Effects of deep brain stimulation on spontaneous language production in people with Parkinson’s disease: a preliminary study
The effects of bilateral subthalamic nucleus (STN) stimulation on spontaneous language production are poorly understood. Using a pre-post surgery design, semantic and morphosyntactic parameters were evaluated according to the “Analysis of Spontaneous Speech in Aphasia” in seven people with Parkinson’s disease (PD). Relative to normative data, the number of nouns and percentage of correct sentences produced were most subjective to changes over time and effects of stimulation. Twelve months after surgery, three patients with predominant left hemispheric dopamine depletion showed a normalization of the number of nouns during STN stimulation, compared to results below the norm in the bilateral OFF condition. Moreover, the effect on the percentage of correct sentences was variable, but the results remained below the norm when preoperative deficits were present. These outcomes suggest that motor symptom laterality and preoperative language functioning are among the variables that mediate STN stimulation effects on spontaneous language production, and emphasize the relevance to include the number of nouns and percentage of correct sentences produced as parameters in future larger-scale research.
Cocquyt, E.M., Rofes, A., Batens, K., Miatton, M., Raedt, R., Duyck, W., De Letter, M., Van Roost, D., Santens, P. (2026). Effects of deep brain stimulation on spontaneous language production in people with Parkinson’s disease: a preliminary study. Journal of Neurolinguistics. Impact Factor: 1.2. Ranking Q2. PDF available here
