The relationship between degree of disability and vocal range, vocal range midpoint, and pitch-matching ability of mentally retarded and psychiatric clients
Abstract: The purpose of this study was to investigate the relationship between degree of disability and vocal range, vocal range midpoint, and pitch-matching ability of mentally retarded and psychiatric clients. Subjects included 35 male and female mentally retarded vocational rehabilitation clients and 55 male psychiatric patients. The procedure included recording the vocalizations of subjects upward and downward by semi-tones to obtain vocal range and vocal range midpoint. Pitch-matching ability was determined by asking each subject to sing four predetermined pitches. For mentally retarded subjects, degree of disability was determined by IQ scores. For psychiatric patients, disability was determined by ratings of two professional staff members. Multiple regression and simple correlation analyses were carried out seperately for the psychiatric and mentally retarded samples to determine if degree of disability could be predicted from age, vocal range, vacal range midpoint, and pitch-matching ability. Independent t-tests were used to determine differences in the dependent variables between the groups. Results for the mentally retarded sample indicated a significant relationship between degree of diability (IQ level) and age, vocal range, and pitch-matching ability (p < .02). Simple correlations indicated that, as ages of subjects increased, IQ levels decreased (p < .05). Significant correlations were found between the variables of vocal range and pitch-matching ability (p < .01), vocal range and vocal range midpoint (p < .01), and vocal range midpoint and pitch-matching ability (p < .01). No significant results were obtained for the psychiatric sample.
Note: vocal-range-midpoint, pitch-matching-ability.
Keyword(s): disabilities, developmental-disabilities, mental-retardation, psychiatric, vocal-range, pitch.