Summary Evidence linking obstructive sleep apnea with cognitive dysfunction predominantly comes from clinical or select community samples. We investigated the independent cross‐sectional association of obstructive sleep apnea and sleep macroarchitecture parameters with cognitive function in unselected community‐dwelling middle‐aged and older men. Four hundred and seventy‐seven Florey Adelaide Male Ageing Study participants underwent successful home‐based polysomnography. They also completed cognitive testing, including the inspection time task, Fuld object memory evaluation, trail‐making test A and B, and mini‐mental state examination. Multivariable regression models examined independent cross‐sectional associations of obstructive sleep apnea and sleep macroarchitecture parameters with cognitive function. In univariable analyses, a higher apnea–hypopnea index and percentage of total sleep time with oxygen saturation <90% were associated with worse trail‐making test A performance (both p < .05). A higher apnea–hypopnea index was also associated with worse trail‐making test B performance and slower inspection time (both p < .05). In adjusted analyses, obstructive sleep apnea and sleep macroarchitecture parameters were not associated with cognitive function (all p > .05). In age‐stratified analysis in men ≥65 years, greater stage 1 sleep was independently associated with worse trail‐making test A performance, whereas greater stage 3 sleep was independently associated with better trail‐making test A performance (both p < .05). Our findings suggest that obstructive sleep apnea is not independently associated with cognitive function. In older, but not younger, men, light sleep was associated with worse attention, whereas deep sleep was associated with better attention. Longitudinal population‐based cohort studies are needed to determine if obstructive sleep apnea and disrupted sleep macroarchitecture independently predict prospective cognitive dysfunction and decline.

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Study objectives Sleep spindles show morphological changes in obstructive sleep apnea (OSA). However, previous small studies have limited generalisability, leaving associations between OSA severity measures and spindle metrics uncertain. This study examined cross-sectional associations between OSA severity measures and spindle metrics among a large population-based sample of men. Methods Community-dwelling men with no previous OSA diagnosis underwent home-based polysomnography. All-night EEG (F4-M1) recordings were processed for artefacts and spindle events identified using previously validated algorithms. Spindle metrics of interest included frequency (Hz), amplitude (µV 2), overall density (11–16 Hz), slow density (11–13 Hz), and fast density (13–16 Hz) (number/minute). Multivariable linear regression models controlling for demographic, biomedical, and behavioural confounders were used to examine cross-sectional associations between OSA severity measures and spindle metrics. Results In adjusted analyses, higher apnea-hypopnea index (AHI/h, as a continuous variable) and percentage total sleep time with oxygen saturation &lt;90% (TST90) were associated with decreased slow spindle density (AHI, B= -0.003, p=0.032; TST90, B= -0.004, p=0.047) but increased frequency (AHI, B=0.002, p=0.009; TST90, B=0.002, p=0.043). Higher TST90 was also associated with greater spindle amplitude (N2 sleep, B=0.04, p=0.011; N3 sleep, B=0.11, p&lt;0.001). Furthermore, higher arousal index was associated with greater spindle amplitude during N2 sleep (B=0.31, p&lt;0.001) but decreased overall density (B= -1.27, p=0.030) and fast density (B= -4.36, p=0.028) during N3 sleep. Conclusions Among this large population-based sample of men, OSA severity measures were independently associated with spindle abnormalities. Further population studies are needed to determine associations between spindle metrics and functional outcomes.

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This paper presents an initial comparison of two approaches to energy minimization of protein molecules, namely the Molecular Dynamic Simulation and the Kineto-Static Compliance Method. Both methods are well established and are promising contenders to the seemingly insurmountable task of global optimization in the protein molecules potential energy terrain. The Molecular Dynamic Simulation takes the form of Constrained Multibody Dynamics of interconnected rigid bodies, as implemented at the Virtual Reality Application Center from Iowa State University. The Kineto-Static Compliance Method is implemented in the Protofold Computer package developed in the Mechanical Engineering Department at the University of Connecticut. The simulation results of both methods are compared through the trajectory of potential energy, the Root Mean Square Deviation (RMSD) of the alpha carbons, as well as based on visual observations. The preliminary results indicate that both techniques are very effective in converging the protein structure to a state with significantly less potential energy. At present, the converged solutions for the two methods are, however, different from each other and are very likely different from the global minimum potential energy state.

Introduction The association between sleep spindles and cognitive function and the potential confounding influence of obstructive sleep apnea (OSA) remains uncertain. This study examined cross-sectional associations between sleep spindle metrics and cognitive function outcomes in community-dwelling men. Methods Men, Androgen, Inflammation, Lifestyle, Environment, and Stress (MAILES) study participants (n=477) underwent home-based polysomnography between 2010–2011 and completed the inspection time task, trail-making test A (TMT-A) and B (TMT-B), and Fuld object memory evaluation. Frontal spindle metrics derived from sleep electroencephalography included occurrence (total no. of sleep spindle events) and slow (11–13 Hz) and fast (13–16 Hz) spindle density (no./min) during N2 and N3 sleep. Results Men with OSA (any OSA and severe OSA) had significantly impaired sleep spindles (reduced occurrence and densities). In the complete study sample, higher spindle occurrence during N2 sleep was independently associated with faster inspection time (B= -0.44, 95% CI [-0.87, -0.02], p=0.041), whereas higher fast spindle density during N3 sleep was independently associated with worse TMT-B performance (B=20.7, 95% CI [0.55, 40.9], p=0.044). Furthermore, in men with severe OSA (apnea-hypopnea index ≥30/h), higher slow spindle density during N2 sleep was independently associated with worse TMT-A and TMT-B performance, whereas only higher spindle occurrence during N2 sleep was independently associated with worse TMT-A performance (all p&lt;0.05). Discussion Specific spindle metrics during N2 and N3 sleep are independently associated with cognitive function in an unselected population of men and men with undiagnosed severe OSA. The utility of sleep spindles for predicting cognitive dysfunction and decline requires further investigation.

Introduction Sleep microarchitecture metrics determined by quantitative power spectral analysis (PSA) of the electroencephalogram (EEG) have been proposed as potential biomarkers of cognitive function. However, there remain no data from community-based samples. This study examined cross-sectional associations between sleep microarchitecture metrics determined by PSA and cognitive function outcomes in community-dwelling men. Methods Men, Androgen, Inflammation, Lifestyle, Environment, and Stress (MAILES) study participants (n=477) underwent home-based polysomnography between 2010–2011. All-night EEG recordings were processed using PSA following exclusion of artefacts. MAILES participants also completed the inspection time task, Fuld object memory evaluation, and trail-making test A (TMT-A) and B (TMT-B). Multivariable linear regression models were used to determine the associations of sleep microarchitecture (relative spectral power) with cognitive function in the complete and age-stratified samples. Results Power spectral densities in theta-alpha ranges during NREM and REM sleep were associated with worse TMT-A performance, whereas higher delta density was associated with better TMT-A performance in the complete sample and men ≥65 years (all p&lt;0.05). Similar associations were observed with TMT-B performance in men ≥65 years. Furthermore, in men &lt;65 years, higher sigma density during NREM sleep was associated with faster inspection time (B= -3.14, 95% CI [-6.00, -0.27], p=0.032), whereas in men ≥65 years, higher theta density during NREM sleep was associated with faster inspection time (B = -3.33, 95% CI [-6.65, -0.02], p=0.049). Discussion PSA markers of sleep microarchitecture are independently associated with cognitive function. Longitudinal studies are needed to determine whether sleep microarchitecture metrics predict future cognitive dysfunction and decline.

Study objectives Prospective studies examining associations of obstructive sleep apnea (OSA) and sleep macroarchitecture with future cognitive function remain limited to older participants, many with baseline cognitive impairment, which may be a confounder. This study examined OSA and sleep macroarchitecture predictors of cognitive function (visual attention, processing speed, and executive function) after 8–10 years in community-dwelling middle-aged and older men. Methods Of 433 Florey Adelaide Male Ageing Study participants who underwent home-based polysomnography (2010–2011), 157 completed baseline and follow-up cognitive testing. Trail-making tests A (TMT-A) and B (TMT-B) were administered at baseline (2007–2010) and follow-up (2018–2019) examinations. Linear regression analyses examined associations of OSA and sleep macroarchitecture with cognitive task performance adjusted for baseline demographic, biomedical, and behavioural factors and cognitive performance, with sleep macroarchitecture models additionally adjusted for the apnea-hypopnea index (AHI). Results At baseline, participants were mean (SD) aged 58.9 (8.9) years with normal cognition. OSA prevalence (AHI ≥10/h) was 52.9%, with severe OSA (AHI ≥30/h) in 9.6%. Following covariate adjustment, higher N1 sleep (%) was associated with better TMT-A performance at follow-up (B= -0.04, 95% CI [-0.06, -0.01], p=0.003), whereas higher mean oxygen saturation was associated with worse TMT-A performance at follow-up (B=0.11, 95% CI [0.02, 0.19], p=0.012). Conclusions In this sample of community-dwelling middle-aged and older men, N1 sleep % and mean oxygen saturation showed independent associations with visual attention and processing speed after 8–10 years. Further longitudinal studies remain warranted to determine whether finer-grained sleep microarchitecture parameters identify individuals at risk of future cognitive dysfunction.