Cognitive impairment in Parkinson's disease: Association between patient-reported and clinically measured outcomes

•Subjective and objective cognitive impairment in Parkinson's disease are compared.•Early cognitive complaints associate with posterior cortical deficits in Parkinson's.•Visuospatial deficits underlie early cognitive complaints in Parkinson's disease.

BackgroundIn Parkinson's disease, the association between objective and patient-reported measures of cognitive dysfunction is unknown and highly relevant to research and clinical care.ObjectiveTo determine which cognitive domain-specific Montreal Cognitive Assessment (MoCA) subscores are most strongly associated with patient-reported cognitive impairment on question 1 (Q1) of the Movement Disorders Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS).MethodsWe analyzed data from 759 PD participants and 481 persons without PD with in a retrospective, cross sectional analysis using data from the NINDS Parkinson's Disease Biomarkers Program (PDBP), a longitudinal, multicenter biomarker study. The relationship between a patient-reported cognitive rating (MDS-UPDRS q1.1) and objective cognitive assessments (MoCA) was assessed using multinomial logistic regression modeling and the outcomes reported as conditional odds ratios (cOR's) representing the relative odds of a participant reporting cognitive impairment that is “slight” versus “normal” on MDS-UPDRSq1.1 for a one unit increase in a MoCA sub-score, adjusted for age and education.ResultsIn PD participants, changes in visuospatial-executive performance and memory had the most significant impact on subjective cognitive impairment. A 1-point increase in visuospatial-executive function decreased the chance of reporting a MDS-UPDRS Q1 score of “slight” versus “normal” by a factor of 0.686 (p < 0.001) and each 1 point improvement in delayed recall decreased the odds of reporting “slight” cognitive impairment by a factor of 0.836 (p < 0.001).ConclusionsConversion from a PD patient's report of “normal” to “slight” cognitive impairment may be associated with changes in visuospatial-executive dysfunction and memory more than other cognitive domains.