TTTTTTT 51 TTTTTTT TTTTTTT TTT 3}! E813 This is to certify that the thesis entitled THE ABILITY 0F DOWN'S SYNDROME SUBJECTS T0 SYNCHRONIZE RHYTHMIC MOTOR RESPONSE TO THE BEAT OF A MUSICAL STIMULUS presented by Roger Aue Smeltekop, RMT has been accepted towards fulfillment of the requirements for MASTER degree in MUSIC Major professor Dale L. Bartlett Date 3 August 1983 0-7639 MSU is an Affirmative Action/Equal Opportunity Institution _.._.__. --__..._ _.._.._.._ _.______ PLACE IN RETURN BOX to remove this checkout from your record. TO AVOID FINES return on or before date due. MAY BE RECALLED with earlier due date if requested. T BATE DUE DATE DUE DATE DUE 1m; 0 afoot 6/01 c:/CIRC/DaieDue.p65-p.15 . '.._~‘_‘ __’ . THE ABILITY OF DOWN'S SYNDROME SUBJECTS TO SYNCHRONIZE RHYTHMIC MOTOR RESPONSE TO THE BEAT OF A MUSICAL STIMULUS By Roger Aue Smeltekop, RMT A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF MUSIC, MUSIC THERAPY Department of Music T983 I41rquP ABSTRACT THE ABILITY OF DOWN'S SYNDROME SUBJECTS TO SYNCHRONIZE RHYTHMIC MOTOR RESPONSE TO THE BEAT OF A MUSICAL STIMULUS' By Roger Aue Smeltekop The purpose of this study was to examine the Down's Syndrome per- son's ability to synchronize motor responses to an external stimulus and to identify the relationship between synchronization accuracy and stimulus tempo, as well as age and intelligence. Each of twenty-one DS subjects were randomly assigned to one of three experimental tempo conditions: slow, fast, or choice. They were tested in a performance task of playing a drum to a music stimulus. The stimulus and the motor response were recorded on a two-channel chart recorder. Deviations of the response beat length from the stimulus beat length were calculated and the mean differences were compared across experimental conditions and in relation to IQ and age. Small differences in beat length deviation were found across the three group means. The tempo of choice had the least error, followed by the fast and then the slow. Only the difference between the tempo of choice and the slow tempo was found to be statistically significant. 08 subjects showed a slight, but consistent, tendency to respond faster than the beat. No significant relationship was shown between synchronization accuracy and intelligence and age. To my wife, Diane Cratsley, whose personal support and generous assistance were invaluable in the implementation and completion of this study ACKNOWLEDGEMENTS Grateful appreciation is extended to Professor Robert F. Unkefer and Dr. Dale Bartlett for their support, guidance, and expertise contributed toward the accomplishment of this research study. Thanks and acknowledgement are offered for individual help and contributions by Dr. Ron Newman, Diane Cratsley, Michael Thaut, Dr. David Fuller, and June McGregor-Lee. A very special thanks is given to the Down's Syndrome children and adults and their parents for their very essential cooperation and participation in this study. TABLE OF CONTENTS LIST OF TABLES ......................... vi ABBREVIATIONS ......................... vii CHAPTER I. THE PROBLEM ....................... 1 Introduction ...................... 1 Purpose of the Study .................. 1 Need for the Study .................. 3 Research Questions .................. 3 Assumptions ...................... 4 Limitations ...................... 5 Overview ........................ 7 II. REVIEW OF RELATED LITERATURE ............... 8 Overview ........................ 8 Rhythmic Synchronization and Music ........... 8 Development of Rhythmic Skills ........... 9 Measurement of Rhythmic Synchronization ,,,,,,, 12 The Influence of Tempo ............... 16 Other Related Concerns ............... 18 Relationship of Intelligence to Rhythmic Skills , , , 19 Relationship of Rhythmic Skills to Other Areas of Human Behavior ................ 20 Down's Syndrome .................... 22 Identification of the Syndrome ........... 22 Mental Development ................. 23 Physiological Characteristics ............ 25 Personality ..................... 25 Speech and Language ................. 27 Sensorimotor .................... 28 Studies of Rhythm and Motor Skills in US ,,,,,,,, 29 Summary ........................ 33 III. METHODOLOGY ........................ 34 Sample ........................ 34 Design ........................ 35 Setting and Procedure ................. 36 Measurement ...................... 44 iv Special Considerations ............... Pilot Testing .................... Analysis ...................... Summary ....................... IV. RESULTS ........................ Findings ...................... Review of Research Questions ............ Interpretations ................... Summary ....................... V. SUMMARY AND CONCLUSIONS ................ Summary ....................... Conclusions ..................... Discussion ..................... Implications for Future Research .......... APPENDICES A. GLOSSARY OF TERMS ................... 8. RAW DATA AND DEMOGRAPHIC INFORMATION .......... C. RHYTHMIC SYNCHRONIZATION TEST (Procedure) ....... D. MUSIC USED IN TESTING ................. FOOTNOTES ........................... REFERENCES .......................... 61 62 63 67 68 7O LIST OF TABLES Group Means for Deviations of Response Beat Length (RBL) from Stimulus Beat Length (SBL) .............. 46 Analysis of Variance for the Mean Deviation of the Response Beat Lengths (RBL) from the Stimulus Beat Length (SBL) ..................... 47 Tukey Multiple Comparison of Honestly Significant Difference (hsd) ..................... 48 Rank-Order Coefficients Resulting from Correlations of Mean Deviation Scores with IQ and Age ........... 48 vi CA: 05: EMI: EMR: IQ: MA: RBL: SBL: TMI: TMR: ABBREVIATIONS chronological age Down's Syndrome educable mentally impaired educable mentally retarded intelligence quotient mental age response beat length (subject) stimulus beat length (music) trainable mentally impaired trainable mentally retarded vii CHAPTER I THE PROBLEM Introduction The person with Down's Syndrome (US) has long been a prominent member of the mentally impaired population. Considerable time and effort have been devoted by health professionals, families, and commun- ity members to the growth, development, and habilitation of these handicapped individuals. This seems largely due to the demonstrated adaptive ability and temperament characteristics that enhance the potential for 05 people to make satisfactory adjustments to community life. Such adjustment is, in part, dependent upon the degree of development in communication, cognition, and social, emotional, and perceptual-motor functional skill areas, as well as upon the types of support systems present in the individual's environment. These factors combine to determine the level of independence a person can achieve in self-care, education, work, and leisure time activities. Purpose of the Study The purpose of this study was to examine the DS person's ability to synchronize motor responses to an external stimulus. In particular, it was intended to identify the relationship between synchronization accuracy and stimulus tempo, as well as synchronization accuracy and intelligence level. Since this specific skill has direct application 2 in the area of music performance through the action of executing motor responses to the beat of music, this skill was tested in a musical context. A performance task was used rather than a discrimination task, despite the greater difficulty in logistics and instrumentation for testing, because rhythmic synchronization is most practical and relevant to everyday functioning in the performance mode. Most studies have not made a precise measurement of the accuracy of rhythmic synchronization and have not described whether inaccuracies in this skill demonstrate any common characteristics, such as a tendency to lag or fall behind the beat. It has been observed in music therapy clinical settings that, while many DS clients enjoy rhythmic movement activities such as dancing and playing instruments, and perform them with apparent coordination and grace, their responses do not appear to be actually synchronized with the pulse of the musical accompaniment. In certain types of musical pursuits, e.g. informal popular danc- ing, synchronization with the beat is not a requisite for enjoying the activity. In many others, such as ensemble playing or structured folk dance, the relative aesthetic and interpersonal success is highly dependent upon the participant's ability to coordinate the timing of his/her responses to the group's concerted efforts. Just as the ability to synchronize one's movements to an external stimulus can be important to music and other leisure time activities, this ability also has implications regarding a person's potential to successfully perform many types of work related functions (Clark and Hermelin, I955; Fitzpatrick, l959; Rowlson, 1983). The operation of many production-line 3 machines or the perfonnance of an individual repetitive task as part of an assembly line sequence often requires a timely response to a cue from another person or external source. Need for the Study This research is intended to add to the limited amount of litera- ture in the area of rhythmic synchronization in US. The results may also shed light on the precision of 05 responses to music. The effects of different tempi on the DS person's success at coordinating motor responses may be of use to health and education professionals. The way in which tempo influences synchronization may offer a principle through which work and leisure time activities can be accomplished more effectively and efficiently. Specific implications for music therapy are that this study may provide a direction for future research and may identify a role that music therapy can serve in coordination with educational and vocational goals for 05 people. Research Questions 1. To what degree of accuracy can a DS person synchronize motor response to a regularly occurring external auditory stimulus (the beat of music)? 2. Do DS persons demonstrate similar characteristics in motor synchron- ization? 3. Is motor synchronization ability in D8 persons affected by the speed of the stimulus events (the tempo of the music)? 45 0 Is there a significant relationship between motor synchronization ability and measured intelligence (IQ) and age in 08 persons? Assumptions Down's Syndrome persons, as well as others who are mentally impaired (mentally retarded), have been shown to be somewhat difficult to test in situations that are unfamiliar to them and in which they are ill at ease (Cantor and Girardeau, l959; Kaplan, 1977). The procedure designed for the testing session, including a musical warm-up activity, a series of training items, the rhythmic synchroniza- tion test, and a closing musical activity, is believed to facilitate a higher level of responsiveness. Therefore, the performance scores for the DS subjects are expected to more closely reflect their actual abilities, with minimal interference from the novelty of the testing situation. The US person will respond at a closer to optimum skill level when performing to a musical stimulus. The recorded music to be used in this study was composed using harmonies common to popular musical styles, in the belief that music of this type would be familiar and motivating to the subjects. The music was performed on the piano in an effort to give it a percussive and clear quality. Though the US person is believed to be responsive to imitation (Fitzpatrick, 1959), the rhythmic synchronization tasks will be practiced with the experimenter, but the experimenter's modeling will be faded out to avoid the possibility of misleading the subject by any errors in the experimenter's performance during the measurement. This will also provide some assurance that the response is solely to an auditory stimulus, and not confounded by a possible discrepancy and/or conflict between the subject's auditory and visual perception skills. 5 There is some evidence that the level of coordination shown in performance of motor tasks using the arms and hands is not superior to coordination shown in tasks using the feet and legs. If this is the case, the rhythmic synchronization skill levels described by this study should generalize from drum beating activities to activities using the lower extremities using a similar single movement, such as tapping one foot or depressing a pedal. An early study reported a correlation of .80 between clapping and walking skills in normal subjects (Jersild and Bienstock, 1935).1 A later study indicated that rhythmic performance (defined as fine motor movement using hands) and rhythmic movement (defined as gross motor movement as in stepping and total body movement) correlated at .59. However, the measurement of the highly variable gross motor movement was made by "subjective assessments of a panel of judges who agreed upon the nature of the tests to be used and the points on which the subjects were to be assessed,"2 a technique of questionable accuracy (Thackray, T969). Limitations This study looked only at the DS person's skills in rhythmic synchronization as compared to a standard of absolute synchronization, measured accurately to within .Ol second; it did not purport to describe the abilities in this skill area of the normal population. No attempt was made to identify the specific causes or origins of any of the rhythmic characteristics observed, but simply intended to describe them in the DS population in relation to intelligence and tempo chosen. This study did not attempt to compare the subject's performance with relation to sex. 6 While skills in rhythmic synchronization are most likely influenced by skills in general motor performance (Night, l937; Groves, 1969), the latter was not measured. However, any subjects who had specifically diagnosed motor or physical disabilities that might unusually influence the performance of the motor task, such as cerebral palsy or significant sensory impairment, were eliminated from the study. The sample p0pulation was drawn from the Greater Lansing area (Mich- igan), and included only those who volunteered to participate in the study. In addition, the parents or guardians of subjects taking part had to be willing to transport the subject to the testing site on the Michigan State University campus. The degree to which the sample used represented the total US population was also influenced by the limited number of available US subjects. The above factors limited the generalizability of the experimental results and conclusions of the study. Whether the level of skill in rhythmic synchronization possessed by a US person could be improved through training or through altering the conditions, other than tempo, under which such tasks are performed was not within the scope of this investigation. However, the factors cited above could be very important when interpreting and/or applying the conclusions from this study. This is especially pertinent when making decisions regarding types of experiences to be provided in pro- grams for DS persons. It is not suggested that any lack of performance skill in this area is equated to lack of performance potential. Thus, it should not be the basis for restricting the DS person from programs or interventions designed to improve rhythmic synchronization. In like manner, the 7 assumption cannot be made from results obtained in this study that instituting programs for motor performance will bring about an improve- ment in rhythmic synchronization. Overview In Chapter II the background of this study is presented in a literature review. A survey of rhythmic synchronization, particularly as it occurs in music, is made in the first section. The second sec- tion describes current findings on the characteristics of Down's Syndrome. In the last section selected studies of rhythm and motor skills in 03 are reviewed. Chapter III includes the methodology used in studying rhythmic synchronization in US persons. The sample, design, measurement pro- cedures, variables involved, and analysis of data are described. In Chapter IV the data collected are presented in relation to the relevant research questions investigated, and the results are interpreted. Chapter V is a summary of the study with the discussion of conclusions and suggestions for future research. The appendix includes a glossary of terms, a table of the raw data collected, the instructions to subjects in the testing session, and the musical examples used in the testing. CHAPTER II REVIEW OF RELATED LITERATURE Overview The review of related literature is divided into three major sections and a summary: l. Rhythmic Synchronization and Music 2. Down's Syndrome 3. Studies of Rhythm and Motor Skills in D3 4. Summary Each area is further broken down into sub-sections relevant to this study. Rhythmic Synchronization and Music The element of rhythm is a major factor in the successful per- formance of music. Teachers, researchers, and therapists in music have observed and investigated the acquisition of rhythmic skills with special interest in the processes by which they are acquired, the ages at which rhythmic achievements occur, and the influence that various factors, such as training, has on the development of these skills. This study is concerned with just one basic facet of rhythm, that of the syrchronization of motor responses to an externally imposed musical beat in OS individuals. Development of Rhythmic Skills It is from the studies of normal rhythmic skill development that the foundation and perspective are gathered to guide the investigation of rhythmic skills in the handicapped. Past researchers have concluded that rhythmic skills are usually acquired by age eight (Petzold, 1969) to age ten (Hufstader, l977). Synchronization is reported to stabilize at five and one-half years (Williams, 1932) to seven years of age (Petzold, 1969; Cox, 1977). The predominant conclusion by researchers has been that as age increases, failure at rhythmic skills decreases (Vance and Grandprey, 1931; Sievers, 1932; Jersild and Bienstock, 1935; Gilbert, 1979). Many studies of perceptual-motor skills involving subjects of normal and mentally retarded intelligence have matched experimental and control samples by mental age equivalents (Cantor and Girardeau, 1959; O'Connor and Hermelin, 1961; Peters, 1978; Dummer, 1978). However, one study matched samples of DS, autistic, and normals by performance scores in tapping speed and rotary pursuit tracking (Frith and Frith, 1974). The frequent use of mental age equivalents to compare normal subjects to mentally retarded subjects, who are consequently at a considerably higher chronological age, suggests that to look at normal rhythmic development might be of value in predicting the performance of mentally retarded subjects at various mental age levels. Given that the mental ages of the majority of DS individuals fall below four years with the upper limit at seven years (Gibson, 1978), the measured performance levels to be shown by this study may be attributable to the low level of mental development rather than to any 10 unique characteristic of the DS person’s genetic make-up. In other words, the DS subject may not have reached the mental age at which motor synchronization skills are acquired. A number of researchers have shed light on the development of rhythmic skills through the study of Jean Piaget's stages of cognitive development (Pflederer, 1967). Conservation skills are those through which a child recognizes that some properties of an object or event remain constant at the same time that other properties are altered. For example, conservation of volume is exhibited by the acknowledgement that a liquid in a short, wide container remains equal in volume when transferred to a tall, thin container. Zimmerman and Sechrest (1970) concluded that age is a significant factor in the acquisition(Hiconservation skills. In their study, a common melody was played and then repeated, either exactly the same or with the deformation (change) of one musical element. The subjects were asked to identify "same, different, or same and different", and then describe the ways in which they perceived any difference. Subjects were given conservation scores based on their recognition of changes in rhythm and tempo, as well as instrument, harmony, melodic contour, melodic interval, and mode. Included in Jones' (1976) study of the conception of meter in music, was a conservation of velocity task in which the subject watched the passage of two equal time intervals of fifteen seconds on a stopwatch, but with a metronome ticking at a different rate each time. The subject was then asked if the st0pwatch hand went the same speed both times. His results indicated that this skill was achieved by the age of seven years. 11 In a follow-up of Jones' work, Perney (1976) conducted a similar investigation of conservation of metric time in second and third graders. A person who is a conserver with respect to metric time can accurately relate the duration of events and the speed at which the events take place. Before conservation of metric time is acquired, a child's 'internal clock' is not invariant; that is, certain changes in the child's environment can cause the child's 'clock' to vary in speed. While the performance of the second and third graders did not significantly differ, he found support for his hypothesis that perfor- mance on the musical tasks were significantly related to verbal ability, more than age. From the writings of Piaget and others, Bagenstos and LeBlanc (1975) concluded that learning in relation to time was premature before age seven, and therefore did not study it in their "Aesthetics in the Physical World" program (CEMREL, Inc.) for kindergarten and first grade. Cantor and Girardeau (1959) reported that neither a 08 group with a mean mental age of 4-4 (years-months) nor a normal group with a mean mental age of 5-6 successfully tapped synchronously to a metronome. Kaplan (1977) compared subjects who were EMR (higher level than most D5) of six, seven, and eight years of mental age with normal six, seven, and eight year-old children. She found no significant differences between them in response to musical beat, with the exception of echo tapping skills, in which the normals were superior. 12 Measurement of Rhythmic Synchronization Evidence for rhythmic skill has been gathered for research by means of evaluating both performance skills and discrimination skills. A number of researchers have indicated the benefit and need for per- formance studies. Pflederer (1964) in her study of five to eight year-olds' abilities to use Piaget's principle of conservation in musical tasks, noted that the children achieved correct discriminations more readily when they overtly interacted with the task, in such ways as clapping or counting. ”The child seemed to reason with a form of sensori-motor intelligence whereinhis own actions served as a guide for thought by providing a model to guide his judgement in solving the task."4 Among the recommendations made by Kuhn (1974) for future research was that investigations of the recognition of tempo modulation be done as studies of music performance, rather than discrimination. Zimmerman and Schrest (1970) studied the effects of "brief focused instruction" on the acquisition of musical concepts, one of which was tempo, in normal children ages five to thirteen. One of their recommendations was that "some type of musical task be devised in which the critical response is not dependent upon verbal capabilities."5 Andrews and Deihl (1970) stated that overt and manipulative measures would have particular value with handicapped children. Re- garding 03 individuals, Gibson (1978) added: "Maintenance of a single interest is more often evident when motor discharge is continuously engaged, as in dancing or mimicry".6 Research evidence indicates that the relationship between rhythmic perception skills and rhythmic performance skills in normal subjects is 13 positive but not close. Thackray (1969) found a correlation of .63 between these two skill areas.7 Other researchers have also suggested a small relationship between perception and performance skills in normal musically trained subjects (Marciniak, 1974) and very young musically non-trained normal subjects (Andrews and Deihl, 1970). Cantor and Girardeau (1959) found that motor response to a rhythmic stimulus aided neither normals nor 05 subjects to discriminate and identify fast and slow tempi. Various methods of measuring rhythmic performance have been em- ployed to gather data for research. Some researchers have used observational ratings by expert judges, either during testing (Thackray, 1969; Ross, Ross, Kuchenbecker, 1973) or by videotaped replay (Gilbert, 1979). Others have used performance sections of standardized tests. Past studies, however, have indicated that observational measure- ments are inaccurate in comparison to objective measures (Heinlein, 1929; Jersild and Bienstock, 1935). Most of the objective measurements reviewed have recorded responses within tolerances of as low as .05 second up to .10 second (Sievers, 1932; Jersild and Bienstock, 1935; Petzold, 1966; Kaplan, 1977). Smoll (1975) measured temporal accuracy to within .01 second. McDowell (1977) designed a Rhythmic Ability Test of several sec- tions, one of which measured the subject's ability to reproduce a tempo given by a metronome. Each subject was presented with eight beats of an audible tick and a visible flash of light, followed by eight beats of just the flashing light. During the latter eight beats, the subject was to reproduce the tempo by playing on a woodblock. The response was tape recorded, and one point was given if there were eight taps 14 during the eight silent beats. He tested each subject at the following tempi: 60, 66, 72, 80, 88, 96, 104, 112, 120, and 132 beats/minute. He found that the eight-year-olds he tested performed better than four-year-olds, that subjects tended to reproduce the faster tempi better than the slower ones, and that one month of specific rhythm training did not significantly improve the scores of the four-year-olds in his sample. A recent study was conducted by Phyllis Kaplan (1977) using electronic technology to measure rhythmic responses of normal and EMR children. She devised a Test of Rhythmic Responsiveness which contained five subtests of rhythmic skill: 1. Beat 11. Tempo Change: Gradual Tempo Change: Sudden III. Accent (as a factor in meter discrimination) IV. Durational Patterns: Melodic Rhythm Durational Patterns: Echo Tapping V. Ostinato8 Of particular interest was her use of the TAP Master (developed by David L. Shrader and produced by Temporal Acuity Products, Inc.) on subtest I. Beat. The device played music on a cassette tape to which electronic impulses had been added to coincide with the music's beat. When the subject pressed a button within $.10 second of the beat, a digital counter recorded the correct response and an auditory feedback "beep" was given to the subject. Subjects were given practice items and were tested on these items at each of the following tempi: 66, 108, 160 beats/minute. Subjects were observed during the measurement, and no 15 credit was given for double-time tapping. Scores on this subtest were taken from the tally on the digital counter. Kaplan tested twelve subjects in each of six groups: normals grouped by ages six, seven, and eight years, and EMR's grouped by mental age equivalents of six, seven, and eight years. No significant differences were found between the normals and EMR subjects on this test. Kaplan reviewed the technology used by several researchers prior to her study: 1. Baldwin and Stecher (1924) recorded responses through wooden clappers wired to an electronic kymograph. 2. Heinlein (1929) electrically wired the floor to record the subjects' actual steps through kymograph pens (also for each step observers simultaneously tapped telegraph keys attached to the kymograph, to test for accuracy of observational judgements.) 3. William's (1932) subjects tapped a brass plate with a hammer to a ticking clock, recorded by the deflection of a spiral pen attached to a turntable. 4. Jersild and Bienstock (1935) determined synchronization by filming a blinking light stimulus, a one revolution/second clock, and the subject's response simultaneously. They then examined each film frame to determine accuracy within a $.08 tolerance; they counted only responses preceded by a correct response. 5. Petzold (1966) used a two channel polygraph to give a simultaneous record on paper of the stimulus (metronome beats) and the sub- ject's response (tapping on a metal plate); he scored thirty respon- ses beginning with the first one correct within a tolerance of f.06 second.9 16 In an investigation of the ability of trained musicians to accurately perform rhythmic notation, Drake (1968) devised an electronic apparatus to produce a regular, audible, metronomic click and an audible pure tone upon the independent tapping of a key, both of which were electronically recorded on magnetic tape. The subject performed notated rhythms by tapping on the key to the beat of the metronome click, which was silenced after the performance of each item had begun. The data collected on the magnetic tape were transferred to visual form through the use of a Dynograph chart recorder. Of interest to this study was his calculation of error in beat accuracy. Beat reproduc- tion error was measured by the difference between a required beat length and the mean of the observed (subject's) beat lengths for an item. Beat steadiness error was measured by the difference between an observed beat length and the mean of the observed beat lengths of an item. The Influence of Tempo Tempi used by other researchers in studying rhythmic skills are represented by the following ranges: slow - fast (beats/minute) Williams, 1932 60 - 120 Cantor and Girardeau, 1959 88 - 120 Petzold, 1966 60 - 182 Kuhn, 1974 60 - 150 McDowell, 1974 60 - 132 Taebel, 1974 84 - 112 Kaplan, 1977 60 - 160 Dorhout, 1979 60 - 120 17 Petzold reported that at 60 beats/minute, subjects often gave a double-time response. Several researchers concluded that the faster tempi produced greater accuracy than the slower ones (Williams, 1932; Jersild and Bienstock, 1935; Christianson, 1938; Petzold, 1966; McDowell, 1974; Kaplan, 1977). This held true for normal subjects, and in Kaplan's study the EMR subjects showed the same trend. Smoll and Schutz (1978) continued Smoll's earlier work (1975) in the investigation of rhythmic motor performance and the influence of preferred tempo. Their sample consisted of two hundred college undergraduates. They measured both spatial and temporal accuracy in an arm swing motion, moving the extended arm at the shoulder from a vertical to horizontal position and back. While holding a light mechanical arm attached electronically to a digital printer, subjects responded to an audio-visual stimulus (a short tone and a blinking light) at a tempo that each had chosen as comfortable. The researchers found variability of tempo to be less at faster tempi. They also re- lated a very low correlation between preferred tempo and temporal accuracy, measured as the deviation from the stimulus beat. They considered that these two performance attributes were independent of each other, thus the influence of preferred tempo on rhythmic accuracy was unclear and needed further investigation. Kuhn (1974) found that increases in tempo were not as readily dis- criminated as decreases in tempo. Further, a later study revealed that musically trained subjects from first grade to college under- graduates increased performance (clapping) tempi significantly. Their performance was measured during a period that continued for a specific time interval after the 90 beat/minute stimulus ceased (Kuhn and Gates, 1975). Earlier research by Williams (1932) suggested that subjects 18 tended to anticipate the beat rather than delay. In his study of non- major college band musicians Drake (1968) concluded that there was a marked tendency to "shorten beats or play faster than a given, or required beat while performing musical durational notation."10 The findings of Petzold (1966) supports this conclusion. Kaplan (1977) reported, from her review of the pre-recorded materials that accompanied the major elementary music texts, that no particular tempo emerged as one considered by the various authors as most suitable for elementary school learning. However, the range of 77-108 beats/minute, identified as Andante, appeared most frequently. Kuhn (1974) suggested the following from his studies of tempo discrimination: a tempo of 90 should be used for slow examples with subjects of varying ages and musical training (He had used 60 as the slow tempo in testing professional musicians.); examples for inex- perienced subjects should be twenty seconds long; and actual music should be used, rather than non-musical stimuli. Other Related Concerns In the course of their research and writings, some authors have made miscellaneous, but relevant, points about conducting investiga- tions in the area of rhythmic behavior. Rainbow (1977) suggested that the performance of a steady rhythmic beat may be one of the most difficult tasks for children, and even adults, to learn. From this study of normal four-to-five-year old children, he concluded that vocally chanting a rhythm was more easily and accurately completed than stepping or clapping. Bentley (1966)stressed the point that musical tests should give several practice examples so that the task itself is understood; he 19 also suggested that comparing stimulus events of varying lengths can be confusing to a child. In relation to testing handicapped subjects other researchers have suggested that ample and simple example items for performance should be given (McLeish and Higgs, n.d.; Bixler, 1968; Kaplan, 1977), and more than usual encouragement may be necessary (Walton and Begg, 1955; Kaplan, 1977.) Relationship of Intelligence to Rhythmic Skills The question of whether rhythmic skills are closely related to intelligence'hsnot clearly answered by the literature encountered by this researcher. In an early study by Jersild and Bienstock (1935) IQ and rhythmic performance scores, measured in walking and clapping, correlated variably, though most correlations were positive. Wight (1937) also found "Rhythmization", the ability to reproduce rhythm patterns, and IQ both related to motor coordination, measured by tapping speed in handicapped children. A recent look at rhythmic perception by Lienhard (1976), through discrimination of sameness and difference in pairs of rhythms, showed that IQ accounted for the largest portion of variation (13.23%). The subjects were mentally retarded, with an average age of sixteen years and a mean IQ of forty-six. Kaplan's study (1977) may support the view that intelligence influences rhythmic performance, in that her groups matched by mental age, but differing in chronological age, did not show significant differences in most areas. On the other side of the question, Bentley (1966) concluded that there was a low correlation between general musical ability and IQ in 20 normals, and Bixler (1968) stated that he found a low correlation between Gordon's Musical Aptitude Profile and four IQ measures in EMR subjects. Rhythm was correlated to mental age at .17. In early research, Sievers (1932) and Christianson (1938) found IQ to not be significantly related to motor synchronization skills. More recently Langille (1977) studied normal second graders and concluded that IQ did not have a significant effect on rhythmic pattern perception. Relationship of Rhythmic Skills to Other Areas of Human Behavior While research findings seemed sparse in establishing the benefits of musical and rhythmic skills as precipitants to gains in other skill areas, the idea has received some attention and peripheral support from researchers and other experts in the field of development for the handicapped. Langille (1977) reported findings that rhythmic pattern perception and auditory discrimination skills were related to reading vocabulary and comprehension. Wolff (1979) noted that musical instruction did not effect reading scores, but did effect math, creative thinking, and perceptual motor scores in high achievers and males in the first grade. Ross, Ross, and Kuchenbecker (1973) stated their collective view on the importance of rhythmic skills to the EMR child: The ERM child's difficulty in activities such as jump- rope and pegboard races is frequently due to his inability to maintain a rhythmic tempo rather than to inability to perform the specific responses of jumping in place or loading pegs. The ability to respond rhythmically is of considerable importance to the psychological well-being of the EMR child; it is prerequiste to success in play activities, sports, and social dance; it helps to prevent fatigue and promote a feeling of control; and it is of particular importance for success- ful performance in the vocational tasks such as typing, machine work, and small parts assembly that the EMR child is likely to perform in adulthood. 21 Dr. John S. Rowlson, in a personal interview, commented about his clinical observations of mentally retarded clients in the therapeutic work environment of Bretton Square Industries. He stated that it appears that when rhythmic flow in a manual job function is interrupted, the efficiency'hsdisrupted. In the physical efforts of those who produce in quantity, there is a fluidity of movement. There are fewer wasted motions and less deliberation between movements. Rowlson pointed out two skill areas necessary for the successful performance of the manual jobs at Bretton Square. The first is the mechanics of the job, and the second is timing. For example, in mopping, a figure eight pattern is taught, and rhythmic execution becomes a part of the skill. In a paper collating task, a sense of rhythm is helpful. On the stamping machine, the most successful clients demonstrate rhythm. The ninety mentally retarded adults who work at Bretton Square Industries range in age from twenty-six to seventy-three and in IQ from approximately 16-20 to 88. All clients work in a large, open room. On several of the jobs the machines impose a constant, timed sequence of mechanical sounds. On many days the staff have reported that the shop "hums" auditorily and behaviorally as the separate job processes begin to coincide. At these times conversation proceeds smoothly and behavior problems are fewer. At the clients' request, music is played in the work environment throughout the day. It has been observed that when the volume becomes too loud, behavior problems increase. This is believed to be the result of the music having the effect of additional noise. When the shop is under stress, the music is often felt to be annoying. 22 With regard to music choices, clients found soothing music to be boring and moderately stimulative music to be most preferred. Some of the clients use personal radios with earphones while working, and the motor rhythm of their job performance seems to be influenced by the music to which they are listening. (Rowlson, 1983) In the area of speech skills, Gibson (1978) referred to the work of J.B. Share in the following quote on the importance of motor control skills: It can be fairly contended that lateralization and motor control delay are related to delayed speech (Share, 1975), whether the subject is Down's or not. Any procedure which would hasten motor coordination, such as patterned exercise, might advance the establishment of cerebral dominance and therefore of speech readiness. These possTBilities have not been adequately explored for the 05 child. Down's Syndrome Identification of the Syndrome In his book, Down's Syndrome (1978), David Gibson has enumerated the viewpoints and research that have contributed to the currently accepted description of this disorder, originally called mongolism, first identified by Langdon Down in 1866. The condition is a chromo- somal abnormality that is identified by both clinical manifestations and by abnormal genetic configurations. Clinical diagnosis of DS is made through the observation of all or some of the following somatic signs, often referred to as the thirteen cardinal indices of mongolism: 1. High cephalic index Abnormal nostral direction Abnormal toe spacing Short fifth digit’ 01wa Curved fifth digit 23 Square hand Epicanthic fold Fissured tongue LDCDNCW Simian crease 10. Single fifth flexion 11. Abnormal ear 12. Adherent lobule 13. Abnormal heart Genetic determination of the disorder is made through genetic testing of body cells (karyotyping) that reveals the presence of extra chromosomal material. Three karyotypes have been identified: standard trisomy, the most common, the result of three number 21 chromosomes instead of two; translocation trisomy, the result of some chromosome 21 material attaching to chromosome number 15; and mosaicism, the result of some abnormal and some normal cells in one individual. Mental Development The developmental characteristics of DS seem to follow a generally predictable pattern. However, Gibson (1978) cautions against the temptation to overgeneralize: "Despite the stereotypic uniformity of the syndrome, the most striking feature is its developmental 3331a- 13.111191 "13 During the first few months of life DS infants show near normal mental growth. While subsequent mental growth follows the usual develop- mental seqUence, the rate falls behind that of their normally developing CA peers (Carr, 1970; Gibson, 1978). Mental growth has been known to continue as long as age twenty, but usually at about age eleven it ceases, and a gradual deterioration begins to occur. This decline takes 24 the form of pre-senile dementia and frequently is exacerbated by Alzheimer's Disease. DS mental growth appears to proceed in plateau stages, even more than for normal children. These stages are: Growth Stage I 18-4 years CA reaching 17 months MA Growth Stage 11 5-9 years CA reaching 31 months MA Growth Stage III 11-12 years CA reaching 40 months MA14 The second stage is generally the limit of expected mental growth, covering a range of two to three years of MA for the majority of 08. Early studies found the majority of DS to test in the 20-40 IQ range, with the next largest group falling below 20. 10's as high as 66 occurred infrequently. While most studies were conducted on institutionalized DS, Wallin (1944) began to look at DS children in the community and to challenge earlier conclusions. Gibson (1978) noted that the variability of results between studies, attributable to differences in age at testing, nutritional and health status and institutional selection bias, had not been explored by any of the early investigators. Consequently, reliable conclusions as to dimensions of intelligence for 05 were not possible, even up to 1950. More recent investigators sampled more community and institutional- ized DS and generally reported a somewhat higher 10 range. Quaytman (1953) found that while 75% of her home-based sample were below 50 IQ, 25% were above, the majority of them still below 70 IQ. Cornwell and Birch (1969) found most of their community based sample fell between 23 and 69 10. They noted that higher IQ's occurred more often in younger rather than older cases. In summary, Gibson (1978) said, "the distribution of IQ for DS seems to centre at mid-imbecility (TMR), 25 with a large minority grouped in the custodial category and a not-so- large minority within the educable class."15 The beginning development of conceptual-symbolic mental skills appears to be a barrier to further mental growth for the vast majority of DS persons. Most do not develop the ability to use abstract thinking processes. While the evidence is not totally conclusive, the available statistics point to a generally higher intelligence in female 05 than in males. Females also have a higher infant mortality rate, and males seem to be more susceptible to secondary illnesses as they develop, circumstances which may result in the survival of healthier, more intelligent females. Physiological Characteristics Common physiological deficits in the syndrome, in addition to their premature neurological deterioration, include a weak cardiovascular system, reduced sensory functioning, and hypotonia, a generalized state of muscle flaccidity. Susceptibility to respiratory infections is secondary to structural characteristics of small oral and nasal passages and weak diaphragm muscles. There is a generalized condition of premature physical aging, accompanying the early onset of progres- sive intellectual decline. In physical stature the US person has shorter than normal bone structures, especially noticeable in distal ends of the long bones of the arms and legs, as well as those of the hands and feet. They are shorter in overall height, a characteristic that shows an increase in proportion to normals as they grow older. In the twelve to eighteen- year-old group, 73% are below normal height. Based on height, many 05 individuals are overweight.16 26 Smith and Berg (1976) reported early surveys of mortality in OS. A 1958 study showed that 30% died by one month of age and 50% by one year. Later reports still indicated that 03 death rates are highest during the first four to five years of life. By 1970 approximately two-thirds of DS children lived past age ten. A major factor in D8 mortality is the high incidence of congenital heart disease (60%). Average lifespan has increased from nine years of age in 1932 to over thirty by a 1973 survey; the upper expected age is around fifty-five years.17 Personality In personality traits DS have been characterized as having cheer- fulness, good disposition, obedience, and independence on the positive side, and having communication disorder, stubbornness,short attention span, attention seeking and easy fatigue on the problem side. A 1966 institutional study in Arizona and Washington indicated that DS exhibited significantly less aggressive maladaptive behavior than other mentally retarded patients (Moore, Thuline, and Capes, 1968). Negative behavioral changes, detected as the child grows older, seem to coincide with two developmental events; a failure to bridge concrete to conceptual styles of intellec- tual expression, and an absence of language skills appropriate to the expectations of advancing age. Both the ability to abstract and relate interpersonal events, and a suitably matched advance of communication skills, are critical to positive growth and maintenance.18 Though not observed in all cases of DS, Gibson stated the following concensus view by the writers he reviewed regarding characteristic personality development: . . the placid, sensorially insufficient infant becomes an emotionally intact and outgoing child who turns subsequently into a sullen adolescent and finally faces premature aging and marked behavioral deterioration in early adulthood.19 27 The nurture of a home environment over that of an institutional setting seemsixabe a significant factor in personality, as well as total devel- opment (Carr, 1970). Speech and Language 08 speech often shows a defect, particularly in the articulation of speech sounds, and a generally nasal, breathy, hoarse voice quality. This is thought to be a result of structural traits including a short- ened oral cavity, dryness and protrusion of the lips and tongue, and underdevelopment of the sinuses and nasal passages. Speech and language development is also influenced by character- istic hearing and visual impairments, found to be higher than normal in this syndrome. Carr (1970) reported a study by Lyle in 1959 in which DS individuals made less progress than other mentally retarded persons in speech when moved to a more stimulating environment. In language use, US persons show . . a preference for certain parts of speech over others [hounS], a better verbal understanding than word use, a tendency to emphasize the first consonant and vowel sounds of words and a Bropensity to communicate with a minimum of verbal complex1ty.2 In Gibson's (1978) view the 08 persons' language and communication patterns are caused by a combination of mechanical (structural), sensorimotor, and central nervous system anomalies, the last of which is in a deteriorating process as the first two show some improvement with growth. Other possible factors include slow reaction time, depressed arousal potential, and reduced attention span. 28 Sensorimotor In sensorimotor areas the 08 person shows the strongest performance in the areas of visual decoding or reception (understanding pictures of low verbal content) and motor encoding or expression (conveying thoughts by gesture), with the most sensory deficit in the area of auditory channelling. This appeared clearly in a 1965 study comparing DS to each other by Bilovsky and Share as reported by Gibson. They are also described as having good motor strength and superior early self-help skills. He points out that this evidence is most convincing for DS children prior to late adolescence and adulthood. Motor poten- tial in OS appears good in infants but erodes rapidly from the norm after the first year. It is a general concensus from most research that reaction time in OS is slower than normal as well as slower than that of other non- DS mentally retarded people. Gibson (1978) pointed out, however, that the conclusions as to cause of slow reaction time are quite variable, including: 1. Cerebellar originated hypotonia Conceptual handicap (cognitive) Sensory or perceptual handicap (auditory discrimination) High arousal thresholds (to stimulate attention and drive) LII-DOOM Motor impulsivity differences Davis and Kelso (1982) compared normals to DS and concluded that the neuromuscular system employed in gross motor movement was similar for both groups. However, they reported a notable difference in response to changes in weight loads on static muscle/limb position. 03 showed a greater degree in the angle of overshoot when adjusting to weight added to a mass held steady by the subject's finger. 29 With regard to discrimination skills, Gibson (1978) reported a concensus in the literature that 05 people are lower in ability than other mentally retarded for stereognostic, kinesthetic, and tactile shape discrimination and possibly for auditory-vocal channelling. However, they are claimed to be equal to or higher in ability than other mentally retarded for visual-stereognostic, visual-tactual discrimination, and for visual exploration potential. Attention span difficulties, related to high distractibility and impulsivity, is also generally accepted regarding 08, though not appreciably more than for non-DS retarded. The total picture of the DS person's traits and abilities seem to rest on an interaction of effects from three major areas: central nervous system deficits, peripheral sensorimotor characteristics, and unique physiological (structural and medical) conditions. Studies of Rhythm and Motor Skills in OS Early opinions on the rhythmic abilities of 03 persons held that they possessed a "marked sense of rhythm" (Tredgold and Soddy, 1956) and a heightened sensitivity to music in general (Shuttleworth, 1900; Brushfield, 1924; Wallin, 1949). Though more recent research has not supported this belief (Cantor and Girardeau, 1959; Fithatrick, 1959; Peters, 1970; Frith and Frith, 1974), there exists the lay impression that dance, rhythm, and melody skills are "inborn" in 05 (Gibson, 1978). Even many non-music health professionals still attribute a high level of rhythmic ability to 05 persons in general. Martha Peters (1970) studies 03 children in comparisons with normals matched for chronological age, IQ, and mental age. When matched 30 by mental age, OS of sixteen years of age were compared to six-year- old normals, and six-year-old DS were compared to three-year-old normals. The 08 mean IQ was 38. She measured musical sensitivity by responses to musical variables such as stimulative and sedative music; music that was predominantly harmonic, melodic, rhythmic, or dissonant in character; orchestral and piano music; and clapping and singing activities. In her findings she noted a lower score of musical responsiveness in 05, though statistical significance was not achieved. DS subjects scored lower in imitation skills when matched with normals of the same chronological age or of the same mental age. DS subjects of all ages tended to respond most like the very young normals. In rhythmic abilities the sixteen-year-old 03 tested similarly to three-year-old normals. All groups showed a high preference for rhythmic music and little preference for singing (except for normal six-year-olds). For clapping activities younger 03 showed a lower responsiveness and older DS showed higher. The study was difficult to evaluate as the test appeared to be quite short, little data was reported, and the definitions of the variables were not clear. In 1959 Cantor and Girardeau reported their investigation into the DS person's ability to discriminate and identify fast and slow tempi. The fast (120 beats/minute) and slow (88 beats/minute) stimuli were provided by metronomes placed out of the subject's sight. Once the subjects demonstrated verbally that they recognized and could label the two rates, the testing was conducted. Half of the subjects were instructed to tap with one finger on the table as they listened to each of the sixty tempo items, while the others were instructed to simply 31 listen. Forty-four DS and twenty-four normals of nearly matched mental age were tested. Fifteen of an original group of fifty-nine 05 subjects were eliminated, seven due to unintelligible speech and eight due to lack of cooperation. While the DS subjects scored significantly better than that expected by chance, the normals discriminated significantly better than the DS. The Tapping groups did no better than the No-Tapping groups. However, the researchers noted that very few of the subjects were capable of tapping in reasonably good time, and that the activity may have interfered rather than facilitated accurate tempo discrimination Fithatrick (1959) conducted two experiments concerning the rhythmic motor skills of severely retarded subjects. The first study, designed to simply explore the rhythmic nature of the DS person's movements, involved the repeated bilateral folding of two levers from a vertical to a horizontal position. Twenty subjects of the same mental levels (4.1 years mental age), ten DS, and ten unclassified mentally retarded hospital patients, performed the movement for twelve periods of ten minutes each. Periods were divided into two-minute segments, alter- nately accompanied by a metronome ticking at 110 beats/minute and without any accompaniment. The speed of folding was measured and compared to the metronome tempo. Half time and double time rates of response were given credit. Fitzpatrick found no significant difference between the two groups, either in output or in regularity. The intervention of the metronome had no benefit on performance, but actually tended to make responses more erratic. The experimenter interpreted the results to suggest that 05 individuals do not have particularly strong rhythmic skills. 32 Fitzpatrick's second experiment involved severely impaired hospitalized patients, non-OS, and the effectiveness of three different interventions to aid their performance on a group work task. They worked in groups of three on a task of folding large pieces of poly- ethelene in a prescribed manner. The three conditions under which they worked were: (1) at their own pace, (2) with music and, (3) with a caller chanting the instructions for the job. The third condition proved to be significantly better at improving their work output. Frith and Frith (1974) studied specific motor disabilities in D5 subjects by using comparison groups of normals and severely subnormal autistic subjects matched first for mental age and then for performance on a rotary pursuit tracking task. The sample was structured in this manner so that performance effects could be better sorted out as attributible to DS in particular rather than simply to their subnormal mental conditions. Two motor tasks were used in the testing: (1) rotary pursuit tracking, which requires the learning and usage of motor pro- grams for successful execution of the skill and (2) tapping, which involves little or no learning. It was anticipated that performance of these two tasks would help permit the distinction between impairments of performance and impairments of learning. Rotary pursuit tracking is measured by the amount of time a subject can keep a photoelectric cell, attached to his/her finger, on a patch of light moving in a circle on a flat surface. Subjects tracked for two periods of three minutes, with a five minute rest in between. Performances by OS subjects showed a mean tapping speed (113 beats/minute) significantly slower than either of the other two groups. They had higher tapping variability associated with higher tapping 33 rate; the other children did not. US also showed no improvement in tracking after the five minute rest; the autistic children did. Frith and Frith concluded that 05 persons maintain motor control by responding to immediate perceptual feedback rather than by devel- oping motor programs by which rapid, regular movements can be anticipated and accurately followed.- This is a difficulty compounded by generally slow reaction time, as well. The researchers conclude that "mongol children should do relatively well in motor tasks requiring slow movements following no predetermined course but relatively badly at tasks involving fast and regular movements."21 Summary Rhythmic synchronization has been of interest to researchers for several decades. It has been studied both by inference from observation and by formal testing using electronic instrumentation, mostly with normal populations. Performance, rather than discrimination, measures are generally recommended to test this motor skill area. The findings indicate that synchronization skills are not fully acquired until approximately age seven, and that, in the tempo range of 60-182 beats/minute, subjects tend to synchronize better at the faster tempi. It is not clear from the research studied whether performance is better at a tempo chosen by the subject. Down's Syndrome individuals are generally in the TMR range of intellectual functioning and have motor and sensory deficits that most likely affect their rhythmic skills. They are stronger in visual than auditory discrimination. Despite their acknowledged attraction to music activities, the research literature does not support the idea that they possess outstanding rhythmic skills. CHAPTER III METHODOLOGY sample The sample studied in this investigation consisted of subjects identified as having Down's Syndrome. All lived in community-based foster care or group homes, or at home with their parents. The major- ity were involved in school special education programs (if under twenty- six years of age), or in community mental health activity or work programs (if over twenty-six years of age), as prescribed by Michigan laws on public education for the handicapped and the mental health code. They ranged in age from eight to forty-eight years old, with a mean age of 21.2 years. Twelve were males and nine were females. Of the twenty-one subjects, IQ scores were available on nineteen; the mean leas 43. Thus, the majority of subjects were in the TMR classifi- cation, with four testing in the low EMR range and one at the top of the severely mentally retarded range (See Appendix A for a breakdown of the demographic figures on subjects.) Any potential subjects who had a diagnosed major motor, physical, or health impairment in the categories that follow were eliminated from the study: cerebral palsy, muscular dystrophy, multiple sclerosis, severe hearing impairment, legal blindness, or amputation, paralysis or deformity of the upper extremities. 34 35 Inasmuch as musical training could alter the level of rhythmic ability demonstrated by the subjects, the study limited the sample to DS individuals who had no specific formal training in music, such as individual music lessons on a single instrument or voice for a year or more. It was thought that participation in school music classes or music therapy treatment in which motor development was not_a specific goal would not exert a significant influence upon the results of this study, since random assignment to experimental conditions would control for varying musical experiences among the subjects. Many of the school-aged subjects were drawn from the Ingham Inter- mediate School District facility for the handicapped in Mason, Michi- gan. The rest were contacted through their participation in Greater Lansing community music groups for the handicapped and through the Michigan State University Music Therapy Clinic. In order for subjects to participate in the study, they and their parents or guardians had to agree to come to the testing site on the campus of Michigan State University. DiSisLn. The design for this study incorporated a one-way analysis of variance to test the significance of differences between the means of three different treatment groups. Each of the twenty-one DS subjects were randomly assigned to one of three groups. Each grouping repre- sented an experimental condition (treatment) in which the subject was tested at one of the following tempi: 1. 9O beats/minute (Group A) 2. 150 beats/minute (Group B) 3. a tempo spontaneously chosen by the subject (Group C) 36 The random selection for each group was achieved by assigning each subject to one of the three conditions in turn as the testing proceeded. This was intended to equalize the groups so that the main effect of the independent variable (tempo) could be observed through the measurement of the dependent variable (synchronization score) and compared among the three groups. Data for the other independent variables under investigation (intelligence and age) were collected as IQ scores from the most recent psychological testing available and as dates of birth for each subject. These scores were correlated to synchronization scores to study the relationship between intelligence and synchronization skills and between age and synchronization skills. Setting and Procedure Each subject was tested one time, during a fifteen-minute music session. The experimenter conducted all of the testing sessions on a one-to-one basis with each subject. The setting was a well-lighted, quiet, carpeted, partitioned laboratory. Atable with the electronic measurement equipment was at one side of the medium-sized room, and the technical assistant was seated next to it. An electric piano was at the sidecnithe equipment and was played by an additional assistant during only the "tempo of choice" condition. The subject and experimenter sat in chairs facing each other, with the subject's back to the equipment. The rhythmic motor task used to test rhythmic synchronization con- sisted of playing with a single mallet on a freestanding, twelve-inch, tunable drum placed between the subject and experimenter. The playing surface was slightly below waist level for the seated subject. The mallet was offered to the subjects at the midline and each subject 37 played with whichever hand he/she preferred. The subjects were in- structed to play on the beat of the music they would hear during the training and testing segment of the session. The testing session followed the four-step format described below: 1. A warm-up musical activity of easy movement and body percussion to help acquaint the subject with the experimenter and put the subject at ease 2. A set of four training examples to teach the subject the drum playing task to be performed with music at the appropriate tempo: Example a) Experimenter demonstrated the drum playing task; subject observed Example b) Experimenter and subject both played on the same drum; total task was modeled and cued by the experimenter Example c) Experimenter and subject both played; task was modeled by the experimenter at the beginning, but faded out about one-half of the way through; only verbal encouragement used thereafter Example d) Only subject played; verbal encouragement used if necessary 3. A test item at the experimental tempo, the subject alone playing the drum 4. An untested activity of the subject's choice, to wrap-up the session (e.g., sing a favorite song, play an instrument, etc.) (See Appendix B for an example of the narration used in instructing each subject throughout the testing session.) 38 After the first seven subjects were tested a brief segment of exploratory drum playing and a short tapping test of the subject's fastest speed were incorporated immediately prior to step 2. This procedure resulted from a question regarding the capability of some subjects to actually play as fast as 150 beats/minute. This was initiated to help explain the possibility of extreme deviations from the beat at the fast tempo. The recorded musical stimulus consisted of the following events, all at the given tempo: eight beats of metronome clicks; eight beats of metronome clicks with "one, two, three, four, one, two, ready, go" spoken over them; and either (a) thirty-two beats of piano music at 90 beats/minute (21.3 seconds in length) or (b) forty-eight beats of piano music at 150 beats/minute (19.2 seconds in length). All of the music used was composed and performed by a professional pianist to provide a strong rhythmic pulse on every beat, in popular harmonic style, but with only a few passing notes played for musical continuity on the subdivisions of the beat. The tempo of choice condition was constructed in the following manner: for each of the four training items and for the test item, the subject was directed to begin playing at any speed he/she wanted; a pianist assistant set a metronome at the resulting speed; the experimenter asked the subject to stop playing and then counted "one, two, three, four, one, two, ready, go" with the metronome; the pianist assistant played a short composition of a character similar to those mentioned above with the tempo of the metronome as the standard for the test item, as the subject played on the drum. The sixteen beat musical composition was played twice through for tempi chosen that were 39 120 beats/minute or lower, and three times through for tempi above 120 beats/minute. (See Appendix C for the musical examples used in the three conditions.) For the present research a moderately slow tempo of 90 beats/ minute was chosen to avoid the tendency to subdivide very slow tempi and to provide a feeling of musical continuity in the music which was composed purposely to emphasize only the beats, with very few extra notes between them. The tempo of the subject's choice is an experi- mental condition believed by this researcher to be influential in the success of motor synchronization for 05 individuals. This belief has arisen from clinical observations in which 05 people appear to maintain steady beats, but not necessarily at the speed of the musical stimulus at hand. Measurement The measurement apparatus used in the study was a two-channel chart recorder, model 1200, manufactured by the MFE Corporation of Salem, New Hampshire. It was chosen for its accuracy and permanence of record. It registered each the stimulus and the response through the deflection of a stylus on a paper roll moving at a rate of 100 mm/second. At that rate, it gave an accurate measurement to within .01 second. One channel made a record of the music stimulus, either played on the cassette tape recorder and fed in electronically by way of an amplifier, or played on the electric piano and electron- ically fed directly into the chart recorder by way of a small, ceramic crystal microphone taped inside near the head of the drum. Synchronization scores were calculated to the nearest hundredth of a second in two ways: 1. as the mean deviation of the subject's 40 response beat lengths (RBL) from the stimulus beat length (SBL) at the given tempo and 2. as the deviation of the subject's mean RBL from the SBL of the given stimulus. The measurement of responses began after the first eight beats of music, in order to avoid penalizing subjects when making any necessary adjustments to regulate their initial motor responses. The subsequent twenty-four beats were measured. Synchronization score category 1 was determined for each subject by subtracting the SBL from each RBL in the tested twenty-four beats of music. The highest and lowest deviations were discarded and the mean deviation was computed from those remaining. Absolute deviations (without regard to positive or negative sign) were used in this compu- tation so that deviations on opposite sides of the SBL did not cancel out each other's value. Synchronization score category 2 was determined by subtracting the SBL from the subject's mean RBL. Figured in this manner, a nega- tive score indicated a beat length shorter than the standard, and therefore indicated a response that tended to rush ahead of the beat on the average. A positive score indicated an elongated beat length, and consequently a response that lagged behind the beat on the average. By the same principle, the group mean synchronization scores in category 2 indicate the general direction of error in synchronization within each tempo condition. Because of the closeness and small size of the scores, all subject and group mean scores were expressed in thousandths of a second after computations were completed. A tolerance of 1.01 second was removed from each score to allow for the average error found in the recorded stimuli at both 90 beats/ minute and 150 beats/minute. For the tempo of choice, the tolerance was calculated separately for each subject's test, as the musical 41 stimulus was played and recorded live each time. The tolerance in that tempo condition ranged from i.01 to t.02 with a mean error of $.01. Special Considerations Testing of handicapped subjects can create special concerns about reliability and validity of the testing method. The following factors were considered particularly important: the subjects may be inhibited, frightened, or uncooperative due to the strangeness and unfamiliarity of the setting, the experimenter, or the apparatus used; and the handicapping condition may complicate the conveyance of instructions and the subsequent performance by the subject (Bixler, 1968), espec- ially if communication or attention span are impaired (Cantor and Girardeau, 1959). Consequently, for this type of research, testing procedures must be clear, uncomplicated, and well-paced, and testing media must be interesting and motivating. Additionally, the setting must feel supportive, congenial, and comfortable for the subject. This study attempted to anticipate and accommodate for these particular characteristics involved in testing the handicapped through these provisions: 1. The musical stimuli used emphasized the beat clearly and strongly 2. The music was rhythmic and popular in style to help maintain attention and interest 3. Instructions proceeded in small progressive steps, primarily through demonstration, with a minimum of verbal information 4. The procedure kept the subject active throughout most of the session, which was short (fifteen minutes) 42 5. Encouragement and support, both verbally and non-verbally, was maximized as appropriate, beginning with an easy, comfortable activity and ending with an activity of the subject's choice, both of which were unencumbered by concern for measuring the behavior 6. Playing the drum, generally a popular and motivating instrument, was the media for testing motor response; the drum had no obvious testing apparatus attached, and the subjects needed no distracting apparatus attached to them Pilot Testing The testing procedure and the paper recording device were pilot tested. The experimenter's responses to the stimulus were used to determine preliminary adjustments of the apparatus and to practice the scoring techniques. Following this, a mentally retarded subject was tested on the complete procedure, using the 90 beats/minute tempo for the testing segment. Finally, a university percussion major was tested on all three tempo conditions. W A one-way analysis of variance was performed on the data to deter- mine if there were statistically significant differences in the mean performance scores of the experimental groups. That the effects of the tempo variable could be attributed to chance was determined through this analysis. To study the relationship between IQ and rhythmic synchronization, a rank-order correlation was calculated on the synchronization scores and the IQ's of nineteen of the twenty-one subjects for whom 43 intelligence testing was available. A rank-order correlation was also calculated on synchronization scores and chronological age in months. Summar Twenty-one 03 subjects, averaging 21.2 years in age and 43 points in IQ, were each randomly assigned to one of three experimental tempo conditions: 90 beats/minute, 150 beats/minute, or choice of tempo. They were tested in the performance of a motor synchronization task that consisted of playing a drum to a musical stimulus of piano music. The stimulus and motor responses were recorded on a two—channel chart recorder. Deviations of the response beat length (RBL) from the stimulus beat length (SBL) were calculated and the mean differences were compared across experimental conditions and in relation to IQ and age. A one-way analysis of variance was used to determine the statis- tical significance of the results, and rank-order correlations were computed on the synchronization scores and both IQ and age. CHAPTER IV RESULTS Findings This study measured rhythmic synchronization response to an ex- ternal stimulus in 03 persons by recording and comparing the response beat length (RBL) of the subject to the stimulus beat length (SBL) of music played at one of the three tempo conditions. The raw data and demographic information for each subject and group are included in Appendix A. Subject #7, in Group A, responded at an almost perfect double- time tempo in the testing. The mean RBL was .318 second as compared to the SBL of .635 second. This was actually faster than the tempo demonstrated in the tapping test in which the subject was asked to play as fast as possible (beat length of .368 second). Due to the small sample size, the resulting scores for this subject inflated the Group A figures to a degree that appeared unrepresentative of the group's actual performance. This circumstance also greatly increased the dif- ferences between the mean scores of Group A and the other two groups, possibly giving the illusion that this experimental condition had a greater effect on performance than was reasonable to imply. Therefore, rather than assuming that the response was either highly synchronized but simply double-time or poorly synchronized, the subject's data were eliminated from the statistical analysis. 44 45 Due to differences in tempo calibration between the metronome used as a standard when recording the musical stimuli and the tempo as calculated from the chart recorder, 90 beats/minute was actually 94 beats/minute, and 150 beats/minute was actually 155 beats/minute. For the purposes of reporting and discussion, however, they will continue to be referred to as 90 and 150 throughout the paper. The tapping speed test that was incorporated into the session for the last fourteen subjects revealed a range of tempi from 114 to 337 beats/minute. The purpose of this test was to verify that the subjects were, in fact, capable of responding at or above the speeds requested of them. Only one subject, #14, demonstrated a maximum tempo that was slower than that of the experimental condition in which the subject was placed. This same subject responded during the synchronization testing with a shorter beat length, and consequently a faster tempo, than that imposed by the external stimulus. 'Hwameandeviation of the RBL's from the SBL was calculated for each subject (synchronization score category 1), as well as the devia- tion of each subject's mean RBL from the SBL (synchronization score category 2). In Table 1 the group means for these two synchronization categories are given. A one-way analysis of variance was computed on the scores which consisted of the mean deviation of the RBL's from the SBL (score 1). 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