Auditory reaction times in patients with chronic tinnitus with normal hearing

This study aimed to compare reaction times (RTs) to auditory stimuli of two groups of normal-hearing subjects differing only in terms of tinnitus sensation.

The RTs to auditory stimuli as a psychophysical measurement for threshold and suprathreshold hearing are said to provide a behavioral clue to some aspects of neural processing in the auditory system.

To explore how patients with tinnitus perceive the intensity of threshold and suprathreshold sound stimuli, RTs were obtained from normal-hearing subjects with tinnitus (experimental group, N=15) and from normal-hearing subjects without tinnitus (control group, N=15) by means of exposure to two different sets of frequencies: the tinnitus frequencies and the nontinnitus frequency of 1,000 Hz.

There were significant differences in RTs in the experimental group and in the control group not only for the tinnitus frequencies, but also for the nontinnitus frequency of 1,000 Hz. The experimental group had shorter RTs than did the control group at sensation levels (SLs) near the threshold, with no significant differences between groups at sound stimuli in the suprathreshold intensity range.

It is assumed that the above-mentioned reduction in RTs shows a dysfunction of cochlear mechanisms contributing to tinnitus. Conversely, tinnitus also can be considered as an additional auditory input leading to shorter RTs at SLs near the threshold. The current study suggests that the reaction time procedure to auditory stimuli offers complementary information on tinnitus sensation and might be a valuable method in demonstrating general differences and tendencies that have been neglected so far. Analysis for the mechanisms of tinnitus sensation allows for the possibility of facilitating the process of tinnitus habituation and, ultimately, the relief from it.