Seasickness, How It Affects Sailors and Relationships with Land and Air Motion Effects

Seasickness or Mal de Mer is a very unpleasant experience, and most sailors, if all, had to cope with it. In its extreme form it leaves the victim unwilling to perform any task, even to assist in his or her own rescue. Motion sickness or cinetose is dependent on the magnitude of ship motion, but how it affects human operator is not unequivocal. We will review the different factors, environmental, physiological and psychological, involved in cinetose genesis and how they influence human performance. Application to land, air and space vehicles will be discussed. 1.0 INTRODUCTION Seasickness or Mal de Mer is a form of motion sickness or cinetose, like airsickness, car sickness, amusement-park-ride sickness, motion-picture sickness, Mal de Débarquement, camel sickness, flight or ship-simulator sickness, virtual reality sickness, space sickness. Almost any normal subjects will suffer from cinetose as long as the motion stimuli applied to the individual or its environment (real or virtual) are reaching a certain intensity and last enough. Delay of symptoms apparition vary, from a few minutes to many hours depending on subject susceptibility. Although the underlying neurophysiologic mechanism is still obscure, current theory are still focusing on the “sensory conflict”. Cinetoses occurs when there is a mismatch between orientation information generated by various sensors (vestibular, auditory, visual...). But among the sensors involved, the vestibular system is required (subjects without functioning vestibular end-organs are immune to cinetose) [1]. 2.0 CINETOSE SUSCEPTIBILITY There is a lot of inter-individual cinetose susceptibility differences as well as intra-individual differences. Age is an important factor: children are more susceptible than adults, with a peak susceptibility between 3 and 12, then susceptibility decrease to climb again after 60. Females are reported to be less resistant then males at any given age, with pregnancy and menses aggravating the occurrence of symptoms. Besides gender and age other factors may influence and explain why individual cinetose susceptibility may fluctuate. Sleep deprivation, fatigue will increase the susceptibility. Adaptation is a major factor to develop cinetose tolerance. It requires about 3 days to develop at sea or in space. Paper presented at the RTO AVT Symposium on “Habitability of Combat and Transport Vehicles: Noise, Vibration and Motion”, held in Prague, Czech Republic, 4-7 October 2004, and published in RTO-MP-AVT-110. RTO-MP-AVT-110 KN2 1 UNCLASSIFIED/UNLIMITED UNCLASSIFIED/UNLIMITED Report Documentation Page Form Approved OMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. 1. REPORT DATE 01 OCT 2004 2. REPORT TYPE N/A 3. DATES COVERED 4. TITLE AND SUBTITLE Seasickness, How It Affects Sailors and Relationships with Land and Air Motion Effects 5a. CONTRACT NUMBER