Aviat Space Envir Md
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Aviat Space Envir Md · Feb 2005
Cognitive paralysis in an emergency: the role of the supervisory attentional system.
Many witnesses attest that victims of a disaster often perish because they 'freeze' in the face of danger. It has been proposed that this cognitive paralysis occurs due to temporal and cognitive constraints on survival response times while leaving open the question of which cognitive component is implicated in this behavior. ⋯ Secondly, that the main role of the SAS is to operate as a temporal buffer, enabling a survival response to be prepared prior to facing a life-threatening event and not as a real-time immediate responder. It is argued that the initial cognitive paralysis differs at the cognitive and neurological levels from the more prolonged hypoactive behavior commonly seen in victims rescued from disasters and which is considered to be a form of disassociative reaction.
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The Colour Vision Study Group of Transport Canada undertook a prevalence review to ascertain the degree and type of color vision deficiency (CVD) common in different populations. This was performed as a first step toward establishing whether a bone fide occupational requirement for color vision in aviation can be determined. ⋯ Congenital CVD is present in a consequential percentage of men, but considerable variability exists in different populations (2-8%). Acquired CVD may elude detection, but if severe is also associated with loss of visual acuity and/or visual field. Senescence remains the most common and increasingly prevalent cause for acquired CVD.
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Aviat Space Envir Md · Dec 2004
Tilt table design for rapid and sinusoidal posture change with minimal vestibular stimulation.
Cardiovascular response to fast posture change can be used to model individual orthostatic response under normal circumstances and after spaceflight. We set out to construct a computer-controlled tilt table suitable for repeated sinusoidal tilt motion as well as fast, single head-up tilt (HUT). The movement profile of the table was designed to prevent muscle tensing and limit vestibular stimulation. ⋯ In this study we presented a computer controlled tilt table capable of fast posture change and sinusoidal tilts. An exploratory protocol demonstrated that the table is suitable for obtaining cardiovascular response to posture change for modeling purposes.
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Aviat Space Envir Md · Nov 2004
Randomized Controlled Trial Clinical TrialWarming by immersion or exercise affects initial cooling rate during subsequent cold water immersion.
We examined the effect of prior heating, by exercise and warm-water immersion, on core cooling rates in individuals rendered mildly hypothermic by immersion in cold water. ⋯ These results suggest that prior warming by both active and, to a greater extent, passive warming, may predispose a person to greater heat loss and to experience a larger decline in core temperature when subsequently exposed to cold water. Thus, functional time and possibly survival time could be reduced when cold water immersion is preceded by whole-body passive warming, and to a lesser degree by active warming.
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Vertigo is a frequently encountered complaint among aviators. This complaint is usually labyrinthine in origin. We present a case of a combat jet fighter pilot who experienced a vertiginous episode during flight that nearly resulted in a mishap. ⋯ Coiling of the aneurysm was performed. This case emphasizes the importance of performing a complete vestibular evaluation in aviators with acute vertigo. Since central nervous system causes may be responsible for vertiginous events, and when undiagnosed may result in a recurrence during flight, magnetic resonance scanning should be considered in those with no obvious peripheral cause for their vertigo.