P.097 Effect of stimulation site on brain network activity and phonemic verbal fluency: an fMRI study.

Background: In Parkinson’s disease, deep brain stimulation (DBS) of the subthalamic nucleus (STN) or globus pallidus internus (GPi) produces comparable motor benefits. Although both increases risk cognition and verbal fluency (VF) decline, is greater following STN-DBS. The consequences stimulating these different sites on network activity unknown. We use functional magnetic resonance imaging (fMRI) during in vivo to investigate differences between STN-DBS GPi-DBS correlate with change VF. Methods: Left-sided, stimulation-cycling block-design fMRI was acquired at 3-Tesla 51 15 routine clinical programming. Blood oxygen level-dependent (BOLD) response compared groups. Phonemic VF assessed pre- postoperatively. Results: Voxel-wise t-test BOLD maps revealed areas significant difference (p<0.001) left frontal operculum caudate head. Stimulation appears show slight inverse correlation postoperative decline. trend reversed GPi-DBS. Conclusions: Decline PD-DBS seems associated effect differs depending site, suggesting differing effects activity.