Changes in Auditory Evoked Responses During Intravenous Lidocaine

Abstract

Auditory evoked responses in 21 cases with tinnitus were recorded before and after the administration of intravenous lidocaine. A dosage of 1 mg/kg body weight was diluted with 20% glucose (20 ml) and administered intravenously over a one—min period. The loudness of tinnitus was evaluated during electrocochleography (ECochG) or auditory brain—stem response (ABR) recordings using a score between 0 and 11. The stimulus sound was a tone burst in a frequency that corresponded to the pitch of tinnitus. AP latency on ECochG and the inter peak latency (IPL) of wave I—III and wave III—V on ABR were prolonged momentarily and tinnitus was reduced. These findings reveal that the sites of action for lidocaine are both the inner ear and the brain—stem.

Key Words:

• sites of action
• AP latency
• IPL
• inner ear
• brain—stem