Temporal Processing Evaluation in Tinnitus Patients: Results on Analysis of Gap in Noise and Duration Pattern Test

Introduction: Tinnitus is a perception of sound without external source. For complete assessment of tinnitus, central auditory processing abilities should be considered in addition to the routine psychological evaluation of tinnitus characteristics. Temporal processing is one of the important auditory skills that are necessary for complex higher level auditory processing.   Materials and Methods: 20 tinnitus patients and 20 healthy volunteers without tinnitus, all with normal auditory thresholds (≤ 20 dBnHL), were enrolled in present study. Pure Tone Audiometry (PTA), Tinnitus evaluation, Gap in Noise (GIN) test and Duration Pattern Test (DPT) were applied to all participants.   Result: Analysis of GIN test revealed statistically significant increases in an approximate threshold value of gap detection in the patients group, both in right and left sides (P=0.007 and P=0.011, respectively). Comparison of percentage of correct responses in between two groups was also statistically meaningful in right and left ears (P=0.019 and P=0.026, respectively). The comparison of different parameters of DPT in two study groups revealed no significant differences in percentage of correct responses between two groups (P>0.05).   Conclusion: GIN test results identified auditory temporal resolution difficulties in patients with tinnitus, meaning that in spite of normal auditory thresholds there may be some possibility of abnormality in central auditory processing functions.