Acoustic and Auditory-Perceptual Characteristics of Korean Stop Consonants in Patients with Idiopathic Parkinson’s Disease and Cerebellar-Multiple System Atrophy

Abstract

Objectives: This study aims to investigate Korean stop consonant production in patients with idiopathic Parkinson’s disease (IPD) and Multiple System Atrophy-cerebellar variant (MSA-C) in aiding in differentiating the two types of diseases with Parkinsonism in common. Method: We included a total of 30 subjects (M:F=15:15) (10 with IPD, 10 with MSA-C, 10 age-matched normals). The subjects were to produce nine Korean stops, /p/, /p’/, /ph/, /t/, /t’/, /th/, /k/, /k’/, /kh/ embedded in VCV contexts. The speech data were analyzed with the Praat program, and the analyses included length and ratio of closure sections and aspiration sections; speech rate, variability across repeated measurements; and error patterns based on auditory-perceptual evaluation. Results: The MSA-C group demonstrated a significantly longer duration than IPD and normal control groups in closure and aspiration sections in seven and two consonants, respectively. Within the combined closure and aspiration sections, the IPD group showed a significantly higher aspiration duration ratio for all the aspirated consonants /ph/, /th/, /kh/ than MSA-C and normal control groups. The MSA-C group frequently manifested substitution errors of lax consonants with tense or aspirated consonants. The IPD group substituted dental plosives with velar plosives. Conclusion: Difficulty in coordinating between the laryngeal and articulatory gestures in MSA-C and IPD groups is differentially manifested in absolute and relative measures of duration of closure and aspiration segments in stop consonants. In addition, the reduced laryngeal-articulatory movements appeared auditory-perceptually as erroneous substitutions of lax consonants with tense or aspirated consonants. Further studies are warranted to investigate more diverse severities of patients with high volume recruitment.