[Tinnitus: causes, diagnosis, therapy].

The symptom tinnitus may be due to a number of causes. Pathological processes within the sense-organ "ear" as well as non-otologic diseases may result in tinnitus. Therefore a thorough ENT diagnosis is necessary. The evaluation of the patient includes the history, ENT-status examination, audiological and vestibular findings, imaging investigations and, if necessary, examinations by other specialists. The therapy of tinnitus is difficult. If possible, the therapy should be causally orientated. Mostly, this is only the case with tinnitus caused by diseases of the external and middle ear. The therapeutic aim is the compensation of tinnitus. The most common type of tinnitus is of cochlear-synaptic origin. According to results of inner ear research new possibilities of pharmacologically influencing the cochlear synapse have been found. By intravenous application of the specific Quisqualate antagonist glutamic acid diethyl ester (GDEE) 77.2% of our patients with cochlear synaptic tinnitus noted a tinnitus reduction.