On-line computer scoring of the auditory brainstem response for estimation of hearing threshold

Auditory brainstem responses (ABRs) to click stimuli have become established as a useful indicator of hearing thresholds in infants and young children. Although the investigation is objective in so far as the patient is concerned, a subjective element remains in the decision by the operator as to whether or not an ABR is present in an averaged waveform. A simple on-line computer detection technique is described which removes some of the reliance placed upon the operator. The technique employs a scanning window for correlation and amplitude analysis of pairs of averaged ABR waveforms. The reliability and accuracy of computer and operator scoring of 25 thresholds in normally hearing adults and 50 thresholds in infants and young children with suspected hearing impairment have been investigated. In the adult group, 96% of computer estimates of the threshold were within +/- 10 dB of the subjective hearing threshold, compared with 92% for operator scoring. There were 92% of computer and operator scores within +/- 10 dB of each other. In the patient group there was equally good agreement between computer and operator scoring with 90% of the thresholds within +/- 10 dB of each other; the incidence of possible false-positive thresholds was also lower with computer scoring. This on-line scoring technique, therefore, offers useful assistance to the operator; requires only limited computing power, and is suitable for use in a routine clinical environment.