Confirming pure-tone thresholds by auditory brainstem response in the geriatric population.

BACKGROUND

The aged people seeking otological consultation tend to increase for the purpose of applying for hearing disability certificate. When the subjective pure-tone thresholds (PTTs) are unreliable due to patient incooporation, the objective click auditory brainstem response (ABR) is used to confirm the hearing thresholds. In this study, we assess the accuracy of ABR thresholds in the aged and determine the "ABR confirmation criteria" for normal hearing and hearing handicap.

METHODS

This is a prospective study. ABR thresholds were compared with pure-tone thresholds (PTTs) in 100 ears of 50 subjects over 60 years of age using kappa measure of agreement. Based on receiver operating characteristic (ROC) curve and positive likelihood ratio (LR), the most appropriate "ABR confirmation criteria" for normal hearing and hearing handicap were determined.

RESULTS

According to kappa statistics, the agreement between ABR thresholds and PTTs is better in the 2- to 4-kHz region. For normal hearing, the agreement is best when confirming the average PTTs of 2, 3 and 4 kHz by the ABR threshold of 25 dB nHL (K = 0.53, p < 0.001). For hearing handicap, the agreement is best when confirming the PTTs of 3 kHz by the ABR threshold of 55 dB nHL (K = 0.60, p < 0.001). Based on ROC curve and positive LR, the ABR accuracy, for normal hearing, is excellent at a cutoff of 30 dB nHL compared with the average PTT of 2, 3 and 4 kHz. For hearing handicap, the ABR accuracy is best in excess of 55 dB nHL compared with the PTT at 3 kHz.

CONCLUSIONS

We conclude that ABR is a useful diagnostic tool to confirm the validity of pure-tone audiogram for presbycusis.