Prognosis of adult men with heat exhaustion with regard to postural stability and neurobehavioral effects: a 6-month follow-up study.

The medical complications of heat disorders, including hematological, cardiovascular and renal damage, have been well documented. However, very little has been written on its neurological complications. In an earlier study, we reported that men with heat exhaustion, studied 2 weeks after the acute episode, had significantly more symptoms of neurasthenia, poorer performance in short-term memory and slower reaction time. The cases (as a group) had significantly poorer postural stability. The objective of this study was to assess the prognosis of men with heat exhaustion with regard to postural stability and neurobehavioral functions 12, 3 and 6 months after the acute episode. The study is prospective in design and spans a 2-year period. All soldiers who were diagnosed to have heat exhaustion (cases) from 1 March 1998 were included in the study. For each case, a healthy soldier (matched for age, ethnicity, years of education and military vocation) was recruited to serve as control. Each subject had a neurobehavioral assessment by using the Swedish Performance Evaluation System (SPES), a computerized test battery. The postural stability of the subjects was assessed using a computerized postural sway system. Each subject took the test 2 weeks after the acute episode and repeated the test 3 and 6 months later for duration of 2 years. We report here the findings of 21 heat exhaustion cases and 18 controls, which completed all the three tests (i.e. done 2 weeks after the acute episode and 3 and 6 months later). Significant differences were only detected in some of the neurobehavioral and neurophysiological parameters between the cases and the control for first two tests but not the third test. The prognosis of adult with heat exhaustion is good. There were no significant differences in neurobehavioral tests and postural stability among the cases and controls 612 months after the episode.