Affiliations: [a] Centre for Advanced Research in Sleep Medicine, Hôpital du Sacré-Cœur de Montréal, CIUSSS du Nord-de-l’Île-de-Montréal, Montreal, QC, Canada
| [b] Department of Psychology, Université du Québec à Montréal, Montreal, QC, Canada
| [c] Department of Neurology, Montreal General Hospital, Montreal, QC, Canada
| [d] Department of Psychiatry, Université de Montréal, Montréal, QC, Canada
| [e] Research Centre, Institut Universitaire de gériatrie de Montréal, Montreal, QC, Canada
| [f] Unité des troubles du mouvement André Barbeau, Centre Hospitalier de l’Université de Montréal, Montreal, QC, Canada
Correspondence to: Jean-François Gagnon, PhD, Centre d’Études Avancées en Médecine du Sommeil, CIUSSS-NÎM — Hôpital du Sacré-Cœur de Montréal, 5400 Boul. Gouin ouest, Montréal, Québec, Canada, H4J 1C5.
Tel.: +1 514 987 3000 ext. 2498; Fax: +1 514 338 2531; E-mail: [email protected].
Abstract: Background:More than 75% of Parkinson’s disease (PD) patients will develop dementia. Previous studies on the cognitive predictors of dementia in PD had some methodological limitations and the cognitive tests identified as good predictors vary greatly. Objective:This prospective cohort study aims to identify the optimal cognitive predictors of dementia in PD using complementary statistical methods. Methods:Eighty PD patients without dementia underwent polysomnographic recording, a neurological examination, and a complete neuropsychological assessment at baseline. They were then followed for a mean of 4.3 years. Baseline group comparisons and survival analyses were used to identify optimal cognitive predictors. Moreover, patients who developed dementia were pair-matched at baseline according to age, sex, and education to healthy controls (2 : 1), and receiver operating characteristic curves were calculated for cognitive tests. Results:At follow-up, 23 patients (29%) developed dementia. PD patients who developed dementia had poorer baseline performance and a higher proportion of clinically impaired performance on several cognitive tests. Impaired baseline performance on the Block Design subtest was the best independent predictor of dementia (HR = 8). Moreover, the Trail Making Test part B (time) and Verbal Fluency (semantic) had the best psychometric properties (area under the curve >0.90) for identifying PD patients at risk of dementia. Conclusion:The present study identified three cognitive tests as the most accurate to detect individuals with PD at high risk of developing dementia.