Prospective memory and subjective memory decline: A neuropsychological indicator of memory difficulties in community-dwelling older people

ABSTRACT

Introduction: Prospective memory difficulties are known to occur in Alzheimer’s disease, and may provide an early indicator of cognitive decline. Older people reporting high levels of subjective memory decline (SMD) but without evidence of cognitive decline on standard neuropsychological tests are increasingly considered at increased risk for Alzheimer’s disease. Therefore, the objective of this study was to investigate whether prospective memory performance is differentially impaired in older people reporting high levels of SMD as compared to a control group. Method: A total of 195 community-dwelling older adults (M_age = 73.48 years) were assessed for self-reported complaints of memory decline and allocated to either a group reporting high levels of SMD (SMD, n = 96) or a healthy control group (HC, n = 99). Groups were assessed on neuropsychological tests, an experimental prospective memory task (focal vs. nonfocal cue conditions), and a naturalistic prospective memory task. Results: The groups did not differ in performance on standard neuropsychological tests of working memory, executive attention, and episodic retrospective memory. Furthermore, on an experimental task of prospective memory (the Supermarket Shopping Trip task), although performance of both groups was better when cues for prospective memory were focal to the ongoing activity (η² = .35), the SMD group were not impaired relative to the control group. On a naturalistic prospective memory task, however, there was a small but significant effect, with the SMD group performing more poorly than the HC group (η² = .02). Conclusions: In older adults with high levels of SMD, naturalistic measures of prospective memory provide an approach to assessing memory performance that can offer a means of investigating the memory complaints of people with SMD. Identifying prospective memory difficulties in SMD also offers a focus for intervention.

KEYWORDS:

• Alzheimer’s disease
• mild cognitive impairment
• naturalistic assessment
• prospective memory
• subjective memory decline

Acknowledgements

We would like to thank the participants for their time and contribution to this study, and Fenny Muliadi and Marina Cavuoto for their assistance with study data collection and entry.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1. When the groups were compared using the MAC-Q score of ≥25, the main effect of group on the Supermarket Shopping prospective memory task was no longer significant.

2. Due to minor nonnormality, a Mann–Whitney U was run and confirmed no significant main effect for group on the combined correct free recall or cued recall: HC mean rank = 102.43, and SMD mean rank = 91.40, U = 4123.00, z = −1.515, p = .130.

3. When the groups were compared using the MAC-Q score of ≥25, there was an additional significant correlation (r = .30, p < .01) between nonfocal prospective memory performance and HVLT–R delayed free recall in the HC group. The correlation was reduced for the variables SMDT (r = .25, p < .01) and Stroop (r = .29, p < .01) with the nonfocal condition for the SMD group. No other significant changes emerged.

Additional information

Funding

This work was supported by a Commonwealth Research Training Scheme award to S.L.; and a National Health and Medical Research Council of Australia Clinical Research Training Fellowship [grant number 602543] to K.E.P.