Search

Summary: Recent studies have found associations between obstructive sleep apnea and cognitive decline. The underlying mechanisms are still unclear. Here, we investigate the associations between changes in micro‐architecture, specifically sleep spindles, and cognitive function in community‐dwelling middle‐aged and older adults, some with obstructive sleep apnea, with a focus on sex differences. A total of 125 voluntary participants (mean age 66.0 ± 6.4 years, 64 females) from a larger cohort (participants of the Brain in Motion Studies I and II) underwent 1 night of in‐home polysomnography and a neuropsychological battery (sleep and cognitive testing were conducted within 2 weeks of each other). A semi‐automatic computerized algorithm was used to score polysomnography data and detect spindle characteristics in non‐rapid eye movement Stages 2 and 3 in both frontal and central electrodes. Based on their apnea–hypopnea index, participants were divided into those with no obstructive sleep apnea (apnea–hypopnea index < 5 per hr, n = 21), mild obstructive sleep apnea (5 ≥ apnea–hypopnea index < 15, n = 47), moderate obstructive sleep apnea (15 ≥ apnea–hypopnea index < 30, n = 34) and severe obstructive sleep apnea (apnea–hypopnea index ≥ 30, n = 23). There were no significant differences in spindle characteristics between the four obstructive sleep apnea severity groups. Spindle density and percentage of fast spindles were positively associated with some verbal fluency measures on the cognitive testing. Sex might be linked with these associations. Biological sex could play a role in the associations between spindle characteristics and some verbal fluency measures. Obstructive sleep apnea severity was not found to be a contributing factor in this non‐clinical community‐dwelling cohort. [ABSTRACT FROM AUTHOR]

Aim: Species distributions across islands are shaped by dispersal limitations, environmental filters and biotic interactions but the relative influence of each of these processes has rarely been assessed. Here, we examine the relative contributions of island characteristics, marine subsidies, species traits, and species interactions on avian community composition. Location: Central Coast region of British Columbia, Canada. Taxon: Terrestrial breeding birds. Methods: We observed 3610 individuals of 32 bird species on 89 islands that spanned multiple orders of magnitude in area (0.0002–3 km2). We fit a spatially explicit joint species distribution model to estimate the relative contributions of island physical characteristics, island‐specific inputs of marine subsidies, species' traits, and biotic interactions on species distributions. Biogeographic characteristics included island area, isolation, and habitat heterogeneity, while marine influence was represented by forest‐edge soil δ15N, wrack biomass, shoreline substrate, and distance to shore. This approach also allowed us to estimate how much variation in distributions resulted from species' biological traits (i.e. body mass, feeding guild, feeding height, and nesting height). Results: Bird species distributions were determined almost equivalently by island biogeographic characteristics (23.5% of variation explained) and marine influence (24.8%). We detected variation in species‐specific responses to both island biogeographic characteristics and marine influence, but no significant effect of any biological trait examined. Additionally, we found evidence that habitat preferences were a more important driver than competitive interactions. Main Conclusions: Although most island biogeographic studies focus only on islands' physical characteristics, we found evidence for an equivalent role of marine subsidy in structuring island bird communities. Our study suggests that for small islands, disentangling the effects of island biogeographic characteristics, marine inputs, and biotic interactions is a useful next step in understanding species distributions. [ABSTRACT FROM AUTHOR]

Byline: Christie M. Lee (1), Margaret S. Herridge (2), Jonathan Y. Gabor (1), Catherine M. Tansey (2), Andrea Matte (2), Patrick J. Hanly (3) Keywords: Sleep; Insomnia; Critical illness; Adult respiratory distress syndrome Abstract: Purpose Sleep disruption is well recognized in the Intensive Care Unit. Poor sleep quality likely continues following discharge from hospital in several patients and becomes a chronic disorder in some. The aim of this study was to describe the etiology of chronic sleep complaints in survivors of ARDS. Methods Seven ARDS survivors with no previous sleep complaints who reported difficulty sleeping 6 months or more following discharge from hospital were evaluated. Sleep quality was assessed subjectively with a sleep history and the Insomnia Severity Index and objectively with polysomnography. Daytime sleepiness was assessed with the Epworth Sleepiness Scale. Results A chronic sleep disorder was identified in each patient who reported difficulty sleeping. The primary sleep disorder was chronic conditioned insomnia (5 patients), parasomnia (1 patient) and obstructive sleep apnea (1 patient). In addition, 4 patients had periodic leg movements, which was of uncertain clinical significance. Conclusion Chronic sleep disorders, which originate during the acute illness, are present in some ARDS survivors several months after discharge from hospital. If unrecognized, lack of treatment may contribute to impaired quality of life and incomplete rehabilitation from their critical illness. Author Affiliation: (1) Department of Medicine, University of Toronto, Toronto, Canada (2) Division of Critical Care, University Health Network, Toronto, Canada (3) Department of Medicine, University of Calgary, 1421 Health Sciences Centre, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada Article History: Registration Date: 01/09/2008 Received Date: 17/11/2007 Accepted Date: 19/07/2008 Online Date: 18/09/2008 Article note: Electronic supplementary material The online version of this article (doi: 10.1007/s00134-008-1277-3) contains supplementary material, which is available to authorized users.