Voice target time in Parkinson's disease: A preliminary report

A target-matching paradigm was developed to assess the vocal equivalents of reaction and movement time in Parkinson's disease. Six patients with Parkinson's disease and 6 age- and gender-matched control subjects were asked to enunciate /pa/ to reach a target frequency and intensity level in response to a light stimulus. The stimulus and acoustic responses were simultaneously recorded. Measures included laryngeal reaction time, time between stimulus and phonation onset; frequency voice target time, time from phonation onset to target level of frequency; and amplitude voice target time, time from phonation onset to target level of intensity. The 2 subject groups were significantly differentiated by laryngeal reaction time (t = 299.67, df = 10, P = 0.005) and frequency voice target time (t = 148, df = 10, P = 0.014). These data suggest voice target time is a viable tool for assessing the effects of neurologic disorders on voice execution in Parkinson's disease.