Spontaneous retrieval deficits in amnestic mild cognitive impairment : a case of focal event-based prospective memory

Objective: Research on early cognitive markers of Alzheimer's disease is primarily focused on retrospective recall (of word lists, pairs of items, stories) and executive functions. However, research shows that people with amnestic mild cognitive impairment (aMCI), who are at a higher risk of developing the disease than healthy controls, are particularly impaired in remembering to do things in the future or prospective memory (PM). The aim of this study was to establish which type of event-based PM is particularly disrupted in aMCI, focal PM, based on spontaneous retrieval, or nonfocal PM that relies on strategic monitoring processes. Method:Thirty-eight aMCI individuals and 46 age- and education-matched healthy older adults identified the profession of each famous face presented (ongoing task) and, additionally, responded to certain professions (focal PM condition), or to certain physical features of a person presented (nonfocal PM). Only 4 aMCI individuals could not remember PM instructions at the end of the session, and were excluded from analyses. Results: In comparison with healthy controls, participants with aMCI were significantly impaired in the focal PM task, but not on the nonfocal task. In both groups, monitoring indices were significantly higher in the nonfocal than focal PM condition. Conclusions: The results fully replicate and extend initial findings of Chi et al. (2014) and McDaniel, Shelton, Breneiser, Moynan, and Balota (2011), showing substantial spontaneous retrieval deficits in PM performance of aMCI individuals. Possible brain mechanisms involved in this deficit are discussed and a novel hypothesis of more generic spontaneous retrieval deficits in aMCI is proposed. (PsycINFO Database Record.