Tactile cues in continuous operations: a preliminary study.

INTRODUCTION: Research has shown that tactile displays are an effective tool for augmenting spatial orientation and situation awareness information provided to aircraft operators. The tactile situation awareness system (TSAS) has been shown to improve flight performance in conditions of degraded visual environments and to safely maintain performance during hover over moving targets. The potential for the user to adapt and habituate to the stimulus of tactile display systems has not yet been investigated. METHODS: Four UH-60 current, rated aviators (all male) participated in the pilot study. Subjects completed four consecutive iterations of a 3-h flight profile consisting of 10 maneuvers, totaling 12 h of continuous flight. Flight performance, tactor information, responses to a discomfort questionnaire, and ratings of fatigue symptoms were recorded. RESULTS: The independent variable in all analyses was session (four levels). The results showed that performance per maneuver and proportion of stimulus cues (measure of response to cues) per maneuver were consistent across sessions using independent-samples Kruskal-Wallis tests. DISCUSSION: The findings of this preliminary assessment support the use of tactile displays (consistent with parameters of TSAS) in continuous operations since performance and proportion of stimulus cues presented was consistent over a period of 12 h. In conclusion, the system will require further experimental testing, but these preliminary findings do not suggest performance or response to be affected by any adaptation or habituation to the stimulus.

Motion sickness prevention by an 8-Hz stroboscopic environment during air transport.

INTRODUCTION: Previous research has shown that retinal slip can be a significant factor in causing motion sickness. Stroboscopic illumination may prevent retinal slip by providing snapshots of the visual environment that are brief enough so each image is stationary on the retina. METHODS: The purpose of this study was to determine the effectiveness of an 8-Hz stroboscopic environment as a motion sickness countermeasure for passengers during a nauseogenic flight in a helicopter. The study population was comprised of 18 motion sickness susceptible subjects. Subjects completed a motion sickness symptom questionnaire, a psychomotor vigilance test, weapons utilization tasks, a time estimation task, and a sustained attention task after nauseogenic flights with and without 8-Hz stroboscopic illumination in the cabin. RESULTS: Baseline-corrected scores of self-reported nausea were significantly lower after the stroboscopic condition (M = 36.57 +/- 6.95) than the nonstroboscopic condition (M = 50.88 +/- 7.36). Furthermore, the stroboscopic condition resulted in significantly better performance on the vigilance task than the nonstroboscopic condition. However, baseline-corrected scores of oculomotor symptoms were greater after the stroboscopic condition (M = 33.27 +/- 5.52) than the nonstroboscopic condition (M = 24.85 +/- 4.10). DISCUSSION: These results support the use of stroboscopic illumination as a nonpharmacologic countermeasure for motion sickness related to retinal slip. However, due to the uncontrolled nature of the flights, the possibility that these results could have been influenced by differences in motion between flights cannot be excluded. This technology should be investigated in other forms of transportation (i.e., ground vehicles).

Modafinil as a replacement for dextroamphetamine for sustaining alertness in military helicopter pilots.

INTRODUCTION: Successful military aviation operations depend on maintaining continuous day-night operations. Stimulants are easy to use and popular for sustaining performance because their utility is not dependent upon environmental or scheduling modifications. Dextroamphetamine is authorized for use by the aircrews of all U.S. military services, but its potential for abuse and subsequent addiction is of aeromedical concern. Finding an alternative stimulant, such as modafinil, that displays a low affinity for dopamine uptake binding sites would prove extremely beneficial. This study sought to establish the efficacy and safety of modafinil during actual flying operations, thus providing the operational validity desired to approve the use of modafinil for helicopter flight operations. METHODS: During two, 40-h periods of sustained wakefulness, 18 helicopter pilots (17 men, 1 woman, mean years of age = 29.5) each completed 15 flights and other evaluations, during which they received 2 of 3 experimental conditions: 3 doses at 4-h intervals of modafinil (100 mg), dextroamphetamine (5 mg), or placebo. RESULTS: Statistical results showed that modafinil, like dextroamphetamine, maintained alertness, feelings of well-being, cognitive function, judgment, risk perception, and situation awareness of sleep-deprived aviators consistently better than placebo and without side effects of aeromedical concern. DISCUSSION: Like previous research, this study strongly suggests that both drugs can maintain acceptable levels of mood and performance during sleep deprivation. The results also confirm that modafinil is well tolerated and appears to be a good alternative to dextroamphetamine for countering the debilitating mood and cognitive effects of sleep loss during sustained operations.

Airsickness prevention in helicopter passengers.

INTRODUCTION: Despite many existing treatments, airsickness is an issue of concern for soldiers being transported by helicopter. This experiment examined the efficacy of four airsickness treatments and their effects on performance. This study replicated the transport of soldiers in the cabin of an UH-60 Black Hawk helicopter performing many of the flight maneuvers potentially experienced in a night troop transport during turbulent conditions. METHODS: A double-blinded, placebo-controlled design was used to compare the effectiveness of four airsickness countermeasures to their placebo controls. There were 64 male, non-aviator subjects (ages 18-34 yr) who were recruited for the study. Of these, 16 subjects were randomly assigned to each of 4 groups: (1) promethazine (25 mg) + caffeine (200 mg); (2) meclizine (25 mg); (3) Scopolamine patch (1.5 mg); and 4) acustimulation wristband. Each individual participated twice, once with the treatment and once with placebo. RESULTS: The findings indicated that only the combination of promethazine + caffeine showed a statistically significant reduction in nausea and motion sickness severity, and an improvement in reaction time when compared with its placebo control. DISCUSSION: Data from this study indicated that of the countermeasures tested, promethazine + caffeine was the most effective at reducing airsickness while producing the fewest side effects when compared with its placebo. In addition, this study demonstrated that over-the-counter caffeine can serve as an effective stimulant counterpart to promethazine. This may be a more appealing option than employing scheduled sympathomimetic drugs in a combat environment.