Other Studies Conducted by PBA Members

Titles:

Motion Sickness Susceptibility and Height Fears

Vulnerability to Height Fears

The Effects of Promethazine on Human Performance, Autonomic Responses, and Motion Sickness Tolerance

An Evaluation of the Frequency and Severity of Motion Sickness Incidences in Personnel Within the Command and Control Vehicle (C2V)

Motion Sickness Susceptibility and Height Fears

P.A. Di Nardo, S.J. Gilbert, D. Amatuccio, A. Fox, J. Garland, F. Bucalos, J. Pate, S. Austin, S. Esposito, M. Siganoc, L. Guzy

Individuals with height fears have higher scores on self-report measures of motion sickness than non-fearful controls. This study used the optokinetic drum, a widely used procedure for inducing motion sickness, to obtain an objective measure of motion sickness susceptibility in height-fearful individuals. Fourteen height-fearful and sixteen non-fearful females were selected on the basis of scores on the Acrophobia Questionnaire (ACQ). Subjects sat in a 4 foot diameter cylinder, open at top and bottom, viewing a rotating patter of stripes, and periodically reported on specific symptoms of motion sickness, anxiety, and overall level of discomfort. The procedure was terminated when overall discomfort ratings reached a level of 4 on a 10-point scale, or after 12 minutes had elapsed. Time in drum was the main dependent measure. A Fisher's Exact Test showed that a significantly larger proportion of fearful subjects (12/14) terminated the procedure because of discomfort than non-fearful (7/16). Time in drum was negatively correlated with Anxiety Sensitivity Index scores and with subjects' ratings of fear of enclosed places, suggesting that motion sickness susceptibility is related to general levels of anxiety as well as to a specific fear of heights. These results are discussed in terms of contemporary models of the etiology of specific phobia.

Paper presented at the Association for Advancement of Behavior Therapy 31st Annual Convention - November 13-16, 1997, Miami Beach, FL.

Vulnerability to Height Fears

L. Shevalier, P. A. DI Nardo, L. T. Guzy & S. J. Gilbert

Contemporary models of specific phobia emphasize the interaction of vulnerability factors in the development of phobias. Using questionnaire measures of space and motion discomfort (SMD), anxiety sensitivity (ASI), and acrophobia in a group of college females, a multiple regression analysis showed that the combined SMD and ASI factor accounted for a greater proportion of variance in acrophobia scores that either SMD or ASI separately. Implications for understanding etiological models of specific phobia are discussed.

Paper presented to the Eastern Psychological Association, Philadelphia, PA, March 1996.

The Effects of Promethazine on Human Performance, Autonomic Responses, and Motion Sickness Tolerance

P.S. Cowings, C. Stout, W.B. Toscano, S. Reynoso, C. DeRoshia, and N.E. Miller

INTRODUCTION: The purpose of this study is to extend our understanding of the mechanisms by which pharmacological treatments improve motion sickness and space motion sickness tolerance and their impact on cognitive function. METHODS: Twelve men, ages 30 to 40 years, participated in this study. All subjects participated in four experimental conditions separated by one week intervals: a training day (no injections), a 25 mg, a 50 mg intramuscular injection of promethazine and a placebo injection. During each daily session, subjects were given four repetitions of three cognitive task batteries. On the training day baseline data were collected and subjects were trained to a performance plateau on each task. For the remaining days of the study, the order of drug or placebo injections were counterbalanced and a double-blind procedure was used. Physiological responses of heart rate, respiration rate, skin conductance level, finger pulse volume and hand temperature were continuously recorded in ambulatory subjects throughout each day (approx. 8-hrs). Daily samples of blood and saliva were also collected. RESULTS: Statistically significant reductions in performance were observed across most cognitive and psychomotor tasks on days when subjects were given 25 mg or 50 mg injections of promethazine as compared to their placebo day (p<0.01). Analyses revealed no significant difference in performance in performance between the two doses of promethazine. Regression equations indicated the equivalent of performance decrements associated with blood alcohol levels (BAL) of 0.06% for 25 mg injections and 0.11% for 50 mg. A significant increase in tolerance to rotating chair motion sickness tests was found for both doses. Increases in motion sickness tolerance with promethazine were associated with lower autonomic response levels (e.g., a significant decrease in skin conductance level). CONCLUSIONS: These data show that effective doses of promethazine used to counteract motion sickness may significantly impair susceptible individuals with respect to operational performance. Physiological data may be used to identify those subjects most susceptible to effects of medication. This work may contribute to the assessment of individual differences in effectiveness of the promethazine now used by aerospace crews as a countermeasure for space motion sickness.

Aviation, Space, and Environmental Medicine, 66: 466, 1995.
Paper presented at the Aerospace Medical Association 66th Annual Meeting, Anaheim, CA, May 7-11, 1995.

An Evaluation of the Frequency and Severity of Motion Sickness Incidences in Personnel Within the Command and Control Vehicle (C2V)

P. S. Cowings, W. B. Toscano and C. W. DeRoshia

The purpose of this study was to assess the frequency and severity of motion sickness in personnel during a field exercise in the Command and Control Vehicle (C2V). This vehicle contains four workstations where military personnel are expected to perform command decisions in the field during combat conditions. Eight active duty military men (U.S. Army) at the Yuma Proving Grounds in Arizona participated in this study. All subjects were given baseline performance tests while their physiological responses were monitored on the first day. On the second day of their participation, subjects rode in the C2V while their physiological responses and performance measures were recorded. Self-reports of motion sickness were also recorded. Results showed that only one subject experienced two incidences of emesis. However, seven of the eight subjects reported other motion sickness symptoms; most predominant was the report of drowsiness, which occurred a total of 19 times. Changes in physiological responses were observed relative to motion sickness symptoms reported and the different environmental conditions (i.e., level, hills, gravel) during the field exercise. These findings suggest that malaise and severe drowsiness can potentially impact the operational efficiency of C2V crew. However, a number of variables (e., individual's sleep quantity prior to the mission, prior experience in the C2V, etc.) were not controlled for in this study and may have influenced the results. Most notable was the fact that all subjects with previous experience in the C2V all occupied seat 4, which was anecdotally reported to be the least provocative position. Nonetheless, it was possible to determine which factors likely contributed to the results observed. It was concluded that conflicting sensory information from the subject's visual displays and movements of the vehicle during the field exercise significantly contributed to motion sickness symptoms observed in both this study and the earlier study at Camp Roberts. The objectives of this study were successfully met. The use of three converging indicators, (1) physiological monitoring, (2) subject self-reports of symptoms, and (3) performance metrics, was an effective means of evaluating the incidence of motion sickness and the impact on overall crew operational capacity within the C2V. It was recommended that a second study be conducted to further evaluate the impact of seat position or orientation and C2V experience on motion sickness susceptibility. Further, it was recommended that an investigation be performed on behavioral methods for improving crew alertness, motivation, and performance and for reducing malaise.

NASA Technical Memorandum TM-112221, 28p.,1998