Statistical Analysis of Pure Tone Audiometry and Caloric Test in Herpes Zoster Oticus

OBJECTIVES Pure tone audiometry and caloric test in patients with herpes zoster oticus were performed to determine the biologic features of the varicella zoster virus (VZV) and the pathogenesis of vestibulocochlear nerve disease in herpes zoster oticus. STUDY DESIGN A retrospective chart review of 160 patients with herpes zoster oticus was designed in order to determine the classic characteristics of vestibulocochlear nerve disease associated with the syndrome. Speech frequency and isolated high frequency acoustic thresholds were analyzed based on severity of facial paralysis and patient age. Patients without cochlear symptoms were selected randomly, and audiological function was evaluated. Patients with symptoms of vestibular dysfunction underwent the caloric test, and canal paresis was analyzed according to the severity of facial paralysis and the age of each patient. RESULTS Among the 160 patients, 111 exhibited pure tone audiometry; 26 (79%) of the patients with cochlear symptoms and 44 (56%) of the patients without cochlear symptoms had abnormal audiological data. Among the patients without cochlear symptoms, 15 (19%) had hearing loss at speech frequency, and 42 (54%) had hearing loss isolated to high frequency. The incidence of cochlear symptoms in herpes zoster oticus was not related to the severity of facial paralysis. The incidence of patients with isolated high frequency hearing loss statistically increased with age, however the incidence of patients with speech frequency hearing loss did not increase. Thirteen patients complained vertigo, and the incidence of vestibular disturbances and the value of canal paresis in the caloric test increased to statistical significance in parallel with increasing severity of facial paralysis. CONCLUSION Mild or moderate cochlear symptoms with high frequency hearing loss were related to age, and severe vestibular symptoms were related to the severity of facial paralysis after onset of herpetic symptoms. This study might suggest us a clue to the pathogenesis of vestibulocochlear nerve disease in herpes zoster oticus.