Three-dimensional analysis of nystagmus induced by neck vibration.

The role of dorsal neck proprioceptive inputs to vestibular compensation was investigated in 11 patients with unilateral vestibular dysfunction. Subjects had neither spontaneous nystagmus nor disequilibrium, indicating that they were well compensated. Vibratory stimulation to the dorsal neck produced marked nystagmus. All subjects showed horizontal component directed towards the contralateral side of the lesion. Vertical and torsional components of the nystagmus were exhibited by 10 and 7 subjects, respectively. These results indicate that the neck vibration caused a discompensation in vestibularly well compensated subjects after unilateral dysfunction. In addition, the influence of neck afferent on the vestibulo-ocular reflex pathways, not only of the horizontal, but also the vertical systems, is discussed.