Effect of bilateral stimulation of the subthalamic nucleus on parkinsonian dysarthria
Gentil, M., Pinto, S., Pollack, P., & Benabid, A. (2003) Effect of bilateral stimulation of the subthalamic nucleus on parkinsonian dysarthria , Vol 85(2), 190-196
This study examined speech production in 16 PD patients on and off bilateral DBS-STN stimulation. The patients’ speech was moderately impaired when assessed without medication and without stimulation. Speech production was quantitatively assessed by measuring the force of the lips and tongue and the acoustic features (i.e., duration, vocal vibration, intensity) of vocal expression. The results showed that on stimulation, patients showed a large increase in maximal force of the lips and tongue. In addition, a reduction in speech pauses and an increase in phonemic length was observed during stimulation. These results suggest some improvement in the motoric (related to the muscles influential in speech) and acoustic components of speech during stimulation, but the authors note that the results are not applicable to patients with more severe speech disorders.