Changes in Sleep Predict Changes in Affect in Older Caregivers of Individuals with Alzheimer's Dementia: A Multilevel Model Approach.

OBJECTIVES: Understanding predictors of older dementia caregivers' mood could provide insight into potential treatments which may delay institutionalization of their care recipient. Research with older noncaregivers has shown that nights characterized by better subjective sleep were associated with days characterized by higher positive and lower negative affect, and vice versa. Examining daily relationships is important, as sleep and affect are state-like behaviors that fluctuate within individuals, across time. This study was a preliminary examination of whether a sample with a greater proportion of older dementia caregivers exhibits similar daily sleep/affect associations. METHODS: Sleep diaries, actigraphy, and affect data were collected concurrently for 7 days in 55 community-dwelling, dementia caregivers (M = 62.80 years, SD = 12.21; 77.8% female). Sleep and affect were examined within- (day-to-day level) and between-persons (mean level). RESULTS: Findings for older noncaregivers were replicated for negative affect only. Specifically, nights characterized by better subjective sleep were characterized by lower negative affect, and vice versa. DISCUSSION: Examining older caregivers' daily sleep/affect association is important, because caregiving-related awakenings are unavoidable, often unpredictable, and can impact mood. Future research is needed to examine whether regularization in awakenings and/or negative affect represent important secondary, or even target, treatment outcomes for this vulnerable population.

Sleep is associated with task-negative brain activity in fibromyalgia participants with comorbid chronic insomnia.

Patients with chronic pain exhibit altered default mode network (DMN) activity. This preliminary project questioned whether comorbid disease states are associated with further brain alterations. Thirteen women with fibromyalgia (FM) only and 26 women with fibromyalgia with comorbid chronic insomnia (FMI) underwent a single night of ambulatory polysomnography and completed a sleep diary each morning for 14 days prior to performing a neuroimaging protocol. Novel imaging analyses were utilized to identify regions associated with significantly disordered sleep that were more active in task-negative periods than task-oriented periods in participants with FMI, when compared to participants with FM. It was hypothesized that core DMN areas (ie, cingulate cortex, inferior parietal lobule, medial prefrontal cortex, medial temporal cortex, precuneus) would exhibit increased activity during task-negative periods. Analyses revealed that significantly disordered sleep significantly contributed to group differences in the right cingulate gyrus, left lentiform nucleus, left anterior cingulate, left superior gyrus, medial frontal gyrus, right caudate, and the left inferior parietal lobules. Results suggest that FMI may alter some brain areas of the DMN, above and beyond FM. However, future work will need to investigate these results further by controlling for chronic insomnia only before conclusions can be made regarding the effect of FMI comorbidity on the DMN.

Fibromyalgia patients have reduced hippocampal volume compared with healthy controls.

OBJECTIVE: Fibromyalgia patients frequently report cognitive abnormalities. As the hippocampus plays an important role in learning and memory, we determined whether individuals with fibromyalgia had smaller hippocampal volume compared with healthy control participants. METHODS: T1-weighted structural magnetic resonance imaging (MRI) scans were acquired from 40 female participants with fibromyalgia and 22 female healthy controls. The volume of the hippocampus was estimated using the software FreeSurfer. An analysis of covariance model controlling for potentially confounding factors of age, whole brain size, MRI signal quality, and Beck Depression Inventory scores were used to determine significant group differences. RESULTS: Fibromyalgia participants had significantly smaller hippocampi in both left (F[1,56]=4.55, P=0.037, η (2) p=0.08) and right hemispheres (F[1,56]=5.89, P=0.019, η (2) p=0.10). No significant effect of depression was observed in either left or right hemisphere hippocampal volume (P=0.813 and P=0.811, respectively). DISCUSSION: Potential mechanisms for reduced hippocampal volume in fibromyalgia include abnormal glutamate excitatory neurotransmission and glucocorticoid dysfunction; these factors can lead to neuronal atrophy, through excitotoxicity, and disrupt neurogenesis in the hippocampus. Hippocampal atrophy may play a role in memory and cognitive complaints among fibromyalgia patients.

The role of sleep in predicting college academic performance: is it a unique predictor?

Few studies have looked at the predictability of academic performance (i.e., cumulative grade point average [GPA]) using sleep when common nonsleep predictors of academic performance are included. This project studied psychological, demographic, educational, and sleep risk factors of decreased academic performance in college undergraduates. Participants (N = 867) completed a questionnaire packet and sleep diary. It was hypothesized that low total sleep time (TST), increased sleep onset latency, later bedtimes, later wake times, and TST inconsistency would predict decreased academic performance. The most significant predictors of academic performance were high school GPA, standardized test scores (i.e., SAT/ACT), TST, time awake before arising (TWAK), TST inconsistency, and the quadratic terms of perceived stress (PSS) and TST.

Habitual Sleep, Reasoning, and Processing Speed in Older Adults with Sleep Complaints.

The relationship between habitual sleep and cognition in older adults with sleep complaints is poorly understood, because research has focused on younger adults, used experimental or retrospective quasi-experimental designs, and generally produced equivocal results. Prospective studies using sleep diaries are rare, but may provide important insights into this relationship as they offer greater ecological validity and allow for examination of the impact of night-to-night variability in sleep (an often overlooked aspect of sleep) on cognitive performance. Seventy-two older adults (M(age) = 70.18 years, SD(age) = 7.09 years) completed fourteen consecutive days of sleep diaries and paper/pencil self-administered cognitive tasks, including measures of processing speed (Symbol Digit) and reasoning (Letter Series). Regression analyses revealed increased average total wake time (TWT) during the night was associated with higher Symbol Digit scores, ß = 0.45, P < 0.05. Night-to-night variability in either total sleep time (TST) or TWT was not associated with either cognitive measure. Implications and potential explanations for these initially counterintuitive findings are discussed.