Parametric Studies of Tinnitus Masking and Residual Inhibition

Abstract

A study was made of the relation between tinnitus masker composition (frequency, bandwidth, intensity duration) and the time course and magnitude of residual inhibition (RI). RI was determined by methods of (a) loudness estimation - where the subject varied the pointer position on a loudness scale (b) loudness balance - where the tinnitus loudness was maintained in loudness balance in the period following masking with a tone of variable intensity presented to the opposite ear. In addition, sensitivity change (temporary threshold shift, TTS) in the tinnitus and masker frequency regions was measured by determining tone thresholds (using a tracking technique) before and after masker presentation. The key findings were as follows: (I) RI depends on masker centre frequency. The frequency producing maximal RI is usually lower than the tinnitus frequency (as determined by pitch matching). (2) In some subjects only narrow-band noise produces RI. (3) RI is proportional to the masker intensity provided the tinnitus is completely masked; little or no RI is produced by a partial masker. (4) For the masker durations used (in the range 10 s to 10 min) RI duration is linearly related to the logarithm of masker duration. (5) A second masker presentation during RI does not potentiate RI. (6) Contralateral masking did not produce RI. (7) maskers producing RI also produce TTS around the tinnitus frequency. (8) The TTS magnitude and the time course of TTS appear to be related to RI.

Characterisitics and maskability of self-reported tinnitus in Adult Nigerians

“…The difference might be explained by the masker duration. Residual inhibition has been demonstrated to be related to the logarithm of the masker duration, for masker duration of 10 seconds to 10 minutes 19 . Our observed correlation between MML and residual inhibition is similar to observations of previous studies 20,21 .…”

“…Terry et al 19 observed that contralateral masking did not produce residual inhibition. We however obtained residual inhibition ranging from 2 to 50 seconds in participants with bilateral tinnitus when the worse ear was exposed to MML + 10 broad band sound for 60 seconds.…”

Temporary Suppression of Tinnitus by Modulated Sounds

“…Second, the defining effect is different-a loudness reduction in one case and a threshold elevation in the other. Third, the temporal pattern of effect is different: Tinnitus can be masked for several minutes or even hours after a masking sound is turned off (i.e., residual inhibition, see Feldmann 1971;Terry et al 1983) but sound audibility is hardly affected beyond a hundred milliseconds (e.g., Jesteadt et al 1982). Here, we use the "tinnitus masking" definition to compare the present study with previous studies.…”

Illusory percepts from auditory adaptation

“…While this method is effective in eliminating the tinnitus percept for the duration of the noise, it is seldom adopted by patients, as it accomplishes little more than replacing one auditory annoyance by another. Interestingly, a residual inhibition following the masking noise and lasting up to minutes is commonly observed 68 . It has also been reported that hearing aids properly fitted to the frequencies of hearing loss can sometimes alleviate tinnitus 3,69,70 .…”