AN ANIMAL-MODEL OF TINNITUS - A DECADE OF DEVELOPMENT

Although tinnitus affects approximately 9 million people in the United States, a cure remains elusive and the mechanisms of its origin are s peculative. The crucial obstacle in tinnitus research has been the lac k of an animal model. Over the last decade we have been creating such a model by combining a variety of methodologies, including a behaviora l component, to allow for the detection of tinnitus perception. Initia lly, 2-deoxyglucose had been used to map changes in the metabolic acti vity after unilateral destruction of the cochlea. It has been found th at the initial decrease of the metabolic rate in the auditory nuclei r ecovered to preoperative values, which could be attributable to the de velopment of tinnitus. The spontaneous activity oi single units record ed from the inferior colliculus before and after salicylate administra tion revealed an increase of discharges, which might reflect the prese nce of salicylate-induced tinnitus. Recent data have confirmed, and fu rther elaborated this observation, including the discovery of abnormal , epileptic-like, neuronal activity. Finally, the authors have develop ed a behavioral model of tinnitus, tested it extensively, and used it to measure tinnitus pitch and loudness. The model is presently used fo r investigating the hypotheses for the mechanisms of tinnitus.