TP 13312

•	Foreword
•	Section 1
•	Section 2
•	Neurology
•	Cardiovascular
•	Diabetes
•	Asthma
•	Other Policies
•	Contacts
•	Alternate Formats

Motion Sickness

• Frequency
• Treatment

The relationship between this condition and orientation is striking. The causes of motion sickness are both visual and mechanical, the latter arising from stimulation of the vestibular system. Animals in whom the vestibular system has been ablated or people born with non-functioning labryinths cannot be made motion sick. The cause of motion sickness has never been completely clarified but it is felt that it results from sensory conflicts, the difference between what is seen or felt and previous orientational experience. Motion sickness, for example, can occur in aircraft simulators and is more common amongst pilots experienced on the type of aircraft being simulated than it is in an inexperienced crew. It seems that the experienced pilot misses the cues of mechanical motion to which he/she is accustomed when the sensation of motion is only visually induced.

Frequency

Motion sickness increases in frequency up to puberty and then decreases. Women are more subject than men and it is more common in passengers than in aircrew. Motion sickness may be provoked by anxiety, fear or orientational insecurity. Unfortunately it can become a conditioned reflex. A trainee pilot, having been motion sick during flight, may become ill on the ground approaching an aircraft. It can be overcome by repeated exposure or adaptation and is rarely experienced by the person in charge of the aircraft (or automobile) who is aware, and braced for, changes in attitude or direction. Up to one third of military flight trainees become air sick at some point in their training and about 1 in 5 suffer
severe air sickness. Despite this less than 1% of the trainees are failed because of this problem. Adaptation depends upon gradually increasing stimulation. In trainee pilots who develop severe problems, desensitization programs have been
successfully employed.

Treatment

Motion sickness can be much reduced by the use of Scopolamine and nowadays transcutaneous administration of this medication is used in sea sickness. The drug however creates drowsiness and cholinergic effects and is not suitable for pilots. Small doses of the drug may be used in the initial phases of training when an instructor is in the aircraft but this must be discontinued before solo flight is undertaken. There is no place for prolonged drug therapy in aircrew.