The comparison of threshold of hearing obtained by tonal auditory brainstem response and pure tone audiometry of adults with normal hearing and sensorineural hearing loss

In this study, tonal auditory brainstem response and pure tone audiometry thresholds in 80 ears of 21 normally hearing adults and 28 patients with hearing loss in 0.5, 1, 2, 4 kHz frequencies were compared to each other.In adults with normal hearing, correlation were found to be 0.41 (p=0.014) and 0.58 (p<0.0001) between pure tone and tonal auditory brainstem response thresholds at frequencies of 2 and 4 kHz, respectively. The correlations were positive and moderate. There were no significant correlation between pure tone and tonal auditory brainstem response thresholds in 0.5 (r=0.231, p=0.182) and 1 kHz (r=0.018, p=0.917). Thus, we can conclude that Cronbach?s alpha values at 2 and 4 kHz were 0.562 and 0.705, respectively. Tonal auditory brainstem response thresholds reflects pure tone thresholds extremely reliable at 2 and 4 kHz. However, in adults with sensorineural hearing loss, higher correlations were observed when tonal auditory brainstem response thresholds compared to pure tone thresholds at all frequencies. Correlation coefficients (r) were found to be 0.889 at 0.5 kHz, 0.882 at 1 kHz, 0.936 at 2 kHz and 0.793 at 4 kHz (p<0.0001). Cronbach?s alpha values were 0.929 at 0.5 kHz,0.931 at 1 kHz, 0.967 at 2 kHz, 0.881 at 4 kHz.The reliability of tonal auditory brainstem response reflecting thresholds was significantly high in all group. Across all subjects, (those with normally hearing and those with hearing loss) the tonal auditory brainstem response thresholds were higher than pure tone thresholds. The mean differences between tonal auditory brain stem response (dB nHL) and pure tone (dB HL) thresholds across subjects with normally hearing were 13, 14, 7 and 5 dB HL for 0.5, 1, 2, 4 kHz, respectively (p<0.0001, p<0.0001, p<0.0001, p=0.0004). Across subjects with sensorineural hearing loss, the mean differences were 13, 12, 7 and 8 dB HL for 0.5, 1, 2, 4 kHz respectively difference between thresholds (p<0.0001, p<0.0001, p<0.0001, p=0.0003).In adults with normally hearing, it was found that click evoked auditory brain stem response thresholds at 0.5, 1, 2 kHz (Cronbach alpha values were ?=0.589, ?=0.573, ?=0.575), respectively. In 4 kHz, the reliability was moderate (?=0.734). In adults with sensorineural hearing loss, it was found that low reliability at 1 kHz (?=0.747) and high reliability at 2 and 4 kHz (?=0.946, ?=0.913) respectively.In this study, the normative data were created for tonal auditory brainstem response. Wave V. latencies at 80, 60, 40, 20 dB nHL intensity were recorded and analyzed in adults with normally hearing. And it was compared with the values of adults with sensorineural hearing loss.In ABR recordings of most (%97) of the adults with normal hearing, waves I and III were present as a response to 2 and 4 kHz tones at an intensity of 80 dB nHL. However, the percentage of wave V as a response to 0.5 and 1 kHz tone burst was 71 percent and 82 percent in normal hearing.As a result, tonal auditory brainstem responses may be used in clinically with reasonable accuracy to estimate pure tone thresholds in adults with sensorineural hearing loss.