Longitudinal changes in prospective memory in patients with Parkinson's disease

Prospective Memory (PM) is defined as the memory for future intentions, and it is typically divided into time-based (TBPM) and event-based (EBPM). PM deficits are widely reported in patients with Parkinson's Disease (PD) but, until now, no study has yet examined their longitudinal course. Understanding how PM changes over time in PD is therefore crucial for identifying early cognitive decline and guiding timely interventions to preserve daily functioning. The present longitudinal study investigates the evolution of PM deficits over time in PD, exploring their relationship with cognitive, motor, and functional domains. A cohort of 20 non-demented PD patients was assessed between January 2017 and December 2018 and five years later, with PM evaluated using the Memory for Intentions Screening Test. Clinical, neuropsychological, and behavioral measures, including verbal memory and executive functions and questionnaires assessing apathy, functional autonomy, and perceived memory disturbances were also collected. Significant impairments were found in EBPM, with no significant differences in TBPM between baseline and follow-up. Cognitive, motor, and functional domains were strongly associated with PM performance. Regression analysis indicated that baseline global cognitive functioning predicted PM scores at follow-up. PM deficits in PD are strongly linked to broader cognitive impairments. These findings emphasize the importance of early cognitive assessment and intervention targeting global cognition to mitigate PM decline and support functional autonomy in PD patients. Further research with larger samples is needed to validate these results and explore tailored interventions.