Prospective memory and depression symptoms in mild cognitive impairment

Abstract Background Prospective memory involves executing an intended action in the future. This cognitive ability declines in mild cognitive impairment (MCI) and Alzheimer’s disease and affects everyday functioning. Prospective memory is usually assessed by asking participants to execute a single action in the future. We developed a complex prospective memory test that involves selecting the correct action to execute based on the context of the situation. In this study, we examined both types of prospective memory and their relationships with depression symptoms. Prospective memory involves significant cognitive effort, which could be dampened by depression symptoms. Method Participants included healthy controls ( n= 58) and persons with amnestic MCI ( n= 28) and non‐amnestic MCI ( n= 36). Before testing, all participants were informed that they should request a pill after completing each of 10 neuropsychological tests that would be administered. Simple prospective memory was assessed using the total number of correct requests. They were also told that if the most recent test involved memorization, they should request one pill, and if it did not, they should request two pills. The number of correct contingency‐based requests was used to assess complex prospective memory. The Geriatric Depression Scale (GDS) was used to measure depressive symptoms. Result Analyses of variance revealed that the amnestic MCI group performed significantly worse in simple prospective memory compared to both the controls and the non‐amnestic MCI group. The same pattern was found for complex prospective memory. We found that GDS scores did not predict prospective memory in any group. Conclusion Overall, we found that older adults with objective memory deficits (amnestic MCI) had difficulties with both simple and complex prospective memory, while those with no memory impairment (controls and non‐amnestic MCI) performed better on these tests. Importantly, depressive symptoms were not associated with performance on prospective memory tests for any of the groups. These findings suggest that prospective memory tests are useful for assessing MCI and are resistant to the impact of depressive symptoms.