Amyloid plaque burden and dual tasking impairments on the Timed up and go test in Parkinson disease (P5-11.006)

Abstract

<h3>Objective:</h3> Dual tasking (DT) impairments in Parkinson disease (PD) are a correlate of fall risk. Their biological basis may reflect multiple underlying pathological causes. <h3>Background:</h3> Low-level amyloid-beta (Abeta) plaque burden is known to correlate with gait and cognitive impairments in PD. It is possible that Abeta plaque burden may exacerbate fall risk by worsening dual tasking cost, though this has not been evaluated to date. <h3>Design/Methods:</h3> In a cross-sectional cohort of 20 participants with PD, we explored the association between Abeta plaque burden and dual task cost (DTC) on the timed up and go test (TUG). TUG gait parameters were assessed using Ambulatory Parkinson’s disease monitoring (APDM) OPAL wearable sensors. Baseline TUG testing was followed by TUG testing during which the participant performed a cognitive task. DTC was calculated as the percentage difference in seconds between the two tasks. Regional Abeta plaque burden was assessed by [11C]Pittsburgh compound B (PiB) positron emission tomography (PET) imaging. Bivariate Pearson’s r statistic was calculated between DTC and PiB distribution volume ratio (DVR) in different regions of interest. <h3>Results:</h3> DTC during the TUG show no significant correlations with PiB DVR in the total cortical mantle (r=0.061, p=0.797), visuospatial cortex (r=0.061, p=0.798), striatum (r=0.033, p=0.890), or thalamus (r=0.041, p=0.865) but did correlate with elevated PiB DVR in the substantia nigra (r=0.535, p=0.015). <h3>Conclusions:</h3> DTC in PD does not correlate with supratentorial amyloid plaque burden but may reflect mixed neurodegenerative pathology, including Abeta plaque burden, in the substantia nigra. <b>Disclosure:</b> Ms. Harrie has nothing to disclose. The institution of Dr. Hampstead has received research support from NIH. The institution of Dr. Hampstead has received research support from Department of Veterans Affairs. Dr. Hampstead has received intellectual property interests from a discovery or technology relating to health care. Dr. Hampstead has received publishing royalties from a publication relating to health care. Catherine Lewis has nothing to disclose. Ms. Herreshoff has received personal compensation in the range of $50,000-$99,999 for serving as a Consultant for Huxley Medical Inc. Dr. Kotagal has received personal compensation in the range of $500-$4,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Movement Disorders Society. The institution of Dr. Kotagal has received research support from NIH. The institution of Dr. Kotagal has received research support from VA Healthcare System.