Acoustic Analysis of Vowel Sound in Children with Spastic Cerebral Palsy

ABSTRACT

OBJECTIVE: To investigate the acoustic characteristics of the vowel phonation in children with spastic cerebral palsy (CP) and normal children METHOD: Twenty-six children with spastic diplegic CP and seventeen normally developed children were recruited as subjects. Voice samples were collected by pronouncing at full length /a/, /i/, and /u/ three times each into a microphone. With these samples, maximum phonation time using Multi-speech model 3,700, fundamental frequency, jitter percent, shimmer percent, noise to harmony ratio using Multi-Dimensional Voice Program model 5105, and 1st formant, 2nd formant using PraatTM were measured. RESULTS: Maximum phonation time was significantly shorterin the CP group than normal group (p<0.05). Jitter percent and Shimmer percent were significantly increased in the CP group than in the normal group (p<0.05). Fundamental frequency, 1st formant and 2nd formant were not significantly different between the two groups. CONCLUSION: Relatively short duration of maximum phonation time in the CP group suggests poor respiratory control and capacity in children with CP. Higher level of shimmer percent in CP group indicates instability of voice quality that result from poor laryngeal function. No significant difference in 1st formant and 2nd formant between the CP and control group suggests similar vowel articulatory ability.