Acute vestibular paralysis in herpes zoster oticus.

A case of herpes zoster oticus is presented in which the lateral and superior semicircular canals of the labyrinth were affected unilaterally. The results of several electronystagmographic examinations are described and correlated with the patient's description of symptoms. This case study indicates that disease affecting the lateral semicircular canal is reliably detected by the conventional caloric test. However, the fact that the posterior semicircular canal remained intact could not be inferred from the results of the caloric test in this case. Also the appearance of nystagmus upon eye closure appears to have been a more sensitive index of the state of the disease process than was the caloric test.