This study aimed to apply the generalizability theory (G-theory) to investigate dynamic and enduring patterns of subjective cognitive complaints (SCC), and reliability of two widely used SCC assessment tools.

G-theory was applied to assessment scales using longitudinal measurement design with five assessments spanning 10 years of follow-up.

Community-dwelling older adults aged 70–90 years and their informants, living in Sydney, Australia, participated in the longitudinal Sydney Memory and Ageing Study.

The sample included 232 participants aged 70 years and older, and 232 associated informants. Participants were predominantly White Europeans (97.8%). The sample of informants included 76 males (32.8%), 153 females (65.9%), and their age ranged from 27 to 86 years, with a mean age of 61.3 years (SD = 14.38).

The Memory Complaint Questionnaire (MAC-Q) and the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE).

The IQCODE demonstrated strong reliability in measuring enduring patterns of SCC with G = 0.86. Marginally acceptable reliability of the 6-item MAC-Q (G = 0.77–0.80) was optimized by removing one item resulting in G = 0.80–0.81. Most items of both assessments were measuring enduring SCC with exception of one dynamic MAC-Q item. The IQCODE significantly predicted global cognition scores and risk of dementia incident across all occasions, while MAC-Q scores were only significant predictors on some occasions.

While both informants’ (IQCODE) and self-reported (MAC-Q) SCC scores were generalizable across sample population and occasions, self-reported (MAC-Q) scores may be less accurate in predicting cognitive ability and diagnosis of each individual.

To investigate the relationship between the P300 event-related potential, neuropsychological measures of memory, subjective memory complaints (SMCs), and indicators of psychosocial functioning.

In this cross-sectional study of 79 community-based older adults, aged 60–75 years, participants completed online surveys and in-person neuropsychological and electroencephalogram (EEG) assessments.

Measures included: the Change subscale of the Metamemory in Adulthood Questionnaire, NIH Toolbox Emotions battery (Perceived Stress and Psychological Well-Being), Geriatric Depression Scale, Geriatric Anxiety Scale, electrocortical measures (EEG), California Verbal Learning Test, 3rd Edition, and diagnostic ratings for mild and major neurocognitive disorders based on full neuropsychological battery, clinical interview, and two-clinician consensus.

P300 amplitude was associated with long-delay verbal memory recall and diagnostic rating. SMCs were not associated with objective memory or diagnostic rating. SMCs were associated with higher perceived stress, anxiety, and depression symptoms and lower psychological well-being.

Neural indicators such as the P300 may be useful for early detection of cognitive impairment. SMCs were not a reliable indicator of early memory impairment in relation to neuropsychological or neural indicators, but may be a useful indicator of unreported stress and mood symptoms in clinical settings.

Purposeful adults may experience greater cognitive resilience because sense of purpose may help buffer against the effects of depressive symptoms and loneliness. We also evaluated whether these associations differed by race.

This study uses a wave of self-report data from the SPAN study of psychosocial aging.

Participants come from a representative sample of older adults in St. Louis.

Participants (N = 595) ages range from 65 to 78 (Mage = 71.46), with 18.3% of participants identifying as Black/African-American.

Sense of purpose was assessed with the Life Engagement Test, depressive symptoms with the Beck Depression Inventory-II, loneliness with the UCLA Loneliness Scale, and subjective cognitive decline with the AD-8.

Correlational analyses supported predictions that sense of purpose was negatively related to subjective cognitive decline, whereas depressive symptoms and loneliness were positively related (|r|s > .30, ps < .001). For loneliness, but not depression, this association was moderated by sense of purpose (b = −0.43, p < .001). A relatively high sense of purpose attenuated associations between loneliness and subjective cognitive decline. A three-way race × purpose × loneliness interaction (b = −0.25, p = .021) revealed that the buffering effects of sense of purpose on subjective cognitive decline were stronger for Black adults.

This study provided partial support for the buffering hypothesis, showing that sense of purpose may help mitigate the cognitive decrements associated with loneliness. Future research needs to consider how purpose-promoting programs may support healthy cognitive aging, particularly among Black older adults and those who experience greater social isolation.