Stimulation of the Thalamus to Ameliorate Parkinsonian Speech Disfluencies: Pilot Study

Purpose: The purpose is to assess if dominant thalamic Deep Brain Stimulation (DBS) is an effective treatment for Parkinsonian stutter. Functional magnetic resonance imaging (MRI) will detect brain dominance before surgery. The research team will assess whether dominant thalamic DBS is preferable for stutter treatment.

Hypothesis: The research team hypothesizes that dominant thalamic neuromodulation with DBS effectively treats PD stutter.

Justification:

The investigators initially began investigating the possibility of treatment of Stutter with DBS when they had a patient whose stutter serendipitously improved following thalamic DBS for tremor. The patient had severe tremor requiring bilateral thalamic DBS; he coincidentally had stutter. Post-operatively, the patient noted that he had had marked improvement in his tremor as well as his stutter. This prompted a literature search, where the investigators found that this has previously been reported in one other patient. Previous investigations of spasmodic dysphonia show that speech (similar to language) is lateralized in most patients, and that unilateral treatment of the dominant hemisphere is as beneficial as bilateral treatment.

Objectives: The objective is to perform a case series of three patients to assess feasibility and determine design of a future, larger study. If there is an appreciable reduction in stuttering with dominant stimulation, a larger unilateral (dominant) thalamic study can be undertaken. The magnitude of effect determined by this pilot trial will allow for a power calculation for the future study.