The effect of pallidal stimulation on sleep outcomes and related brain connectometries in Parkinson's disease.

Sleep difficulties affect up to 98% of Parkinson's disease (PD) patients and are often not well treated. How globus pallidus internus (GPi)-DBS could help is less understood. We retrospectively analyzed sleep outcomes in 32 PD patients after GPi-DBS with a two-year follow-up. We observed high heterogeneity in sleep response to pallidal stimulation: 16 patients showed clinically meaningful improvement, 9 had minor changes, and 7 experienced worsened sleep quality, with no overall significant change on the Parkinson's Disease Sleep Scale-2 (P = 0.19). Further analysis revealed that stimulation of the left sensorimotor GPi was significantly associated with sleep improvement. Fiber tracts from the left sensorimotor GPi to the bilateral sensorimotor cortex, right GPi, brainstem, and bilateral cerebellum were linked to better sleep, while projections to the left hippocampus correlated with worsened sleep. These findings may guide personalized GPi-DBS lead placement to optimize sleep outcomes in PD.