Sleep Mediates Age-Related Executive Function for Older Adults with Limited Cognitive Reserve.

OBJECTIVE: Sleep quantity and quality are associated with executive function (EF) in experimental studies, and in individuals with sleep disorders. With advancing age, sleep quantity and quality decline, as does the ability to perform EF tasks, suggesting that sleep disruption may contribute to age-related EF declines. This cross-sectional cohort study tested the hypothesis that poorer sleep quality (i.e., the frequency and duration of awakenings) and/or quantity may partly account for age-related EF deficits. METHOD: Community-dwelling older adults (N = 184) completed actigraphic sleep monitoring then a range of EF tasks. Two EF factors were extracted using exploratory structural equation modeling. Sleep variables did not mediate the relationship between age and EF factors. Post hoc moderated mediation analyses were conducted to test whether cognitive reserve compensates for sleep-related EF deficits, using years of education as a proxy measure of cognitive reserve. RESULTS: We found a significant interaction between cognitive reserve and the number and frequency of awakenings, explaining a small (approximately 3%), but significant amount of variance in EF. Specifically, in individuals with fewer than 11 years of education, greater sleep disturbance was associated with poorer EF, but sleep did not impact EF in those with more education. There was no association between age and sleep quantity. CONCLUSIONS: This study highlights the role of cognitive reserve in the sleep-EF relationship, suggesting individuals with greater cognitive reserve may be able to counter the impact of disturbed sleep on EF. Therefore, improving sleep may confer some protection against EF deficits in vulnerable older adults.

Development of a novel in vitro strategy to understand the impact of shaving on skin health: combining tape strip exfoliation and human skin equivalent technology.

Introduction: The removal of unwanted hair is a widespread grooming practice adopted by both males and females. Although many depilatory techniques are now available, shaving remains the most common, despite its propensity to irritate skin. Current techniques to investigate the impact of shaving regimes on skin health rely on costly and lengthy clinical trials, which hinge on recruitment of human volunteers and can require invasive biopsies to elucidate cellular and molecular-level changes. Methods: Well-characterised human skin equivalent technology was combined with a commonplace dermatological technique of tape stripping, to remove cellular material from the uppermost layer of the skin (stratum corneum). This method of exfoliation recapitulated aspects of razor-based shaving in vitro, offering a robust and standardised in vitro method to study inflammatory processes such as those invoked by grooming practices. Results: Tape strip insult induced inflammatory changes in the skin equivalent such as: increased epidermal proliferation, epidermal thickening, increased cytokine production and impaired barrier function. These changes paralleled effects seen with a single dry razor pass, correlated with the number of tape strips removed, and were attenuated by pre-application of shaving foam, or post-application of moisturisation. Discussion: Tape strip removal is a common dermatological technique, in this study we demonstrate a novel application of tape stripping, to mimic barrier damage and inflammation associated with a dry shave. We validate this method, comparing it to razor-based shaving in vitro and demonstrate the propensity of suitable shave- and skin-care formulations to mitigate damage. This provides a novel methodology to examine grooming associated damage and a platform for screening potential skin care formulations.

Sleep disruption explains age-related prospective memory deficits: implications for cognitive aging and intervention.

The high prevalence of sleep disruption among older adults may have implications for cognitive aging, particularly for higher-order aspects of cognition. One domain where sleep disruption may contribute to age-related deficits is prospective memory-the ability to remember to perform deferred actions at the appropriate time in the future. Community-dwelling older adults (55-93 years, N = 133) undertook assessment of sleep using actigraphy and participated in a laboratory-based prospective memory task. After controlling for education, sleep disruption (longer awakenings) was associated with poorer prospective memory. Additionally, longer awakenings mediated the relationship between older age and poorer prospective memory. Other metrics of sleep disruption, including sleep efficiency and wake after sleep onset, were not related to prospective memory, suggesting that examining the features of individual wake episodes rather than total wake time may help clarify relationships between sleep and cognition. The mediating role of awakening length was partially a function of greater depression and poorer executive function (shifting) but not retrospective memory. This study is among the first to examine the association between objectively measured sleep and prospective memory in older adults. Furthermore, this study is novel in suggesting sleep disruption might contribute to age-related prospective memory deficits; perhaps, with implications for cognitive aging more broadly. Our results suggest that there may be opportunities to prevent prospective memory decline by treating sleep problems.

Does the Key Task Measure Prospective Memory? Cautionary Findings from Parallel Studies in HIV Disease and Older Adults.

OBJECTIVE: Despite its brevity and face validity, little is known about the construct validity of the naturalistic "Key Task" of prospective memory (PM), in which an examinee is instructed to remind the examiner at a designated time to retrieve keys (or another belonging) placed out of sight. METHOD: Study 1 included 162 HIV+ and 52 HIV- comparison participants who completed the Key Task alongside well-validated measures of PM and a comprehensive neuropsychological battery that included everyday functioning measures. Study 2 used broadly parallel methods in 168 older community-dwelling Australians. RESULTS: Overall, the Key Task was not reliably associated with neurocognitive functioning (including clinical and experimental measures of PM), PM symptoms, or everyday functioning in either sample. CONCLUSIONS: The Key Task did not demonstrate compelling evidence of construct validity among persons living with HIV disease or older adults, which raises doubts regarding its clinical usefulness as a measure of PM.

Repeatable Battery for the Assessment of Neuropsychological Status (RBANS): Normative Data for Older Adults.

OBJECTIVE: Provide updated older adult (ages 60+) normative data for the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), Form A, using regression techniques, and corrected for education, age, and gender. METHOD: Participants (aged 60-93 years; N = 415) were recruited through the Healthy Ageing Research Program (HARP), University of Western Australia, and completed Form A of the RBANS as part of a wider neuropsychological test battery. Regression-based techniques were used to generate normative data rather than means-based methods. This methodology allows for the control of demographic variables using continuous data. To develop norms, the data were assessed for: (1) normality; (2) associations between each subtest score and age, education, and gender; (3) the effect of age, education, and gender on subtest scores; and (4) residual scores which were converted to percentile distributions. RESULTS: Differences were noted between the three samples, some of which were small and may not represent a clinically meaningful difference. Younger age, more years of education, and female gender were associated with better scores on most subtests. Frequency distributions, means, and standard deviations were produced using unstandardized residual scores to remove the effects of age, education, and gender. CONCLUSIONS: These normative data expand upon past work by using regression-based techniques to generate norms, presenting percentiles, as well as means and standard deviations, correcting for the effect of gender, and providing a free-to-use Excel macro to calculate percentiles.

Retrieval cue and delay interval influence the relationship between prospective memory and activities of daily living in older adults.

OBJECTIVE: Older adults commonly experience mild declines in everyday functioning and the strategic aspects of prospective memory (PM). This study used multiprocess theory to examine whether the strategic demands of retrieval cue type (event vs. time based) and delay interval length (2 vs. 15 min) influence the relationship between PM and activities of daily living (ADLs) in older adults. METHOD: Participants included 97 community-dwelling older adults recruited from the Western Australia Participant Pool. Participants were administered the Memory for Intentions Screening Test (MIST) and Prospective and Retrospective Memory Questionnaire (PRMQ) as part of a larger neurocognitive assessment. A knowledgeable informant completed the Activities of Daily Living Questionnaire (ADLQ), from which a cutpoint of ≥ 1 was used to classify participants into "ADL normal" (n = 37) or "mild ADL problems" (n = 60) groups. Repeated measures multivariate analysis of variance (MANOVA) controlling for age was conducted with ADL group as the between-subjects factor and either MIST or PRMQ cue and delay scores as the within-subjects factors. RESULTS: We observed a significant ADL group by PM interaction on the MIST, with pair-wise analyses showing that the mild ADL problems group performed worse than ADL normal participants on the 15-min time-based scale (p < .001, Cohen's d = 0.71). No other MIST or PRMQ cue-delay variable differed between the two ADL groups (ps > .10). CONCLUSION: Findings indicate that decrements in strategically demanding cue monitoring and detection over longer PM delays may partly explain older adults' mild problems in everyday functioning. Findings may inform neuropsychological interventions aimed at maintaining ADL independence and enhancing quality of life in older adults.

Does prospective memory influence quality of life in community-dwelling older adults?

Older adults commonly experience declines in prospective memory, which describes one's ability to "remember to remember," and can adversely affect instrumental activities of daily living and healthcare compliance. However, the extent to which prospective memory failures may influence quality of life in typically aging older adults is not well understood. One-hundred and four community-dwelling older Australians (aged 50 to 82 years) were administered a comprehensive, neuropsychological battery that included the Memory for Intentions Screening Test (MIST), Prospective and Retrospective Memory Questionnaire (PRMQ), Instrumental Activities of Daily Living Questionnaire (IADLQ), and World Health Organization Quality of Life-8 (WHOQOL-8). Multiple regressions controlling for negative affect, medical comorbidities, and other neurocognitive functions revealed an interaction between prospective memory and instrumental activities of daily living in the concurrent prediction of quality of life. Among the 39 older adults who reported multiple problems on the IADLQ, lower performance-based prospective memory (MIST) and higher self-reported prospective memory failures in daily life (PRMQ) were significantly associated with lower quality of life (WHOQOL-8). Conversely, no significant associations were observed between prospective memory and quality of life in the 65 participants without IADL problems. Prospective memory difficulties adversely impact quality of life in community-dwelling older adults who experience problems independently managing their instrumental activities of daily living. These findings extend prior literature showing that prospective memory plays a unique role in the real-world outcomes of older adults and clinical populations and highlight the need to develop effective strategies to enhance prospective memory functioning in these vulnerable groups.