Effect of Intravenous Lidocaine Injection on EOAE for Tinnitus

Abstract

Evoked otoacoustic emissions (EOAEs) were measured in 30 patients with unilateral tinnitus before and after intravenous injection of lidocaine. After lidocaine injection, in 22 (73%) of 30 patients, tinnitus disappeared completely or diminished partially. Concerning EOAEs, in 18 (60%) of 30 patients, the amplitudes of EOAEs showed some changes. In these 18 patients, tinnitus disappeared completely or diminished partially in 17 (94%) patients. On the other hand, in 12 patients without any change of EOAEs, tinnitus was found to disappear or diminish only in five (42%) patients. The above results may indicate that intravenous lidocaine injection has the effect on cochlear micromechanics, and suggest that there is a relationship between EOAEs change and tinnitus suppression in their mechanism.