Prospective memory difficulties in adults aged 60 and above with subjective memory complaints

Subjective memory complaints (SMCs) refer to individuals' self-reported memory problems in the absence of objective evidence. Subjective memory complaint has been recognized as an early indicator of the future development of dementia. Although neuropsychological evaluations for dementia typically focus on retrospective memory, SMC can manifest in both retrospective and prospective memories (PMs). Considering that impairments in PM reflect subtle cognitive decline in older adults and may be more pronounced in the preclinical stages, this study investigates whether PM is differentially impaired in older adults with SMC.

The study included 30 individuals with SMC and 30 healthy controls aged 60 or older. To assess PM, participants completed experimental tasks (event-based conditions with focal and nonfocal cues, and time-based conditions) and naturalistic tasks.

Among the experimental PM tasks, event-based PM tasks exhibited no significant group differences. However, the SMC group demonstrated lower PM accuracy (p = .001) and less strategic monitoring behavior (p < .01) in time-based PM tasks than the controls. Among naturalistic tasks, the SMC group showed significantly poorer performance than the control group on time-based subtasks (p = .010), particularly at long intervals (p = .006).

Time-based PM tasks are sensitive to detecting early cognitive decline in individuals with SMC, who exhibit intact performance on neuropsychological tests. The findings enhance our understanding of the cognitive profiles of individuals with SMC and provide opportunities for early intervention in clinical settings.