Classification of tinnitus.

Classification in general serves a number of purposes. In relation to tinnitus there are particular problems because the cause in only rarely known and the mechanism is not known at all. This means that firm classifications tend to be misleading and serve little purpose other than to delude the doctor and the patient. The aim in this paper therefore is to examine the various ways in which information (whether scientific or clinical) about tinnitus can be organized so as to help diagnosis, management or research towards recognition of the fundamental abnormalities. Attempts at classification based on the site of the lesion and on speculation about its cause are described. Classification is analysed according to (1) patients' own reports, (2) doctors' clinical observations, (3) various techniques of measurement, (4) associated phenomena and (5) results of treatment. From these various aspects a pattern emerges which, though incomplete, at least exposes rather than obscures the gaps in our knowledge.