Tone burst evoked auditory brainstem responses and clinical applications

Behavioral audiometry is one of the most effective methods to evaluate the auditory functions. Because of its subjectivity on evaluation, it may not give enough information to measure the hearing of some people. These are infants, younger children, patients that may be pretending, patients that have fallen into the coma and people who have mental retardatory. Therefore, it can not be used as a measurement method for hearing. Because of these reasons, some electrophysiological testing methods that are objective to evaluate the hearing of these peopleAuditory brainstem responses are one of the most important tools to evaluate the hearing objectively. There are usually two types of stimuli that are click and Tone Burst which is frequency specific to measure the ABR. Although click ABR may be used to provide sufficient information about hearing thresholds at high frequency, it doesn?t provide enough information about low frequency hearing thresholds. The second well- known stimuli is Tone Burst stimuli that have frequency specificity. The Tone Burst evoked responses provide frequency-specific tresholds.The aim of this study is to analyse the relation between Tone Burst evoked ABR thresholds and Pure Tone Audiometry thresholds statistically. When there is a statistically meaningful relation between these thresholds, the reference thresholds can be determined according to the relation between Tone Burst ABR and PTA thresholds. To achieve this aim, a sample group that includes 40 normal-hearing and 20 hearing-impaired subjects, was constituted according to sex and age. Tone Burst evoked ABR and PTA at 500-2000 and 4000 Hz were applied to the sample group and thresholds were collected. The differences (dB) between Tone Burst ABR (dB nHL) and the PTA thresholds (dB HL) across 40 normal-hearing subjects were 20.0, 8.0 and 6.0 dB for 500, 2000 and 4000 Hz respectively. These differences were 16.0, 6.0 and 4.0 dB for 500, 2000 and 4000 Hz respectively for the hearing-impaired subjects.Differences in the latency of Tone Burst ABR were not statistically significant in terms of gender and age. The other finding is that latency decreases as the stimuli go from low to high frequencies.Finally, the findings of current study were similar to the results from literature