ABSTRACT
BACKGROUND AND OBJECTIVES: Tinnitus is one of the most obscure otological pathologies. There is no universally proved treatment modality for tinnitus. Intratympanic lidocaine injection is one of the therapeutic trials. In this study, authors investigated the effects of intratympanically delivered lidocaine on the auditory system in humans. MATERIALS AND METHODS: Two percent of 0.25 cc lidocaine was delivered intratympanically to the affected ears in 5 normal hearing patients with unilateral tinnitus. We assessed auditory function by pure tone audiometry, tympanometry, tinnitus study, auditon evoked otoacoustic emissions, and ABR to observe possible druge Rects in the auditory system. In all five patients, saline was injected to the other intact ear for control purposes. RESULTS: Saline injection did not create significant changes in any of the measures. Intratympanic lidocaine injection did not make any differences between pre- and post-injection audiologic tests except otoacoustic emissions and tinnitus study. It suppressed otoacoustic emmisions and reduced loudness of tinnitus by 10 dB. Lidocaine injection did not cause any changes in latencies or amplitudes in the auditory brainstem response (ABR). CONCLUSION: These results suggest that intratympanically delivered lidocaine has an effect on the organ of Corti structures in human subjects without significantly affecting the auditory nerve or the central auditory pathways. Further investigations on the concentration and volume of intratympanically delivered lidocaine should be made in order to manage patients with tinnitus clinically.