Executive SummaryMotion sickness often leads to decrements in operational performance for personnel working in dynamic environments. Previous research examining pharmacological solutions for motion sickness have reported that dextroamphetamine (d-amphetamine) imparts significant protection against provocative motion, when compared to other standard countermeasures such as antihistamines, without conferring drowsiness or significant side effects. The military currently prescribes Dexedrine ® to assist with fatigue deterrence during periods of high operational tempo and/or extended flight operations. If the reported anti-motion sicknesses properties of d-amphetamine can be confirmed, the military could utilize a single medication for motion sickness and fatigue prevention. The purpose of this study was to determine the efficacy and side effect profile of this potential motion sickness countermeasure for us e in military environments. It was hypothesized that subjects in the oral d-amphetamine (10 mg, d-amphet) condition will tolerate more head movements than subjects in the placebo condition, without exhibiting performance decrements or significant side effects. Thirty-six aviation candidates, 31 male and 5 female, were recruited and randomized to one of two treatment groups (10 mg, damphet or placebo) and then exposed to passive Coriolis cross-coupling. Medication efficacy was determined by number of head movements tolerated between groups. Cognitive and medication side-effect profiles for both groups were derived from performance on the ANAM ® Readiness Evaluation System (ARES ® ) cognitive battery, measurements of near-focus visual accommodation (VA), scores on the Karolinska Sleepiness Scale (KSS), and motion sickness questionnaires. Analyses failed to discern significant differences in the number of head movements tolerated between groups or treatment effects over time on the ARES ® cognitive battery, VA, or KSS, p > 0.05. A negative linear relationship was found between Motion Sickness Susceptibility Questionnaire-Short (MSSQ-Short) scores and number of head movements (r = -.24, p < .05). In summary, d-amphetamine did not provide significant motion sickness protection when compared to placebo and no significant impacts on performance or medication-induced side effects were observed.
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Introduction
Definition and HistoryMotion sickness is the body's normal physiological response to unrecognized movement elicited by various forms of real or apparent motion. The primary signs and symptoms are nausea, vomiting, drowsiness, pallor, increased salivation, flushing/warmth, cold sweating, headache, and dizziness. The earliest writings on motion sickness and its ill effects were recorded by the ancient Greeks whose word "naus", from which the word nausea originated, means ship. Seafaring militaries have been afflicted by the detrimental effects of motion sickness for as long as countries have set out to explore and conquer other lands. In the reviews by Bard (1948), Chinn & Smith (1955), Reason andBrand (1975), andTyl...