VOICE ONSET TIME OF OCCLUSIVE CONSONANTS PRODUCED BY SPANISH-SPEAKING PARKINSON PATIENTS

Abstract

This study is situated in the field of Clinical Phonetics and aimed at determining Voice Onset Time (VOT) measures in the voiced and voiceless occlusive sounds of Spanish native speakers with Parkinson’s disease and comparing them with those from a control group. To that end, data were taken from seventeen people with Parkinson’s disease (seven women, ten men) and seventeen control participants, with both groups matched for age and gender. The participants read words and pseudowords that contained the consonants /p/, /t/, /k/, /b/, /d/ and /g/ in word-initial position, either preceded or not by the particle/article /un/ (preceding context variable) recommended by Roldán and Soto (1997). VOT measures in the voiced and voiceless occlusive consonants were calculated with the Praat computer software and analyzed using descriptive statistics, Shapiro-Wilk tests, and median comparison tests of Wilcoxon for independent samples. The results indicate that VOT in the voiceless occlusive consonants for the group with Parkinson’s disease is longer than for the control group. Additionally, the results show a statistically significant effect for the VOT values with or without the use of the particle /un/. This study constitutes one of the first research papers analyzing the VOT of persons with Parkinson’s disease in Colombia, and it suggests future challenges in the acoustic analysis of the atypical speech of the Spanish-speaking population.