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. The present project studied psychological, demographic, educational, and sleep risk factors of decreased academic performance in college undergraduates. Subjects (N = 867) completed a questionnaire packet and sleep diary. It was hypothesized that low total sleep time (TST), increased sleep onset latency (SOL), 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 equations of perceived stress (PSS) and TST.

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ObjectiveFibromyalgia 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.MethodsT1-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.ResultsFibromyalgia participants had significantly smaller hippocampi in both left (F[1,56]=4.55, P=0.037, η2p=0.08) and right hemispheres (F[1,56]=5.89, P=0.019, η2p=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).DiscussionPotential 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 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 (Mage = 70.18 years, SDage = 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, β = 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.

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.