Aviat Space Envir Md
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Aviat Space Envir Md · Sep 2010
Comparative StudyDetermination of normative neck muscle morphometry using upright MRI with comparison to supine data.
Neck muscles are important in the static and dynamic stability of the head-neck complex. Deep neck muscles act to maintain upright posture and superficial muscles are responsible for gross movements. Previous studies have quantified neck muscle geometry using traditional supine magnetic resonance imaging (MRI). However, supine orientation removes the vertical load on the cervical spine from the head-neck complex and changes the relative orientation of the spine and neck muscles. Therefore, the purpose of this study was to demonstrate the feasibility of upright MRI to obtain neck muscle morphometric data on a spinal level-by-level basis for subjects in upright seated positions. ⋯ Comparison of neck muscle areas from the present study to a previous study incorporating supine MRI demonstrated differing trends between anterior and posterior neck muscles that may be attributable to upright orientation of volunteers and planar image orientation in the present study. Differences between supine and upright MRI identified in the present study may warrant incorporation of this technique in future spinal imaging studies.
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Aviat Space Envir Md · Aug 2010
My car is sinking: automobile submersion, lessons in vehicle escape.
In North America approximately 400 individuals per year die in submersed vehicles, accounting for 5-11% of all drownings. About half of people surveyed would let the vehicle fill with water before attempting exit. ⋯ A vehicle is most easily exited during the initial Floating Phase. We suggest the following escape procedure: SEATBELT(s) unfastened; WINDOWS open; CHILDREN released from restraints and brought close to an adult; and OUT, children should exit first.
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Aviat Space Envir Md · Aug 2010
Randomized Controlled TrialTime of day effects on neurobehavioral performance during chronic sleep restriction.
Chronic nocturnal sleep restriction results in accumulation of neurobehavioral impairment across days. The purpose of this study was to determine whether time of day modulates the effects of sleep restriction on objective daytime performance deficits and subjective sleepiness across days of chronic sleep restriction. ⋯ This study provides evidence that the circadian system has a substantial modulatory effect on cumulative impairment from chronic sleep restriction and that it facilitates a period of relatively protected alertness in the late afternoon/early evening hours when nocturnal sleep is chronically restricted.
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Aviat Space Envir Md · Aug 2010
Slalom walking with prism disorientation: impact on verbal and spatial tasks.
Slalom walking wearing distorting prisms has been used to study multitasking during adaptation to spatial disorientation. We address the hypothesis that slalom-prism walking could interfere specifically with concurrent spatial tasks. ⋯ Slowing of all performance parameters is consistent with a 'bottleneck' caused by task multiplexing. Competition for spatial processing resources and confusion because of similar features may cause interference between the lateralized spatial task and slalom.