Objectives: Sleep quality affects memory and executive function in older adults, but little is known about its effects in midlife. If it affects cognition in midlife, it may be a modifiable factor for later-life functioning. Methods: We examined the association between sleep quality and cognition in 1220 middle-aged male twins (age 51–60 years) from the Vietnam Era Twin Study of Aging. We interviewed participants with the Pittsburgh Sleep Quality Index and tested them for episodic memory as well as executive functions of inhibitory and interference control, updating in working memory, and set shifting. Interference control was assessed during episodic memory, inhibitory control during working memory, and non-memory conditions and set shifting during working memory and non-memory conditions. Results: After adjusting for covariates and correcting for multiple comparisons, sleep quality was positively associated with updating in working memory, set shifting in the context of working memory, and better visual-spatial (but not verbal) episodic memory, and at trend level, with interference control in the context of episodic memory. Conclusions: Sleep quality was associated with visual-spatial recall and possible resistance to proactive/retroactive interference. It was also associated with updating in working memory and with set shifting, but only when working memory demands were relatively high. Thus, effects of sleep quality on midlife cognition appear to be at the intersection of executive function and memory processes. Subtle deficits in these age-susceptible cognitive functions may indicate increased risk for decline in cognitive abilities later in life that might be reduced by improved midlife sleep quality. (JINS, 2018, 24, 67–76)

Background: Sleep disturbance is a common consequence of providing care to a loved one with Alzheimer's disease (AD). We explored the usefulness of the Pleasant Events and Activity Restriction (PEAR) model for predicting multiple domains of sleep disturbance.

Methods: Our sample consisted of 125 spousal AD caregivers. Participants completed the Pittsburg Sleep Quality Index (PSQI) and were questioned regarding the frequency with which they engaged in pleasant events and the extent to which they felt restricted in engaging in social and recreational activities in the past month. Participants were classified into one of three groups: HPLR = High Pleasant Events + Low Activity Restriction (= reference group; N = 38); HPHR/LPLR = either High Pleasant Events + High Activity Restriction or Low Pleasant Events + Low Activity Restriction (N = 52); and LPHR: Low Pleasant Events + High Activity Restriction (N = 35). These three groups were compared on the seven subscales of the PSQI.

Results: Significant differences were found between the HPLR and LPHR groups on measures of subjective sleep quality, sleep latency, habitual sleep efficiency, sleep disturbance, and daytime dysfunction. Additionally, significant differences were found between the HPLR and HPHR/LPLR groups on subjective sleep quality, sleep latency, and habitual sleep efficiency, and between the HPHR/LPLR and LPHR groups on sleep disturbance and daytime dysfunction.

Conclusions: This study provides broad support for the PEAR model and suggests that interventions focusing on behavioral activation may potentially provide benefits to non-affective domains including sleep.

Background: Sleep disturbance is common in caregivers of older adults with memory disorders. Little is known, however, about the implications of caregivers’ poor sleep with regard to their physical functioning.

Methods: In this cross-sectional study, we investigated the association between objectively measured sleep and self-reported physical functioning in 45 caregivers (mean age = 68.6 years) who completed the Beck Depression Inventory-II, the Medical Outcomes Study SF-36, and the Mini-mental State Examination, and wore an actigraph for at least three days. Our primary predictors were actigraphic sleep parameters, and our outcome was the SF-36 Physical Functioning subscale.

Results: In multivariate-adjusted linear regression analyses, each 30-minute increase in caregivers’ total sleep time was associated with a 2.2-point improvement in their Physical Functioning subscale scores (unstandardized regression coefficient (B) = 2.2, 95% confidence interval (CI) 1.0–3.4, p = 0.001). In addition, each 10-minute increase in time awake after initial sleep onset was associated with a 0.5-point decrease on the Physical Functioning subscale, although this was not statistically significant (B = −0.5, 95% CI −1.1, 0.1, p = 0.09).

Conclusions: Our findings suggest that shorter sleep duration is associated with worse self-reported physical functioning in caregivers. Longitudinal studies are needed to determine whether poor sleep predicts functional decline in caregivers.

Background: A growing body of literature suggests that caregiving burden is associated with impaired immune system functioning, which may contribute to elevated morbidity and mortality risk among dementia caregivers. However, potential mechanisms linking these relationships are not well understood. The purpose of this study was to investigate whether stress-related experience of depressive symptoms and reductions in personal mastery were related to alterations in ß2-adrenergic receptor sensitivity.

Methods: Spousal Alzheimer's caregivers (N = 106) completed measures assessing the extent to which they felt overloaded by their caregiving responsibilities, experienced depressive symptoms, and believed their life circumstances were under their control. We hypothesized that caregivers reporting elevated stress would report increased depressive symptoms and reduced mastery, which in turn would be associated with reduced ß2- adrenergic receptor sensitivity on peripheral blood mononuclear cells (PBMC), as assessed by in vitro isoproterenol stimulation.

Results: Regression analyses indicated that overload was negatively associated with mastery (β = −0.36, p = 0.001) and receptor sensitivity (β = −0.24, p = 0.030), whereas mastery was positively associated with receptor sensitivity (β = 0.29, p = 0.005). Finally, the relationship between overload and receptor sensitivity diminshed upon simultaneous entry of mastery. Sobel's test confirmed that mastery significantly mediated some of the relationship between overload and receptor sensitivity (z = −2.02, p = 0.044).

Conclusions: These results suggest that a reduced sense of mastery may help explain the association between caregiving burden and reduced immune cell ß2-receptor sensitivity.

Background. Social rhythm disruption life events are significant predictors of mood relapse in bipolar patients. However, no research has examined the relationship between these events and their hypothesized mechanism of action: disrupted sleep-wake patterns. The goal of this study was to test whether participants with major depressive disorder have a greater disruption of daily sleep and motor activity following disrupting life events when compared to normal controls.

Method. Over the course of 2 weeks, 39 normal controls and 39 individuals with major depressive disorder completed life events interviews and wore actigraphs to obtain estimates of sleep/wake activity.

Results. Statistically significant interactions indicated that the presence of at least one disrupting life event in the previous 4 months correlated with elevations in the amount of time spent awake after sleep onset [β=0·45, ΔF(1,73)=4·80, p<0·05], and decreases in the percentage of time spent asleep [β=−0·53, ΔF(1,73)=6·57, p<0·05], in depressed individuals but not in normal controls.

Conclusions. The results indicated that depressed individuals may be more susceptible to the effects of life events on sleep than normal controls. This is the first study to date to correlate life events with objective measures of sleep. However, prospective longitudinal research is necessary to clarify the temporal relationship among these variables.