Neuropsychological and psychiatric outcome of GPi-deep brain stimulation in dystonia

Previous investigators have observed changes in cognitive and psychiatric domains after GPi-DBS for dystonia, such as declines in semantic verbal fluency and set shifting or increased suicidality. Others have reported stability or improvements in select areas, such as graphomotor speed and mood. Interpretation of these findings is limited by inclusion of select patient populations or limited neuropsychological testing.

To describe cognitive and neuropsychiatric outcomes in a cohort of patients with primary and secondary dystonia undergoing Globus Pallidus pars interna deep brain stimulation (GPi-DBS).

Patients with primary and secondary dystonia were evaluated at baseline and post-operatively with a comprehensive battery of neuropsychological tests and mood inventories including anxiety, depression and hopelessness scales. Statistical significance was calculated with one-tailed student t-test, defined as p value < 0.05.

Twelve patients were included in the study. Nine were male (75%) and the mean age at baseline assessment was 42.3 years (range 13-68; SD 18.0). The majority had focal or segmental dystonia (8/12, 66%), 4 patients had generalized dystonia. Three patients had monogenic dystonias (DYT 1 and DYT 3), and two patients had acquired (tardive) dystonia. Mean time between surgery and follow-up was 13.1 months (SD 3.1). Subjects demonstrated stable performance on most tests, with statistically significant improvements noted in working memory (letter-number sequencing), executive function (trail-making B), anxiety and depression.

In an etiologically and clinically diverse patient population, administration of comprehensive battery of cognitive tests pre and post-operatively suggests that GPi-DBS is safe from cognitive and psychiatric perspectives.