Objective: The purpose of this paper was to provide an extensive description of a case of sopite syndrome, a manifestation of motion sickness scarcely described in the literature.
Design: The following questionnaires were used to assess sopite syndrome symptoms pre, during and post parabolic flight; Misery Scale rate, Positive and Negative Affect Scale, the Motion Sickness Assessment Questionnaire and the Epworth Sleepiness Scale.
Study sample: Case report of a 35-year old female compared to a control group (n = 26).
Results: We describe of sopite syndrome during parabolic flight. The subject reported drowsiness and she noted mood changes such as irritation and annoyance. Furthermore, she was not able to perform her assigned task. Her symptoms escalated into extreme fatigue and the inability to stay awake. Nauseogenic symptoms improved, but soporific symptoms persisted for several hours after the motion stimulus (i.e. parabolic flight).
Conclusions: This case points towards the need for controlled studies to assess the prevalence of this syndrome among the general population and select groups. Future research should focus on developing tests for personnel screening and explore treatment options.
Keywords: Motion sickness; parabolic flight; sopite syndrome; vestibular system.