Effect of dopaminergic medications on Montreal Cognitive Assessment in Parkinson's disease patients

Background: It is unknown whether dopaminergic medications affect the overall and individual cognitive function scores of the Montreal Cognitive Assessment (MoCA) in White and Black patients with Parkinson's disease (PD). A study on this would have significant implications in clinical practice and research. Methods: We compared the overall and individual cognitive function scores of the MoCA and the Unified PD Rating Scale motor (UPDRS-III) scores at medications Off/On status in White patients and Black patients with PD in any individual or combined groups. We also compared other motor, non-motor (UPDRS-I/-II/-IV, depression/ anxiety) and quality of life (PD-QoL-39) scale scores between White patients and Black patients. Results: In 68 patients recruited (40/28 White/Black, comparable in ages and disease durations), dopaminergic medications did not make significant differences in overall MoCA scores but significantly improved the UPDRSIII motor scores at similar magnitudes in all groups. There was a slight improvement in naming and abstraction and worsening in delayed recall when on medications among these groups. There was no difference in other motor, non-motor, and QoL scores, except less social support in Black patients compared to White patients. Conclusions: Dopaminergic medications do not significantly affect the overall MoCA score (except a few individual cognitive functions) in White and Black patients with PD despite significant improvement in motor symptoms in all groups in this study. There is no difference in other motor, non-motor, and QoL scores, except less social support in Black patients compared to White patients. This study has significant implications in practice and research.