Relationship between pure tone audiometry and tone burst auditory brainstem response at low frequencies gated with Blackman window.

To assess the reliability of Blackman windowed tone burst auditory brainstem response (ABR) as a predictor of hearing threshold at low frequencies. Fifty-six subjects were divided in to three groups (normal hearing, conductive hearing loss, sensorineural hearing loss) after pure tone audiometry (PTA) testing. Then they underwent tone burst ABR using Blackman windowed stimuli at 0.5 kHz and 1 kHz. Results were compared with PTA threshold. Mean threshold differences between PTA and ABR ranged between 11 dB at 0.5 kHz and 14 dB at 1 kHz. ABR threshold was worse than PTA in each but 2 cases. Mean discrepancy between the two thresholds was about 20 dB in normal hearing, reducing in presence of hearing loss, without any differences in conductive and sensorineural cases. Tone burst ABR is a good predictor of hearing threshold at low frequencies, in case of suspected hearing loss. Further studies are recommended to evaluate an ipsilateral masking such as notched noise to ensure greater frequency specificity.