had to be encouraged by their respective families. Paula and Hardy indicate that "a handicapping hearing loss is the amount of hearing disability which is subjec- tively bothersome to the individual whether or not he admits it."2 There is in addition to this the problem of the individual who has a considerable hearing loss; but because he has unconsciously adjusted to it, he is not cognizant 3 explains that the loss may be of its existence. weston quite imperceptible to the individual because of its gradual onset and progression. weinberg“ indicates that the aging process reduces an individual's ability to deal with multiple stimuli and that as a result many are excluded from awareness. As a result there has been a general disregard noted in the aged lweston, "Deafness," p. 637. 2Paula and Hardy, "Fundamentals," p. 37. 3weston, "Deafness," p. 637. “Weinberg, ”Mental Health,” p. 232. 44 l feels population manifest in a lack of motivation. Oyer that in dealing with the multiply handicapped elderly individual, the presence of motivation is of prime concern. Kaplan sums this up by stating that "if motivation is high, patients with a seemingly insurmountable disability have been able to become self-sufficient; but where the will is lacking, those with apparently minor disabilities have been seriously handicapped."2 Summary This review of the literature has indicated the trend relative to research interest dealing with the relationship between discrimination and the articulate production of speech. The process of aging was investigated initially, and it was found that a fairly predictable decrement in hearing accompanies an increase in longevity. This is to say that as a person grows older, he experiences a gradual lessening in his ability to respond to auditory stimuli. The research data also pointed out that many indivi- duals experience no apparently significant 1033 in hearing sensitivity as a function of aging but do have marked lOyer, Auditory Communication, p. 132. 2Jerome Kaplan, "Community Relationships with the Home for the Aged," Social welfare of the Aging, ed. by Jerome Kaplan and Gordon J. Aldridge (New York: Columbia University ' Press, 1962), p. 14. 45 difficulty analyzing the rapidly uttered phonetic compon- ents of speech. Some studies were presented dealing with the effect of a presbycusic hearing loss on speech produc- tion, but little research evidence was available pertaining to poor discrimination and articulate or intelligible speech production in an adult population. There is an apparent void in our information as to what happens to articulation as an individual acquires a hearing or discrimination loss as a result of the process of aging. There have been studies in the past which have attempted to categorize errors of discrimination as a func- tion of the type of hearing loss, but researchers have yet to begin to relate these errors of discrimination to actual speech production. It would seem that if an individual failed to discriminate a sound or sounds because of a long- standing hearing or discrimination loss, this same indivi- dual would have great difficulty producing these sounds. As a result of the paucity of research dealing with adults on the topic of discrimination and speech production, several studies were presented that dealt with children and young adults on this same question. While the results of these studies appeared to be equivocal, there was a basis for stating that a relationship does exist between poor discrimination for a particular sound or sounds and their faulty production. 46 Lastly, since this study deals with an aged popula- tion, some of the goals and problems of the aural rehabilitation process for the elderly are presented. CHAPTER III PROCEDURES The purpose of this chapter is to describe in detail the subjects, equipment, materials, and procedures necessary for the completion of the proposed investigation. Selection and Grouping of Subjects This section deals with the means by which subjects were selected for participation in the present study. It also indicates how these subjects were subsequently grouped so as to conform to the proposed design of the study. The subjects were obtained from the following diagnostic centers and senior citizens groups in the greater Lansing area: Department of Audiology and Speech Sciences, Michigan State University, East Lansing, Michigan; Rehabilitation Medical Center, Lansing, Michigan; and the Senior Citizens Clubs of East Lansing and Okemos, Michigan. In order to participate in the investigation, a subject could be either a male or female but had to be at least 60 years of age and no older than 75 years of age at the time of testing. Each subject had to be in reasonably good physical health and possess adequate natural or artificial 47 48 dentition to the degree that this could be eliminated as a possible factor in articulatory aberrations. Twenty-four subjects were chosen from an initial pool of eighty names. All of the individuals tested professed to have some degree of difficulty hearing or understanding speech in everyday activities. Eleven males and 13 females were selected and represented a range of ages from 60 to 73 years with a mean age of 66.70 and a median of 65.00 years. The range of ages for the male subjects was 60 to 69 years with a mean age of 64.90 and a median of 65.00 years. The range of ages for the female subjects was 60 to 73 years with a mean age of 68.23 and a median of 65.00 years. The subjects were grouped according to scores which they obtained on a sound field discrimination test. Six subjects were chosen for each of 4 levels which were to represent increased loss in speech discrimination ability. The four levels were made up of those subjects who achieved 90-100%, 80-89%, 70-79%, and 60-69% discrimination scores. The arrangement of these levels and the scores which they represent may be found in Table 1. Individual subjects were tested until all four levels achieved a complement of 6 subjects each. Level 1 was comprised of 4 female and 2 male subjects with a median age of 64.5 years. Level 2 included 2 female and 4 male subjects with a median age of 67.0 years. Level 49 3 had 4 female and 2 male subjects with a median age of 65.5 years. Lastly, Level 4 was comprised of 3 female and 3 male subjects with a median age of 65.0 years. Table l.--Grouping of Subjects as Determined by Discrimi- nation Scores in Percent Achieved on the Northwestern University Auditory Test No. 6. N=24 Level 1 Level 2 Level 3 Level 4 Subject 90-100% 80-89% 70-79% 60-69% 1 90 80 76 68 2 94 82 76 62 3 98 82 78 68 4 94 82 76 64 5 90 88 70 68 6 98 86 74 68 X=94% X=83% X=75% X=66% Auditory testing.--The basis of this investigation rests upon individual sound field discrimination scores, and thus each subject first underwent pure-tone air and bone conduction testing in a sound treated room. Since the test room was not of typical construction, but a thick- walled, acoustically tiled room, an octave band analysis has been provided in Figure l. The ambient noise levels in the room did not exceed the American Standards Associa- tion1 standards for background noise in audiometer test 1American Standard Criteria for Background Noise in Audiometep Test Rooms, American Standards Association (224.3-1951), 10 East 40th Street, New York 16, New York. 50 Fi ure l.--Octave band analysis of sound treated room utllized in sound field testing of speech reception threshold and speech discrimination. UI O .1: U1 4: O U U (A O 25 20 15 10 Sound Pressure Level in dB (re. 0.0002 microbar) b 3 .5 63 12 25o 500 1000 2000 4000 8000 1.000 315000‘ Octave Band Center Frequency in Hertz 51 rooms. The overall noise level in the room was 4ldB as measured on the C scale of a sound level meter. Figures 2, 3, 4, and 5 reflect the mean air conduction thresholds of the four test levels. The mean bone conduc- tion thresholds did not differ significantly from the air conduction thresholds and thus were not plotted on the audiograms. Subsequent to pure-tone examination, each subject was tested for sound field speech reception threshold and sound field discrimination. Taped versions of the w-I spondee word lists were utilized in the determination of speech reception threshold. A taped version of the Northwestern University Auditory Test No. 6 was utilized in the evaluation of discrimination. Form A, lists I, II, III, and IV of these phonetically balanced word lists were used, and they were presented to six individual subjects, each subject receiving one list during the test procedure. The discrimination materials were presented at 40dB SL which according to the research findings of 1 Tillman and Carhart yields a "PB Max“ score. 1Tom w. Tillman and Raymond Carhart, "An Expanded Test for Speech Discrimination Utilizing CNC Monosyllabic Words (United States Air Force School of Aerospace Medicine, SAM-TR-66-55, June, 1966). 52 Figure 2.--Mean air conduction thresholds for subjects achieving discrimination scores between 90 and 100 percent (Level 1). Hearing Threshold Level in dB (ISO 1964) -10. 250 500 1000 2000 4000 8000 K4 —®e 201 30 \\ LA 40 50 60 70 80 90 lOO~ Frequency in Hertz Key to Audiogram Ear Right Left 0- X 53 Figure 3.--Mean air conduction thresholds for subjects achieving discrimination scores between 80 and 89 percent (Level 2). 10 250 500 1000 2000 uooo 8000 0 10 (\Q 20 * 30 \E“ 4O ‘ \ R Hearing Threshold Level in dB (ISO 1964) 50 60 70 §§>_ \L 80 90 1001 Frequency in Hertz Key to Audiogram Ear Right Left 0 X 54 Figure 4.--Mean air conduction thresholds for subjects achieving discrimination scores between 70 and 79 percent (Level 3). 10‘ 250 500 1000 2000 4000 8000 10' 20- 30. 69w \ 50* 60 \f\ 70— O\ 80- <$y__ 90 Hearing Threshold Level in dB (ISO 1964) 100~ Frequency in Hertz Key to Audiogram Ear Right Left 0 X 55 Figure 5.--Mean air conduction thresholds for subjects achieving discrimination scores between 60 and 69 percent (Level 4). 10 250 500 1000 2000 4000 8000 , 0 10 20 89 Z: \\ 2" I\ 7: \4 e .0 ‘45»— 90 Hearing Threshold Level in dB (ISO 1964) 100 Frequency in Hertz Key to Audiogram Ear Right Left 0 X 56 Equipment and Materials The equipment and materials listed below were used in the present investigation and will be referred to through- out this chapter. Equipment Audiometer: Allison, Model 22 Tape Recorder: Ampex, Model Ag-350 Microphone: Electro-Voice, Model 654 Mixer: Ampex, Model MX-35 Power Level Recorder: Bruel and Kjaer, Type 2305 Sound Level Meter and Sound Field Microphone: Bruel and Kjaer, Type 2203 Bruel and Kjaer, Type 4131 Filter: Bruel and Kjaer, Type 1613 Artificial Ear and Pressure Microphone: Bruel and Kjaer, Type 4153 Bruel and Kjaer, Type 4132 57 Testing Booth: Industrial Acoustics Corporation, Series 4001 Acoustically Tiled Test Suite2 Materials. Templin-Darley Test of Articulation3 Multiple-Choice Intelligibility Test, Forms C and D Magnetic Recording Tape (3M, Type 201) Procedures After a subject had been tested and assigned to an experimental group on the basis of his discrimination score, two subsequent tests were administered which were to form the basis of the present study. The presentation of each of these procedures is to follow. Articulation test.--Each subject was obliged to undergo a test of his articulatory precision. As a prelude to this examination, an oral peripheral evaluation was made in order to determine that all structures were intact and functioning adequately for speech. Diadochokinetic rates lUtilized in the recording of Multiple-Choice Intelli- gibility Test lists. 2Utilized in the tests of auditory function and the playback of the Multiple—Choice Intelligibility Test lists. 3Mildred C. Templin and Frederic L. Darley, The Tem lin- Darlgy Tests of Articulation: A Manual and Discussion of tEe Screening and Diagnostic Tests (Iowa City: Bureau of Educa- Iional Research and Service, State University of Iowa, 1960). “John w. Black, Multiple-Choice Intelligibility Test (Danville, Illinois: Interstate Printers and Publishers, Inc., 1963). 58 were checked as was the range of motion of the active articulators. The security of artificial dentition was also examined. This was done in an attempt to eliminate any subject who might have an articulatory defect as a result of some physical manifestation other than that of a long-standing hearing 1088. Selected items from the Templin-Darley Test of Articulationl were chosen for this study. The first 43 items of the test were used, and they appear in Table 2. This initial portion of the test includes the examination of 12 vowels, 6 diphthongs, and 68 consonants appearing in the initial, medial, and final positions where appli- cable. Since neither the complete diagnostic test nor the screening test was used, no attempt was made to relate the findings of the present study to the normative data of this particular test of articulation. Three judges were chosen to assess the articulatory precision of each of the subjects. The judges who were selected for this task each held an advanced degree in Speech Pathology and Audiology. During the testing the three judges sat opposite the subject as he read aloud the items appearing in Table 2. Also, in order to ease the burden of reading on the subjects, the test words were printed with a typewriter equipped with primary type. lTemplin and Darley, Tests of Articulation, p. 22. 59 Table 2.--Selected items from the Templin-Barley Test of Articulation with accompanying phonetic symbols for each test sound. 13. 14, 15. Vowels ,Word Symbol Word feet [1] 7. bird pin 1] 8. car bed is] 9. clock cat [$1 10. ball gun [A] 11. book balloon [a] 12. shoe Diphthongs music [ju] 16. cake cone [on] 17. pie house [an] 18. boy Consonants 26: Words mittens, lemon, drum nose, banana, spoon swinging, ring pencil, sleeping, cup bear, baby, tub tongue, eating, boat doll, wading, slide kiss, pocket, duck girl, wagon, dog rabbit, arrow leaf, umbrella, bell fence, telephone, knife valentine thumb there, feather, smooth soap, bicycle, mouse zipper, scissors, windows sheep, dishes, fish television, garage horse, grasshopper wheel, black and white water, sandwich yellow, onion chair, matches, watch jar, engine, bridge ELM r_"_1f—firfiFfif—‘HfiflHI—‘F‘Hl—‘f—‘HF‘F‘HHHF‘HI—HHH aflbé:menwwm®».0134) as may be observed in Table 9. lBlack, Multiple-Choice Intelligibility Test, pp. 13-22. 77 Since a significant difference was found on the analysis of variance, Mann-Whitney U tests were per- formed in order to make individual comparisons. The results of these comparisons may be found in Table 10. Table 9.--Summary of Kruskal-wallis One-way Analysis of Variance Comparing Four Levels of Discrimination and Speaker Intelligibility. Mean Score Level Rank Sum Sample Size in % 1 107.00 6 73.50 2 96.50 6 66.00 3 59.00 6 53.83 4 37.50 6 43.83 Kruskal-wallis H=10.64 significant at r(I,M) r(I) V(I) 3(1,M,F) z(I,M,F) s(M,F) l