Deficits in fine motor coordination in children with unintelligible speech

An auditory and acoustic analysis was performed of the voice production of 24 children between 5 and 8 years of age with unintelligible speech and 24 children without speech or language deficits matched for age. Two aspects of voice production were assessed, prephonatory tuning and phonatory modulation. The categories used for the auditory assessment were preutterance vocalizations, abnormal initiation, rough voice, breathy voice, tense voice, voice tremor, intraphonemic disruption and pitch break. The acoustic analysis consisted of calculation of the mean fundamental frequency and the pitch perturbation factor in repetitions of the series of syllables /pa/, /ta/, /ka/. Intrasyllabic pitch breaks were also noted. The children with unintelligible speech had significantly more signs of abnormal prephonatory tuning and abnormal phonatory modulation than the control children. The findings suggest that voice production in unintelligible children has not yet become automatized. This possibility is discussed in relation to the central control of phonation.