Somatosensory Compensation for Loss of Labyrinthine Function

Abstract

Somatosensory compensation for vestibular deficiency was demonstrated by stepping in circles in the dark. Stepping around in small circles provides a complex pattern of afferent somatosensory signals, which in combination represent the actual movement. Labyrinth-less patients, i.e. patients devoid of labyrinthine function, reported during real as well as during apparent stepping around (on a rotating platform without stimulation of the canals) a strong sensation of rotation, as did the healthy subjects; they had a stronger somatosensory nystagmus than the healthy controls. In controls, the somatosensory and vestibular aftersensations cancelled, while the vestibular slightly outweighed their somatosensory afternystagmus. Labyrinthless subjects had no vestibulo-culomotor integrator function.