Pure-tone masking of tinnitus.

Experiments were initiated to determine the frequency most closely associated with a continuous atonal tinnitus reported by a listener with a sloping sensorineural hearing loss in his left ear. The procedure was modeled after that used to obtain a psychophysical tuning curve. Pure tones presented binaurally and monaurally between 521 and 3629 Hz were adjusted in level by the listener to just mask his tinnitus, which functioned as a signal. Masking curves for binaural and monaural masker presentation were found to be of similar shape but they varied in terms of absolute level, variability of estimates, and with regard to fine detail of the curves. The magnitude of the tinnitus as also estimated by a loudness match with a pure tone to the opposite ear. The masking levels required to mask the tinnitus were found to be consistent with those reported necessary to mask the equally loud pure tone. These findings are consistent with Langenbeck's [1953, 1965] hypothesis that tinnitus arising from the inner ear should be masked in a manner similar to an externally presented tone at the same effective level. Information derived from the masking of tinnitus by pure tones may be useful in fitting tinnitus-masking devices and also for diagnosing the site of lesion associated with tinnitus.