Nucleus Basalis of Meynert Stimulation for Lewy Body Dementia: A Phase I Randomized Clinical Trial

OBJECTIVES:Nucleus basalis of Meynert deep brain stimulation (NBM-DBS) has been proposed for patients with dementia. Here, we aim to assess the safety and effects of NBM-DBS in patients with Lewy-body dementia (LBD), in a randomized, double-blind and crossover clinical trial. METHODS:Six patients with mild to moderate LBD (mean [SD] age, 62.2 [7.8] years) were included and operated for bilateral NBM-DBS, and assigned to receive either active or sham NBM-DBS, followed by the opposite condition for 3 months. The primary outcome was the difference in the total free recalls of the Free and Cued Selective Reminding Test (FCSRT) between active versus sham NBM-DBS. Secondary outcomes were assessments of the safety and effects of NBM-DBS on cognition, motor disability, sleep and PET imaging. RESULTS:There was no significant difference in the FCSRT with active versus sham NBM-DBS. The surgical procedures were well tolerated in all patients, but we observed significant decreases in Stroop and Benton scores after electrode implantation. We observed no significant difference in other scales between active versus sham NBM-DBS. With active NBM-DBS relative to baseline, phonemic fluency and motor disability significantly decreased. Lastly, the superior lingual gyrus metabolic activity significantly increased with active NBM-DBS. CONCLUSIONS:NBM-DBS does not appear to be totally safe for LBD patients with no evidence of cognitive benefit. CLASSIFICATION OF EVIDENCE:This study provides Class II evidence that for patients with LBD operated for bilateral NBM-DBS, active NBM-DBS stimulation compared to sham stimulation did not significantly change selective recall scores.