Effect of singular neurectomy on the caloric response.

PURPOSE

This study was performed to determine the contribution of the posterior semicircular canal to the vestibulo-ocular responses (VOR) from caloric stimulation of the labyrinth.

MATERIALS AND METHODS

Seven consecutive patients with disabling benign paroxysmal positional vertigo, which was treated with singular neurectomy, were tested before and after surgery with bithermal stimulation of the operated and nonoperated ears.

RESULTS

There was a significant (P = .0156) decrease in the VOR from stimulation of the operated ear following singular neurectomy. The nonoperated ear showed a variety of changes that may have resulted from compensatory mechanisms and/or utricular dysfunction.

CONCLUSIONS

We conclude that the posterior canal together with the lateral and superior canals are responsible for the VOR following caloric stimulation of the labyrinth.