The comparison of thresholds of hearing obtained by pure tone audiometry with klik and tonal auditory brainstem response of adults with mixed type hearing loss

Auditory brainstem response (ABR) is quite important in audiological and neurootological diagnosis nowadays. It is mostly used to identify the threshold of hearing and differential diagnosis of retrocochlear pathologies in clinics. This study aims to estimate air-bone gap in adults with mixed type hearing loss by comparing ABR latency intervals of normal hearing adults with adults with mixed type hearing loss. 30 healthy ears belonging to 19-55 years old 30 voluntary adults with normal hearing (control group) and 30 ears belonging to 19-55 years old 30 adults with mixed type hearing loss (study group) are used in this study. Before ABR measurements; pure tone audiometry, speech audiometry, acoustic immittance-metry and transient evoked auto-acoustic emission tests are conducted for all of the individuals. Absolute latencies of wave I, III and V. and their interpeak latencies are evaluated in ABR. It has been found out that click and tone burst evoked ABR latency periods are longer in adults with hearing loss than normal hearing adults (p<0.05). It is also observed that there is a weak positive relationship between air-bone gap in pure tone hearing threshold in adults with mixed type hearing loss and V. wave and I-V interpeak latency periods recorded at click and tone-burst evoked ABR (respectively r=0.28-0.50; r=0.15-0.51). It has been observed that the size of air-bone gap in pure tone hearing threshold in adults with hearing loss is directly affecting the length of wave latencies and I-V interpeak latencies in ABR. In order to identify exactly how many milisecond delay is caused by air-bone gap observed for pure tone hearing thresholds in adults with mixed type hearing loss there is a need for further studies containing more features. Key words: Audiometry, ABR, Mixed type hearing loss, Air-bone gap.