Percefitual and Motor Skills, 1976, 42, 215-219. @ Perceptual and Motor Skills 1976
PERCEIVED AGE A N D SEX CHARACTERISTICS OF VOICES OF INSTITUTIONALIZED CHILDREN W I T H DOWN'S SYNDROME JAMES C. MONTAGUE, JR.'
University of Arkansas at Little Rock Summary.-It was hypothesized that the voices of children with Down's syndrome would be perceived as younger than their true chronological age and that perceptual auditors would have considerable difficulty in identifying the correct sex of these children by voice alone. Perceived age and sex were investigated in 2 0 institutional children with Down's syndrome who were matched for sex and age with a control group of 2 0 normal children. Randomized matched verbal samples were played backwards to a group of 16 listener/judges who rated the samples as to age and sex. The results indicated that the voices of these Down syndrome children were perceived as being more than 2 yr. younger than their group mean age and that there was a negative correlation between the biological sex of such children and their perceived sex.
It has been reported (Blanchard, 1964; Benda, 1969) that children with Down's syndrome have deviant voices. To test these clinical impressions of vocal problems, a limiced number of objective acoustical and perceptual studies have been conducted in recent years. Generally speaking, the majority of the acoustical studies (Michel & Carney, 1964; Hollien & Copeland, 1965; Montague, Brown, & Hollien, 1974) showed the fundamental frequency for children with Down's syndrome to be essentially like those of normal children of the same CA. A somewhat different finding was reported by Weinberg and Zlatin (1970) who reported the speaking fundamental frequency levels of preschool children with Down's syndrome showed significantly higher speaking fundamental frequency than those of the matched sample of normals. However, the WeinberdZlatin sample with Down's syndrome was different from those in other studies, i.e., their subjects were controlled for specific genetic aberrations within Down's syndrome, were younger, and came from noninstitutionalired environments. Montague and Hollien (1973) objectively studied perceived voice quality deviations of 20 Down's syndrome and 20 normal control children. Their results showed chat children with Down's syndrome exhibited significantly more breathiness and roughness than did the normal group. More nasality was observed in the group with Down's syndrome than for normals, although che data were somewhat variable. To date, no studies have been conducted on the judgment of age and sex of children with Down's syndrome by voice alone. Deviant voices in children with Down's syndrome, with regard to perceived age and sex, might provide baseline data against which later biological or behavioral intervention strategies 'Address all correspondence to J. C. Montague, Jr., Speech and Hearing Clinic, Universiry of Arkansas at Little Rock, 33rd and University, Little Rock, Arkansas 72204.
216
J. C. MONTAGUE, JR.
might be measured. It has been well established (Benda, 1969) that these children are "unfinished children" with respect to the physical attributes of age and sex development by comparison with their normal peers. As a group such children ate shorter and smaller, and their sex organs are retarded in develop ment. Thus, it was hypothesized that the voices of Down's syndrome children would be perceived as being younger than their actual chronological age. It was further hypothesized that the listener/judges would have considerable difficulty in identifying the correct biological sex of the children with Down's syndrome by voice alone. METHOD Subjects One group was composed of 20 subjects medically diagnosed as Down's syndrome and selected from an institutional population; the control group contained 20 normal children selected from a local public school. The two groups were matched on the basis of sex and chronological age as well as chronological age within sex on an individual basis. Individuals in the retarded group had been institutionalized for an average of 6.27 yr., with a range from 7 mo. to over 12 yr.; their records showed an IQ range of from 17 to 58, with a mean IQ of 32.2. An additional independent variable of importance was hearing sensitivity. As noted in the hard-of-hearing and deaf, elevated heating thresholds may affect auditory self-monitoring and produce deviate vocal characteristics. A modified bilateral-ear choice technique, as developed by Kurtzrock (personal communication, Univer. of Florida, 1970), was utilized for auditory evaluations. The frequencies tested were 500, 1000, and 2000 Hz (ISO) ; Beltone portable audiometers, Models 12-A or 9-D, were utilized. The children with Down's syndrome were tested in a sound-treated room located in the Speech and Hearing Clinic on the institutional grounds. Hearing of the normal group of children was assessed in a quiet conference room in the school; slightly more ambient noise was noted during testing of the normal group. All 20 of the control subjects and 14 of the experimental subjects were reliably conditioned for hearing testing ( 6 children with Down's syndrome could not be conditioned, thus were not tested). The group with Down's syndrome had International Standards Organization mean hearing thresholds of 33.7 db at 500 Hz, 31.6 db at 1000 Hz, and 33.0 db at 2000 Hz. The pure tone threshold data for the control group was 19.7 db at 500 Hz, 8.2 db at 1000 Hz, and 4.0 db at 2000 Hz. As evident, the hearing thresholds of the children with Down's syndrome were somewhat higher than the normals. These hearing thresholds are similar to those reported by Deloach (1968) in her study of auditory acuity in mongoloids.
Voice Sampling Procedure It was judged essential that strictly matched verbal samples should be
CHARACTERISTICS OF VOICES AND DOWN'S SYNDROME
217
obtained from both groups. To accomplish this matching, a strategy was developed for eliciting identical single-word utterances from all subjects in both groups. Accordingly, 18 large black and white pictures of common subjects, such as "dog," "cat," "man," "woman," etc., were drawn and used as stimulus materials. The recordings of the subjects' responses were made in the same quiet environments used in the hearing testing. The examiner, sitting next to the subject, presented the stimulus picture while simultaneously saying the word; the subject so encouraged, responded verbally by repeating the appropriate word. After a brief training session, responses were obtained from the subjects for all 18 of the stimulus pictures. This combined visual/aural stimulus approach proved quite effective for eliciting the desired word samples from both groups of children. The verbal samples were recorded at 7.5 ips on an Ampex (Model 601 ) tape recorder coupled to an Electro-Voice (Model 664) microphone.
Analysis of Data The original tapes were dubbed and three words, "boy," "baby," and "doctor" were spliced from each subject's tape into a sequence with approximately 2-sec. pauses between them. A table of random numbers was used to order the 40 grouped responses from the 20 children with Down's syndrome and 20 control subjects; a second randomization of these 40 stimuli was added to the first. Following each of the 80 three-word sets, a 4- to 6-sec. pause was placed on the tape to allow sufficient time for the judges to make their perceptual decisions. Of concern was the possibility that other verbal components (besides age and sex characteristics) might influence the ratings. Specifically, the probability existed that the subjects with Down's syndrome would exhibit defective speech (misarticulation and the like) and thus influence the judges' ratings. To control this possible bias, all samples were played backward (see Sherman, 1959). Finally, to eliminate perceptual cues from identifiable noise on the tapes, all taped samples were processed through an 18-db per octave filter bandpass of 150 to 4000 Hz.
Judging Procedure Judges were 16 paid undergraduate students. The listening session was conducted in an acoustically treated classroom in the Communication Sciences Laboratory at the University of Florida. The stimuli were presented via a Model 602-1 Ampex recorder with an associated Model 622 Amplifier/speaker system. Prior to the listening session, a speech-discrimination test (CID Auditory Test-22) was administered to all listeners; no volunteers failed this test. At the initiation of the listening task, the judges were told that they would be listening to a series of children's voices and were asked to make judgments relative to each child's sex and age. On the judges' sheets, for each of the 80 sets of stimuli, were dichotomou~male/female choice blanks and eight scaled age-choices; running from age 6 to 13. The judges listened to the entire 80
2 18
J. C.
MONTAGUE, JR.
sets of stimuli making their male/female judgments and then listened to the tape again to make their final perceived age choices. The entire rating procedure took less than 1 hr. At no time were the listeners given any suggestion that many of the samples they were listening to belonged to children with Down's syndrome. RESULTSAND DISCUSSION An analysis of variance, utilizing a correlation derivation (Winer, 1971), was used for computing the intrajudge reliability on the age ratings for the 16 listener/judges in comparing their first versus last sets of 40 ratings. Positive intrajudge correlations of .64 and .67 were computed respectively for the normal and Down's syndrome children. While only moderate, these positive correlations suggest that there was reasonable agreement within each judge's auditory perceptual judgments of the ages of normal and retarded children. Interjudge reliabilities of the age ratings were also positive, with .55 reported for the normal group of children and .82 for the children with Down's syndrome. It is interesting to note that among themselves the listener/judges apparently were more in agreement with respect to the ratings of age of children wich Down's syndrome than of the normal children. The mean rating of age for the normal children was 10.45 yr., with an S D of 1.78, whereas the children with Down's syndrome were rated 8.17 yr., wich an SD of 1.81. The mean age of the normals, 10.45 yr., coincided with their actual mean age CA of 10.41 yr. reported in Table 1. However, the children TABLE 1 SEX, MEAN, AND RANGE OF CHRONOLOGICAL AGE FOR Group Male Down's Syndrome Control
10 10
Sex Female 10 10
M 10.42 10.41
-0
GROUPS
Chronological Age Range 7.75 to 13.50 8.00 to 13.25
with Down's syndrome were perceived as being approximately 2.25 yr. younger. This appears to confirm the hypothesis that the voice of the child with Down's syndrome is perceived to a large degree as being below his/her chronological age. This may be attributed to one or more deviant physiological parameters unique to this group of retarded children. While looking at different types of speakers, 80 adult male speakers between the ages of 40 and 80 yr., Ryan and Burk (1974) found that five voice characteristics, voice tremor, laryngeal tension, air loss, imprecise consonants, and slow rate of articulation, were strong predictors of perceived age. The first three of these relate directly to laryngeal physiology and there are clinical indications that subjects with Down's syndrome may have deviant vocal physiology. Benda (1969) reports high placement of
the larynx in the neck and myxedema of the cords. Clearly, additional studies of laryngeal and resonance physiology with these children are needed. Turning to perceptions of sex for the normal children and children with Down's syndrome the positive intrajudge Phi correlations were respectively .61 and .51. The mean correlation for actual sex versus judged sex for the normal children was .55. However, the average Phi for the biological sex of the subjects with Down's syndrome versus the judged sex was -.15. Thus, sexual identification of the Down's syndrome child through perceived voice may be exceedingly difficult and confirms the earlier hypothesis. The reported delayed and underdeveloped sexual development, even in prepubertal children with Down's syndrome, may in part account for the significant misidentification of these children by the judges. Some of the perceived deviant age and sex characteristics of the children with Down's syndrome voices may be related, at least in part, to conductive blocking found in their servo-mechanistic hearing feedback systems. Specifically, as reported earlier, these children had significantly elevated hearing thresholds of such a nature as to indicate possible mild conductive hearing impairments. It follows that these children having difficulty in monitoring their voices would have deviant vocal production. It seems possible that regular otological evaluations by otologists and treatment, when indicated, might assist in habilitating the perceptual vocal disorders found in children with Down's syndrome. REFERENCES BENDA,C. E. Down's syndrome. New York. Grune & Stratton, 1969. BLANCHARD,I. Speech pattern and etiology in mental retardation. American Journal o f Mental Deficiency, 1964, 68, 612-617. DELOACH,M. H . A study of the reliability of three hearing tests with institutionalized mongoloids. Unpublished master's thesis, Univer. of Florida, 1968. HOLLIEN,H., & COPELAND,R. Speaking fundamental frequency (SFF) characteristics of mongoloid girls. Journal of Speech and Hearing Disorders, 1965, 30, 344-349. MICHEL,J. F., & CARNEY,R. J. Pitch characteristics of mongoloid boys. Jourml of Speech and Hearing Disorders, 1964, 29, 121-125. MONTAGUE,J. C., BROWN, W. S., & HOLLIEN, H. Vocal fundamental frequenq characteristics of institutionalized mongoloids. American Journal of Mental Deficiency, 1974, 78, 414-418. MONTAGUE,J. C., & HOLLIEN,H. Perceived voice qualicy disorders in Down's syndrome children. Journal of Communicative Disorders, 1973, 6, 76-87. RYAN,W. J., & BURK,K. W. Perceptual and acoustic correlates of aging in the speech of males. Journal of Communicative Disorders, 1974, 7, 181-192. SHERMAN,D. The merits of backward playing of connected speech in the scaling of voice quality disorders. Journal of Speech and Hearing Disorders, 1954, 19, 312-321. WEINBERG, B., & ZLATIN,M. Speaking fundamental frequency characteristics of fiveand six-year old children with mongolism. Journal of Speech and Hearing Research, 1970, 13, 418-425. WINER, B. J. Statistical principlepin experimental design. New York: McGraw-Hill, 1971.
Accepted October 27, 1975.
PERCEIVED AGE A N D SEX CHARACTERISTICS OF VOICES OF INSTITUTIONALIZED CHILDREN W I T H DOWN'S SYNDROME JAMES C. MONTAGUE, JR.'
University of Arkansas at Little Rock Summary.-It was hypothesized that the voices of children with Down's syndrome would be perceived as younger than their true chronological age and that perceptual auditors would have considerable difficulty in identifying the correct sex of these children by voice alone. Perceived age and sex were investigated in 2 0 institutional children with Down's syndrome who were matched for sex and age with a control group of 2 0 normal children. Randomized matched verbal samples were played backwards to a group of 16 listener/judges who rated the samples as to age and sex. The results indicated that the voices of these Down syndrome children were perceived as being more than 2 yr. younger than their group mean age and that there was a negative correlation between the biological sex of such children and their perceived sex.
It has been reported (Blanchard, 1964; Benda, 1969) that children with Down's syndrome have deviant voices. To test these clinical impressions of vocal problems, a limiced number of objective acoustical and perceptual studies have been conducted in recent years. Generally speaking, the majority of the acoustical studies (Michel & Carney, 1964; Hollien & Copeland, 1965; Montague, Brown, & Hollien, 1974) showed the fundamental frequency for children with Down's syndrome to be essentially like those of normal children of the same CA. A somewhat different finding was reported by Weinberg and Zlatin (1970) who reported the speaking fundamental frequency levels of preschool children with Down's syndrome showed significantly higher speaking fundamental frequency than those of the matched sample of normals. However, the WeinberdZlatin sample with Down's syndrome was different from those in other studies, i.e., their subjects were controlled for specific genetic aberrations within Down's syndrome, were younger, and came from noninstitutionalired environments. Montague and Hollien (1973) objectively studied perceived voice quality deviations of 20 Down's syndrome and 20 normal control children. Their results showed chat children with Down's syndrome exhibited significantly more breathiness and roughness than did the normal group. More nasality was observed in the group with Down's syndrome than for normals, although che data were somewhat variable. To date, no studies have been conducted on the judgment of age and sex of children with Down's syndrome by voice alone. Deviant voices in children with Down's syndrome, with regard to perceived age and sex, might provide baseline data against which later biological or behavioral intervention strategies 'Address all correspondence to J. C. Montague, Jr., Speech and Hearing Clinic, Universiry of Arkansas at Little Rock, 33rd and University, Little Rock, Arkansas 72204.
216
J. C. MONTAGUE, JR.
might be measured. It has been well established (Benda, 1969) that these children are "unfinished children" with respect to the physical attributes of age and sex development by comparison with their normal peers. As a group such children ate shorter and smaller, and their sex organs are retarded in develop ment. Thus, it was hypothesized that the voices of Down's syndrome children would be perceived as being younger than their actual chronological age. It was further hypothesized that the listener/judges would have considerable difficulty in identifying the correct biological sex of the children with Down's syndrome by voice alone. METHOD Subjects One group was composed of 20 subjects medically diagnosed as Down's syndrome and selected from an institutional population; the control group contained 20 normal children selected from a local public school. The two groups were matched on the basis of sex and chronological age as well as chronological age within sex on an individual basis. Individuals in the retarded group had been institutionalized for an average of 6.27 yr., with a range from 7 mo. to over 12 yr.; their records showed an IQ range of from 17 to 58, with a mean IQ of 32.2. An additional independent variable of importance was hearing sensitivity. As noted in the hard-of-hearing and deaf, elevated heating thresholds may affect auditory self-monitoring and produce deviate vocal characteristics. A modified bilateral-ear choice technique, as developed by Kurtzrock (personal communication, Univer. of Florida, 1970), was utilized for auditory evaluations. The frequencies tested were 500, 1000, and 2000 Hz (ISO) ; Beltone portable audiometers, Models 12-A or 9-D, were utilized. The children with Down's syndrome were tested in a sound-treated room located in the Speech and Hearing Clinic on the institutional grounds. Hearing of the normal group of children was assessed in a quiet conference room in the school; slightly more ambient noise was noted during testing of the normal group. All 20 of the control subjects and 14 of the experimental subjects were reliably conditioned for hearing testing ( 6 children with Down's syndrome could not be conditioned, thus were not tested). The group with Down's syndrome had International Standards Organization mean hearing thresholds of 33.7 db at 500 Hz, 31.6 db at 1000 Hz, and 33.0 db at 2000 Hz. The pure tone threshold data for the control group was 19.7 db at 500 Hz, 8.2 db at 1000 Hz, and 4.0 db at 2000 Hz. As evident, the hearing thresholds of the children with Down's syndrome were somewhat higher than the normals. These hearing thresholds are similar to those reported by Deloach (1968) in her study of auditory acuity in mongoloids.
Voice Sampling Procedure It was judged essential that strictly matched verbal samples should be
CHARACTERISTICS OF VOICES AND DOWN'S SYNDROME
217
obtained from both groups. To accomplish this matching, a strategy was developed for eliciting identical single-word utterances from all subjects in both groups. Accordingly, 18 large black and white pictures of common subjects, such as "dog," "cat," "man," "woman," etc., were drawn and used as stimulus materials. The recordings of the subjects' responses were made in the same quiet environments used in the hearing testing. The examiner, sitting next to the subject, presented the stimulus picture while simultaneously saying the word; the subject so encouraged, responded verbally by repeating the appropriate word. After a brief training session, responses were obtained from the subjects for all 18 of the stimulus pictures. This combined visual/aural stimulus approach proved quite effective for eliciting the desired word samples from both groups of children. The verbal samples were recorded at 7.5 ips on an Ampex (Model 601 ) tape recorder coupled to an Electro-Voice (Model 664) microphone.
Analysis of Data The original tapes were dubbed and three words, "boy," "baby," and "doctor" were spliced from each subject's tape into a sequence with approximately 2-sec. pauses between them. A table of random numbers was used to order the 40 grouped responses from the 20 children with Down's syndrome and 20 control subjects; a second randomization of these 40 stimuli was added to the first. Following each of the 80 three-word sets, a 4- to 6-sec. pause was placed on the tape to allow sufficient time for the judges to make their perceptual decisions. Of concern was the possibility that other verbal components (besides age and sex characteristics) might influence the ratings. Specifically, the probability existed that the subjects with Down's syndrome would exhibit defective speech (misarticulation and the like) and thus influence the judges' ratings. To control this possible bias, all samples were played backward (see Sherman, 1959). Finally, to eliminate perceptual cues from identifiable noise on the tapes, all taped samples were processed through an 18-db per octave filter bandpass of 150 to 4000 Hz.
Judging Procedure Judges were 16 paid undergraduate students. The listening session was conducted in an acoustically treated classroom in the Communication Sciences Laboratory at the University of Florida. The stimuli were presented via a Model 602-1 Ampex recorder with an associated Model 622 Amplifier/speaker system. Prior to the listening session, a speech-discrimination test (CID Auditory Test-22) was administered to all listeners; no volunteers failed this test. At the initiation of the listening task, the judges were told that they would be listening to a series of children's voices and were asked to make judgments relative to each child's sex and age. On the judges' sheets, for each of the 80 sets of stimuli, were dichotomou~male/female choice blanks and eight scaled age-choices; running from age 6 to 13. The judges listened to the entire 80
2 18
J. C.
MONTAGUE, JR.
sets of stimuli making their male/female judgments and then listened to the tape again to make their final perceived age choices. The entire rating procedure took less than 1 hr. At no time were the listeners given any suggestion that many of the samples they were listening to belonged to children with Down's syndrome. RESULTSAND DISCUSSION An analysis of variance, utilizing a correlation derivation (Winer, 1971), was used for computing the intrajudge reliability on the age ratings for the 16 listener/judges in comparing their first versus last sets of 40 ratings. Positive intrajudge correlations of .64 and .67 were computed respectively for the normal and Down's syndrome children. While only moderate, these positive correlations suggest that there was reasonable agreement within each judge's auditory perceptual judgments of the ages of normal and retarded children. Interjudge reliabilities of the age ratings were also positive, with .55 reported for the normal group of children and .82 for the children with Down's syndrome. It is interesting to note that among themselves the listener/judges apparently were more in agreement with respect to the ratings of age of children wich Down's syndrome than of the normal children. The mean rating of age for the normal children was 10.45 yr., with an S D of 1.78, whereas the children with Down's syndrome were rated 8.17 yr., wich an SD of 1.81. The mean age of the normals, 10.45 yr., coincided with their actual mean age CA of 10.41 yr. reported in Table 1. However, the children TABLE 1 SEX, MEAN, AND RANGE OF CHRONOLOGICAL AGE FOR Group Male Down's Syndrome Control
10 10
Sex Female 10 10
M 10.42 10.41
-0
GROUPS
Chronological Age Range 7.75 to 13.50 8.00 to 13.25
with Down's syndrome were perceived as being approximately 2.25 yr. younger. This appears to confirm the hypothesis that the voice of the child with Down's syndrome is perceived to a large degree as being below his/her chronological age. This may be attributed to one or more deviant physiological parameters unique to this group of retarded children. While looking at different types of speakers, 80 adult male speakers between the ages of 40 and 80 yr., Ryan and Burk (1974) found that five voice characteristics, voice tremor, laryngeal tension, air loss, imprecise consonants, and slow rate of articulation, were strong predictors of perceived age. The first three of these relate directly to laryngeal physiology and there are clinical indications that subjects with Down's syndrome may have deviant vocal physiology. Benda (1969) reports high placement of
the larynx in the neck and myxedema of the cords. Clearly, additional studies of laryngeal and resonance physiology with these children are needed. Turning to perceptions of sex for the normal children and children with Down's syndrome the positive intrajudge Phi correlations were respectively .61 and .51. The mean correlation for actual sex versus judged sex for the normal children was .55. However, the average Phi for the biological sex of the subjects with Down's syndrome versus the judged sex was -.15. Thus, sexual identification of the Down's syndrome child through perceived voice may be exceedingly difficult and confirms the earlier hypothesis. The reported delayed and underdeveloped sexual development, even in prepubertal children with Down's syndrome, may in part account for the significant misidentification of these children by the judges. Some of the perceived deviant age and sex characteristics of the children with Down's syndrome voices may be related, at least in part, to conductive blocking found in their servo-mechanistic hearing feedback systems. Specifically, as reported earlier, these children had significantly elevated hearing thresholds of such a nature as to indicate possible mild conductive hearing impairments. It follows that these children having difficulty in monitoring their voices would have deviant vocal production. It seems possible that regular otological evaluations by otologists and treatment, when indicated, might assist in habilitating the perceptual vocal disorders found in children with Down's syndrome. REFERENCES BENDA,C. E. Down's syndrome. New York. Grune & Stratton, 1969. BLANCHARD,I. Speech pattern and etiology in mental retardation. American Journal o f Mental Deficiency, 1964, 68, 612-617. DELOACH,M. H . A study of the reliability of three hearing tests with institutionalized mongoloids. Unpublished master's thesis, Univer. of Florida, 1968. HOLLIEN,H., & COPELAND,R. Speaking fundamental frequency (SFF) characteristics of mongoloid girls. Journal of Speech and Hearing Disorders, 1965, 30, 344-349. MICHEL,J. F., & CARNEY,R. J. Pitch characteristics of mongoloid boys. Jourml of Speech and Hearing Disorders, 1964, 29, 121-125. MONTAGUE,J. C., BROWN, W. S., & HOLLIEN, H. Vocal fundamental frequenq characteristics of institutionalized mongoloids. American Journal of Mental Deficiency, 1974, 78, 414-418. MONTAGUE,J. C., & HOLLIEN,H. Perceived voice qualicy disorders in Down's syndrome children. Journal of Communicative Disorders, 1973, 6, 76-87. RYAN,W. J., & BURK,K. W. Perceptual and acoustic correlates of aging in the speech of males. Journal of Communicative Disorders, 1974, 7, 181-192. SHERMAN,D. The merits of backward playing of connected speech in the scaling of voice quality disorders. Journal of Speech and Hearing Disorders, 1954, 19, 312-321. WEINBERG, B., & ZLATIN,M. Speaking fundamental frequency characteristics of fiveand six-year old children with mongolism. Journal of Speech and Hearing Research, 1970, 13, 418-425. WINER, B. J. Statistical principlepin experimental design. New York: McGraw-Hill, 1971.
Accepted October 27, 1975.
