Relief of acquired stuttering associated with Parkinson's disease by unilateral left subthalamic brain stimulation

In this article, the authors report a case of acquired stuttering associated with Parkinson's disease (PD) that was responsive to unilateral subthalamic nucleus deep-brain stimulation (STN DBS) in the language-dominant hemisphere.

A single-subject, masked, multiple baseline design was used to evaluate the effects of unilateral left STN DBS on stuttering associated with PD. The patient underwent 3 formal speech assessments of spontaneous speech and the reading of passages with DBS off and on. Speech samples were videotaped and placed in random order, and 2 independent speech-language pathologists calculated the percentage of stuttered syllables and classified individual stuttering events.

Stuttering improved significantly in the DBS-on condition. In total, 10% of syllables were affected by stuttering events with DBS off, and less than 1% of syllables were affected by stuttering events with DBS on (n = 2,281 syllables, p < .00001, in a chi(2) test). The effect of unilateral STN DBS on stuttering was relatively independent of whether the patient was on or off dopaminergic medications.

This article emphasizes the important role of the subthalamic region in the motor control of speech and language.