The sopite syndrome (/soʊˈpaɪt/; from Latin sopire 'to put to sleep')[1] is a neurological disorder that relates symptoms of fatigue, drowsiness, and mood changes to prolonged periods of motion.
[3] Typical responses include: The sopite syndrome is distinguished from other manifestations of motion sickness (i.e. nausea, dizziness, etc.)
People who operate automobiles, airplanes, etc., may experience impaired motor function due to the motions of the vehicle.
The sopite syndrome may therefore contribute to motor vehicle accidents in which automobile operators fall asleep at the wheel.
[4] A subject experiencing the sopite syndrome on a frequent basis may increase the number of hours spent sleeping by fifty percent.
A study of motion sickness occurrences in workers on an offshore oil vessel showed a large majority of participants experienced mild symptoms of fatigue.
Also, the length of time exposed to vehicular motion did not appear to affect the occurrence (or lack thereof) or severity of the sopite syndrome.
A study of motion-induced effects on the P50 potential (a measure of arousal) showed that subjects exposed to motion environments experience decreased sensory gating, which involves the filtering of information in the brain.
[7] In the case of Space Motion Sickness, the unweighting of otolith organs can lead to a sensory mismatch between the visual, vestibular, and somatosensory systems.
Subjects were exposed to vection-producing environments (virtual reality, for example) and symptoms were evaluated using a Simulator Sickness Questionnaire.
Studies have shown that animals exposed to motion environments commonly exhibit drowsiness and disinclination for activity.
Antihistamines are commonly used to treat motion sickness; however, side effects include drowsiness and impaired cognitive abilities.
Modafinil appears to be effective when taken in combination with anticholinergics such as scopolamine, but studies of Modafinil-only treatments for motion sickness remain inconclusive.
[12] Motion sickness is measured based on the cumulative ratings of all these symptoms without distinguishing different levels for each effect.
[12] This questionnaire may more accurately determine how subjects experience sopite symptoms relative to other motion sickness effects.
A study in which the optokinetic drum was used to test the symptoms of the sopite syndrome showed increased mood changes in response to the visual cues, though these effects were compounded by other environmental factors such as boredom and lack of activity.