RELIABILITY AND PREDICTIVE VALUE OF THE ELECTRICALLY-EVOKED AUDITORY BRAIN-STEM RESPONSE

The reliability and predictive value of the low-pulse-rate electrical auditory brainstem response (EABR) threshold and the high-pulse-rate p sychophysical threshold used in electrode mapping of adult cochlear im plant patients was assessed. Eight patients, all implanted with the Nu cleus multi-channel cochlear implant and experienced users, participat ed in this study. The relationship between like pulse rates of the EAB R and psychophysical thresholds was assessed and showed high correlati ons of 0.90 or higher. When the relationship between low-pulse-rate EA BRs and high-pulse-rate psychophysical thresholds was assessed the cor relation was much poorer. The best correlation of 0.75 was shown betwe en a 30-Hz EABR and the 500-Hz psychophysical threshold. This suggests that the low-pulse-rate EABR threshold is a poor predictor of the hig h-pulse-rate psychophysical threshold used in electrode mapping. Hence , if the EABR is to be a clinical tool for setting the electrodes it s hould be used cautiously and with the proper correction formula applie d.