Event-related potentials and cognition in Parkinson's disease: An integrative review

- This review provides a comprehensive overview of ERP correlates of cognition in PD.
- P3b latency and MMN amplitude are sensitive to PD dementia.
- P3a amplitude is a potential marker of PD disease progression.
- ERP correlates of executive functioning may index dopamine-related dysfunction.
- Our findings support the heterogeneity of cognitive changes in PD.

Cognitive impairment is a common non-motor symptom of Parkinson's disease (PD), but the nature of cognitive changes varies considerably between individuals. According to the dual-syndrome hypothesis, one cluster of patients is characterized by deficits in executive function that may be related to fronto-striatal dysfunction. Other patients primarily show non-frontal cognitive impairments that progress rapidly to PD dementia (PDD). We provide a comprehensive review of event-related potential (ERP) studies to identify ERP measures substantiating the heterogeneity of cognitive impairment in PD. Our review revealed evidence for P3b and mismatch-negativity alterations in PDD, but not in non-demented PD, indicating that alterations of these ERPs constitute electrophysiological markers for PDD. In contrast, ERP correlates of executive functions, such as NoGo-P3, N2, and error(-related) negativity (Ne/ERN), appear to be attenuated in non-demented PD patients in a dopamine-dependent manner. Hence, ERP measures confirm and yield distinct electrophysiological markers for the heterogeneity of cognitive impairment in PD. We discuss limitations and open questions of the ERP approach and provide directions and predictions for future ERP research.