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Stability of mild cognitive impairment in newly diagnosed Parkinson’s disease

Lookup NU author(s): Dr Rachael LawsonORCiD, Professor Alison Yarnall, Dr Gordon Duncan, Dr Tien Khoo, Professor David Burn



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


Background: Mild cognitive impairment (MCI) is common in early Parkinson’s disease (PD). We evaluated the stability of PD-MCI over time to determine its clinical utility as a marker of disease. Methods: 212 newly diagnosed PD participants were recruited into a longitudinal study and re-assessed after 18 and 36 months. Participants completed a range of clinical and neuropsychological assessments. PD-MCI was classified using Movement Disorders Society Task Force Level I (Montreal Cognitive Assessment <26) and II (using cut-offs of 1, 1.5 and 2 SD) criteria. Results: After 36 months, 75% of participants returned; 8% of patients had developed a dementia all of which were previously PD-MCI. Applying Level I criteria, 70% were cognitively stable, 19% cognitively declined and 11% improved over 36 months. Applying Level II criteria (1, 1.5 and 2 SD), 25% were cognitively stable, 41% cognitively declined, 15% improved and 19% fluctuated over 36 months. 18% of participants reverted to normal cognition from PD-MCI. Discussion: Cognitive impairment in PD is complex, with some individuals’ function fluctuating over time and some reverting to normal cognition. PD-MCI Level I criteria may have greater clinical convenience, but more comprehensive Level II criteria with 2SD cut-offs may offer greater diagnostic certainty.

Publication metadata

Author(s): Lawson RA, Yarnall AJ, Duncan GW, Breen DP, Khoo TK, Williams-Gray CH, Barker RA, Burn DJ

Publication type: Article

Publication status: Published

Journal: Journal of Neurology, Neurosurgery & Psychiatry

Year: 2017

Volume: 88

Pages: 648-652

Print publication date: 01/08/2017

Online publication date: 01/03/2017

Acceptance date: 14/12/2016

Date deposited: 14/12/2016

ISSN (print): 0022-3050

ISSN (electronic): 1468-330X

Publisher: BMJ Group


DOI: 10.1136/jnnp-2016-315099


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Funder referenceFunder name
J-0802Parkinson`s UK (formerly Parkinson`s Disease Society)