Production ability for Korean bilabial stops in Parkinson's disease

Abstract

The aim of this study was to find out the acoustic characteristics of bilabial stops that are needed for the coordination of larynx and supra-larynx in Parkinson's disease (PD) speakers. Nine Korean C_{bilabial-stops}VC (where C is a consonant and V a vowel) syllables were used by including V-C_stopsVC sequence in the frame /” “i “”ilakomalhanta/ ( “”says “”). Target syllables, C_stopsVC, were /pal/, /p^*al/, /p^hal/, /pul/, /p^*ul/, /p^hul/, /pin/, /p^*in/ and /p^hin/. Closure and aspiration durations were measured in nine PD speakers and eight normal speakers. The ratio of closure duration of all stops was then computed. The results revealed that PD speakers lack coordination of the larynx and supra-laryngeal movements as compared to normal speakers. However, the PD speakers were able to maintain the relative production ability needed to differentiate three types of stops; /p/, /p^*/ and /p^h/. These results support the view that temporal coordination deficits of the larynx and supra-laryngeal movements are part of the speech production disorders of PD speakers.

• Closure duration
• aspiration duration
• Parkinson's disease
• Korean stops
• temporal coordination