Effects of Various Environmental Stressors on Cognitive Performance

Abstract

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Cognitive performance, mood, and neurological status at high terrestrial elevation

“…Decrements on all seven tasks administered 1 or 6 hours after ascent to 4,600 m have been found. 43,45130 At 14 hours or 19 hours, only four tasks were still impaired, and by 38 hours or 42 hours, only two were still impaired ( Figure 23-2). Therefore, changes in performance were greatest at 1 hour or 6 hours (ie, soon after ascent), a time when the symptoms of AMS are only starting 120 140 Fig .…”

“…Impairments in psychomotor performance, mental skills, reaction time, vigilance, memory, and logical reasoning have been demonstrated at altitudes above 3,000 m. 41 - 42 Performance changes do not follow the same time course at altitude as do symptoms of AMS or moods; therefore, with time, performance will often be affected differently than symptoms or many moods. 43 " 45 Cognitive performance is usually more vulnerable to altitude than psychomotor performance, 14 -28 ' 46 and complex tasks are typically affected before simple tasks.…”

“…46,145 With time, performance at 4,600 m recovered to rates observed previously at low altitude; there was also a slight decrease in the number of 748 errors. 43 - 130 Other analyses suggested that the rate of each person's performance at low altitude (baseline) does not predict performance impairments resulting from altitude or other environmental Stressors. 43130 Cahoon 131 studied eight participants with cognitive and psychomotor tasks at 4,570 m for 48 hours or less and found that cognitive tasks showed a greater decrement in speed and accuracy than simple tasks.…”

Environmental conditions and physical stressors.

“…Hypoxic conditions cause an increase in muscle fatigue (Garner et al, 1990). Peripheral edema is a common physical condition associated with high altitude, leading to puffiness of the face, ankles, and wrists (Banderet & Burse, 1989).…”

“…Reduced sensitivity to tactile stimulation-as well as pain, smell, and taste-also have been reported (see Virués-Ortega, Buela-Casal, Garrido, & Alcázar, 2004, for a review of neuropsychological impacts of altitude exposure). Visual difficulties include significant impairment in visual acuity (Davis et al, 1995); tunnel vision (Harding & Mills, 1983); slower visual reaction times, particularly to low-intensity visual stimuli (Banderet & Burse, 1989); and limitations on night vision abilities. Additionally, dangerous visual hallucinations that may result in further impairments in judgment and decision making have been reported, which potentially are responsible for deaths during recreational ascents to high altitudes (West, 1986).…”