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Lookup NU author(s): Dr Rachael Lawson,
Dr Gordon Duncan,
Dr Tien Kheng Khoo,
Professor Lynn Rochester,
Professor David Burn,
Dr Alison Yarnall
This is the authors' accepted manuscript of an article that has been published in its final definitive form by IOS Press, 2021.
For re-use rights please refer to the publisher's terms and conditions.
Background Cognitive impairment is common in Parkinson’s disease (PD), with 80% cumulatively developing dementia (PDD). We sought to identify tests that are sensitive to change over time above normal ageing so as to refine the neuropsychological tests predictive of PDD. Methods Participants with newly diagnosed PD (n=211) and age-matched controls (n=99) completed a range of clinical and neuropsychological tests as part of the ICICLE-PD study at 18-month intervals over 72 months. Impairments on tests were determined using control means (<1-2SD) and median scores. Mild cognitive impairment (PD-MCI) was classified using 1-2SD below normative values. Linear mixed effects modelling assessed cognitive decline, while Cox regression identified baseline predictors of PDD. Results At 72 months, 46 (cumulative probability 33.9%) participants had developed PDD; these participants declined at a faster rate in tests of global cognition, verbal fluency, memory and attention (p<0.05) compared to those who remained dementia-free. Impaired baseline global cognition, visual memory and attention using median cut-offs were the best predictors of early PDD (area under the curve [AUC]=0.88, p<0.001) compared to control-generated cut-offs (AUC=0.76-0.84, p<0.001) and PD-MCI (AUC]=0.64-0.81, p<0.001). Impaired global cognition and semantic fluency were the most useful brief tests employable in a clinical setting (AUC=0.79, p<0.001). Conclusion Verbal fluency, attention and memory were sensitive to change in early PDD and may be suitable tests to measure therapeutic response in future interventions. Impaired global cognition, attention and visual memory were the most accurate predictors for developing a PDD. Future studies could consider adopting these tests for patient clinical trial stratification.
Author(s): Lawson RA, Williams-Gray CH, Camacho M, Duncan GW, Khoo TK, Breen DP, Barker RA, Rochester L, Burn DJ, Yarnall AJ
Publication type: Article
Publication status: Published
Journal: Journal of Parkinson's Disease
Pages: ePub ahead of print
Online publication date: 19/05/2021
Acceptance date: 03/05/2021
Date deposited: 27/05/2021
ISSN (print): 1877-7171
ISSN (electronic): 1877-718X
Publisher: IOS Press
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