Spastic Diplegia ; Cerebral Palsy ; maximum phonation time ; fundamental frequency ; jitter ; shimmer ; noise to harmonic ratio ; formant
Abstract
This study reports an investigation on the acoustic characteristics in the vowel phonation of preschool children with spastic diplegia due to cerebral palsy(CP). A group of 15 children with spastic diplegia were compared to 9 normal controls in sustained /a/ phonation. There were significant differences between the two groups in the maximum phonation time, jitter percent, shimmer percent, and noise to harmonic ratio. The respiratory capacity of the CP children was reduced and phonation capacity was also impaired due to the defect in vocal cord control. Maximum phonation time of the CP children did not increase as age increased whereas that of the normal controls did. When average fundamental frequency, first formant, and second formant of vowel were compared between the two groups, no reliable difference was found. The results indicate that unlike other types of CP, spastic diplegia children with better upper body control have a similar ability to normal developing children in vowel articulatory ability compared to respiration and phonation.