Sopite syndrome

The sopite syndrome (/soʊˈpaɪt/; Latin: sopire, "to lay to rest, to put to sleep") is a neurological disorder that relates symptoms of fatigue, drowsiness, and mood changes to prolonged periods of motion. The sopite syndrome has been attributed to motion-induced drowsiness such as that experienced by a baby when rocked. Researchers Graybiel and Knepton at MIT first used the term "the sopite syndrome", in 1976, to refer to the sometimes sole manifestation of motion sickness, though other researchers have referred to it as "Sopite syndrome."

The sopite syndrome is classified as a symptom-complex centered on drowsiness. It may be distinguished from ordinary fatigue. Researchers have previously studied this effect through the use of rotating rooms. When subjects who had previously shown minimal susceptibility to general motion sickness and fatigue (in this particular case, four military officers) were recruited to live in a rotating room for several days, they exhibited several signs of drowsiness, such as yawning and frequent napping. Despite numerous activities designed to promote awareness and excitability, the subjects showed decreased motivation to socialize or perform physical activities. Many of these symptoms could be attributed to the vestibular stimulation of the rotating rooms.

Several symptoms are associated with the sopite syndrome. Typical responses include:

The sopite syndrome is distinguished from other manifestations of motion sickness (i.e. nausea, dizziness, etc.) in that it may occur before other symptoms of motion sickness or in their absence. The sopite syndrome may persist even after an individual has adapted to the other symptoms associated with motion-induced sickness.

The effects of the sopite syndrome may range from minor physical inconveniences to hazardous conditions. Persons who operate automobiles, airplanes, et cetera, may experience impaired motor function due to the motions of the vehicle. These impairments often result in a decreased attention span; persons who consider themselves well-rested may still succumb to drowsiness at inopportune moments. The sopite syndrome may therefore contribute to motor vehicle accidents in which automobile operators fall asleep at the wheel. However, the sopite syndrome itself does not directly result in death.

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