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

Abstract

Background/Aims: 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). Conclusion: These findings may indicate the validity of nonlinear dynamic analysis as a complement to perceptual analysis in clinical PD voice studies.

Acoustic Voice Modifications in Individuals with Parkinson Disease Submitted to Deep Brain Stimulation

“…It is important to note that different methodological approaches have been used to investigate the voice in this population in terms of DBS condition (pre and postsurgery, on- and off-DBS stimulation) and voice assessment tools (subjective assessment of perpetual and psychosocial aspects, objective assessment using acoustic analysis or aerodynamic measures). 14 16 17 18 19 20 21 22 We consider that the investigations of on and off DBS conditions is the best choice to evaluate the effects of the stimulation per se, since the investigation of pre and postsurgery conditions is biased by the effects of the surgical procedure, such as possible brain lesions caused by the surgery. Furthermore, different voice assessment methods also provide different information.…”

Parâmetros acústicos e perceptivo-auditivos da voz de adultos e idosos

“…F0=frequência fundamental, dp=desvio padrão, NHR=proporção ruído-harmônico VTI=índice de turbulência vocal, SPI=índice de fonação suave Tabela 10 -Correlação entre os parâmetros acústicos e perceptivo-auditivos da voz de mulheres FLETCHER, 2008;ZHOU et al, 2009;BAUDONCK et al, 2011)…”