Perception of Musical Rhythm in Persons with Stuttering

Abstract

Suprasegmental features of a language are those properties of speech sounds that appear simultaneously with the phonetic features but are not confined to phonetic segments and instead are overlaid or superimposed on syllables, words, phrases and sentences. Although much information in speech is conveyed by the segmental phonemes, additional information is carried by the prosodic features. It includes intonation, stress, rhythm, and juncture (pause) or phrasing. Stuttering is considered to be a disorder of rhythm and is attributed to lack of or reversal of cerebral dominance. If stuttering is attributed to lack of cerebral dominance, the ear preference in stutterers would be different when compared to normal individuals. In this context the present study investigated the perception of musical rhythm and ear preference in persons with stuttering. Two groups of subjects participated in the experiment. Group I consisted of 10 persons with stuttering (PWS) and group II consisted of 10 adult non musician normals in the age range of 18-30 years. The rhythm structures selected were four ta:las, from Catusra, Tisra, Misra and Khanda. The subjects were presented with the talas in monaural condition and in dichotic condition. The results indicated no significant ear or group differences under monotic presentation. However in PWS, left ear preference was observed and in normals right ear preference was observed. Misra ta:la was the most difficult and Tisra and Khanda ta:las were the easiest to identify. Under dichotic presentation varying responses were observed. In general, it was observed that compared to normals PWS were poorer in identifying rhythm. In normals a wide difference was observed between the identification scores of ears, while in PWS it was not so. This probably indicates mixed laterality in PWS. Tisra ta:la was not preferred except when it was presented in right ear along with Misra ta:la in left ear. Also, whenever Khanda and Misra ta:las were presented dichotically, there was a confusion and no ta:la was identified. The results indicated that the identification of rhythm was different in PWS compared to normals and that there was a right hemisphere dominance or mixed laterality in PWS.