Dysphonia and Dysarthria in People With Parkinson's Disease After Subthalamic Nucleus Deep Brain Stimulation: Effect of Frequency Modulation.

PURPOSE: Subthalamic nucleus deep brain stimulation (STN-DBS) parameters, for example the frequency of stimulation, seem to affect speech and voice aspects. However, this influence is not well understood. This study aimed to investigate the impact of low- and high-frequency STN-DBS on voice and speech for people with Parkinson's disease.

METHODS

Nineteen individuals with Parkinson's disease who received bilateral STN-DBS were assessed for motor performance (Unified Parkinson's Disease Rating Scale-III), perceptual evaluation of voice (grade, roughness, breathiness, asthenia, strain, and instability [GRBASI]), dysarthria assessment, and computerized acoustic analysis of voice upon receiving low-frequency (60 Hz) and high-frequency (130 Hz) STN-DBS.

RESULTS

In the GRBASI protocol, asthenia, and instability were significantly better at 130 Hz of stimulation. In the dysarthria evaluation, the phonation aspect, articulation, and grade of dysarthria showed deterioration at the same high-frequency condition. There was no significant difference for any vocal acoustic measures.

CONCLUSION

The high-frequency of STN-DBS may affect speech and voice differently, leading to an amelioration of the vocal production, but with adverse effects in the speech control.