Introduction: Conductive hearing loss attenuates and delays sound transmission in the middle ear. It can lead to a variety of central auditory processing disorders which may persists even after the elimination of peripheral auditory system problems. Temporal processing, an aspect of central auditory processing, is important for understanding speech and involves temporal resolution, temporal ordering, temporal integration and temporal masking. This study aimed at assessing the effects of conductive hearing loss on the ability temporal resolution using the Gap In Noise test (abbreviated hereafter as GIN).
Materials and Methods: This noninvasive analytic-prescriptive study was conducted on 13 persons with bilateral slight to moderate conductive hearing loss and 13 persons with normal hearing. Their age ranged from 20 to 50 years and they were matched for age and sex condition. Approximate threshold and percent of correct answers in GIN test obtained, then analyzed with nonparametric Mann-Whitney and Wilcoxon tests for between-group comparisons.
Results: There was no meaningful difference in approximate threshold and percent of correct answers between two gender and the tested ear in each group (p>0.05). The mean approximate threshold of people with conductive hearing loss was significantly (P=0.003) higher than that of the normal group and, as expected, the mean percent of correct answers was lower than normal group (right ear P=0.000, left ear P=0.000).
Conclusion: Increasing approximate threshold and decreasing the percent of correct answers, the conductive hearing loss has an adverse effect on some parts of central auditory pathway and reduces the ability of temporal resolution.