The purpose of the study will be to determine the effects of the Cognitive Orientation to daily Occupational Performance (CO-OP) as a treatment program for individuals with Parkinson's disease-related cognitive impairment. The potential effects of the CO-OP on successful engagement in meaningful activities will be examined from participants' and live-in caregivers' perspectives. Effects of the CO-OP on participant-perceived health-related quality of life and caregiver burden will also be evaluated.