P.003 Structural integrity of the nucleus basalis of meynert in Parkinson’s Disease related cognitive and gait decline

Background: In Parkinson’s disease (PD), mounting evidence implicates degeneration of cholinergic systems in cognitive and gait decline. The Nucleus Basalis of Meynert (NBM) is a major cholinergic nucleus with widespread cortical projections. We hypothesized that atrophy of the NBM is correlated with cognitive phenotypes and gait measures in PD. Methods: Subjects from the COMPASS-ND study (20 controls and 79 PD patients) were studied. Clinical measures included cognitive diagnosis (MCI, dementia) and quantitative gait parameters with dual task gait. Manual region of interest measurement of the NBM was performed on T1 MRI scans. NBM volumes were analyzed against clinical measures. Results: PD-MCI and PD-dementia patients had greater dual task costs to gait speed when performing serial 7s (mean difference -12%, p=0.02; -11%, p=0.04) and animal fluency tasks (mean difference -9%, p=0.02; -15%, p