Involuntary motor phenomena in the locked-in syndrome.

Several involuntary movements were observed in patients who were totally immobile except for vertical gaze due to bilateral pyramidal transverse lesion at the pontine or midbrain level. In those conscious locked-in patients extensor spasms and flexor spasms could be elicited by nonspecific stimulation. Mimic pain reactions, pathological crying, and primordial screaming ("cat crying') were also noted. Other motor patterns were whining, moaning, groaning, sighing, and yawning. The pathophysiological implications of these observations are discussed.