[Paradoxical vestibular reaction in patients with consciousness disorders (nystagmographic recording)]

In 32 patients with coma of varying intensity and aetiology the effect of light on caloric nystagmus was studied. During consciousness disturbances a light stimulus provoked or increased the intensity of induced caloric nystagmus. This reaction was thus a reverse (paradoxical reaction) of that observed in waking state. Photic stimulation may provoke the rapid phase of nystagmus through facilitating impulses coursing from the subcortical or cortical visual centres to Cajal's nuclei and then through the reticular formation to the vestibulo-oculomotor system. In waking state these impulses are inhibited while in precomatic state they may become prevalent. The paradoxical reaction disappears in deep coma together with all vestibular reactions.