Does tinnitus originate from hyperactive nerve fibers in the cochlea?

Abstract

AbstractThis paper discusses the possibility of a localized peripheral origin of tinnitus. A working hypothesis is that tinnitus represents either aperiodic or periodic hyperactivity in the spontaneous activity of nerve fibers originating from a restricted place on the basilar membrane. The limited physiological data available support both hyperactive and hypoactive nerve fiber. Psychophysical data are not easy to interpret. Subjective descriptions and category scaling are too dependent on individual experience. Pitch matching can be reliable, but cannot distinguish between peripheral or central tinnitus. In one experiment we compared the masking of tinnitus to the masking of a pure tone, where the signal frequency and level were obtained from the tinnitus pitch and loudness matching. The results indicate that the broad tinnitus masking patterns are not typically due to the poor frequency resolution observed in sensorineural hearing loss. However, in a few subjects there was some correspondence between the shape of the tuning curve and the tinnitus masking pattern. In another study, we masked tinnitus with narrowband noises of different bandwidths. In some patients, there was a ‘critical bandwidth’ effect; wider masker bandwidths required greater overall sound pressures to mask the tinnitus. We conclude that the results from these studies taken together indicate that there are different types of tinnitus, some of which may have a localized peripheral origin.