Evaluation of the effects of deep brain stimulation of the subthalamic nucleus and levodopa treatment on parkinsonian voice using perturbation, nonlinear dynamic, and perceptual analysis.
OBJECTIVE
To quantify aperiodic phonation, nonlinear dynamic methods of acoustic voice analysis, such as correlation dimension, have been shown to be useful. The purpose of this study is to evaluate the validity of nonlinear dynamic analysis as a voice analysis tool for the effects of deep brain stimulation (DBS) and levodopa on patients with Parkinson's disease (PD).


METHODS
In this study, the effects of DBS and levodopa treatment on patients with PD were measured using perturbation, nonlinear dynamic, and perceptual analysis. Nineteen PD patients that received bilateral (n = 9), left (n = 7), or right (n = 3) DBS performed sustained vowel phonations, which were recorded before and after medication with the stimulator off and on. Recordings were also taken of 10 PD patients who did not receive DBS surgery before and after medication to provide a baseline.


RESULTS
A mixed two-way ANOVA (surgery, medication) generated significant positive treatment effects of DBS only in mean log-transformed D2, which was supported by mean log-transformed shimmer, vF0 (variability in fundamental frequency), and vAm (peak-to-peak amplitude variation).


CONCLUSIONS
These findings may indicate the validity of nonlinear dynamic analysis as a complement to perceptual analysis in clinical PD voice studies.
Zhou
Xiao Ping
XP
Department of Neurosurgery, Shanghai Second Military Medical University, Shanghai, China.
Lee
Victoria S
VS
Wang
Emily Q
EQ
Jiang
Jack J
JJ
D000368:Aged; D000978:Antiparkinson Agents / Q000627:therapeutic use*; D046690:Deep Brain Stimulation; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D017711:Nonlinear Dynamics; D020734:Parkinsonian Disorders / Q000188:drug therapy / Q000601:surgery / Q000628:therapy*; D010699:Phonation / Q000187:drug effects; D010700:Phonetics; D013068:Speech Production Measurement; D020531:Subthalamic Nucleus / Q000601:surgery; D016896:Treatment Outcome; D014831:Voice / Q000187:drug effects; D014832:Voice Disorders / Q000188:drug therapy / Q000601:surgery / Q000628:therapy*
D000978:Antiparkinson Agents; D007980:Levodopa