A Differential Deficit in Time- Versus Event-Based Prospective Memory in Parkinson\u27s Disease

Objective: The aim of the current study was to clarify the nature and extent of impairment in time- versusevent-based prospective memory in Parkinson’s disease (PD). Prospective memory is thought to involvecognitive processes that are mediated by prefrontal systems and are executive in nature. Given thatindividuals with PD frequently show executive dysfunction, it is important to determine whether theseindividuals may have deficits in prospective memory that could impact daily functions, such as takingmedications. Although it has been reported that individuals with PD evidence impairment in prospectivememory, it is still unclear whether they show a greater deficit for time- versus event-based cues. Method:Fifty-four individuals with PD and 34 demographically similar healthy adults were administered astandardized measure of prospective memory that allows for a direct comparison of time-based andevent-based cues. In addition, participants were administered a series of standardized measures ofretrospective memory and executive functions. Results: Individuals with PD demonstrated impairedprospective memory performance compared to the healthy adults, with a greater impairment demonstratedfor the time-based tasks. Time-based prospective memory performance was moderately correlatedwith measures of executive functioning, but only the Stroop Neuropsychological Screening Test emergedas a unique predictor in a linear regression. Conclusions: Findings are interpreted within the context ofMcDaniel and Einstein’s (2000) multiprocess theory to suggest that individuals with PD experienceparticular difficulty executing a future intention when the cue to execute the prescribed intention requireshigher levels of executive control