Electrode Configuration for Auditory Brainstem Response Audiometry

A vertical recording montage (Cz to the seventh cervical vertebra or C7) has been shown to yield significantly lower auditory brainstem response (ABR) threshold when compared with a horizontal or anterior-posterior montage (Sininger & Don, 1989). The present study further examines the relationship between electrode placement and the amplitude of the ABR to low-level stimuli. Four electrode arrays were compared-the commonly-used clinical configuration of forehead to ipsilateral mastoid, the vertical array from the previous study (Cz to C7), and two additional montages employing linked mastoids as reference to either the vertex or forehead electrode. ABRs were recorded simultaneously in four channels in response to 8000 click stimuli at 10, 20, and 30 dB SL from 9 male and 9 female adult subjects with normal hearing. The effect of electrode channel was significant at <.0001, with the vertical channel revealing the largest wave V amplitudes at all stimulus levels. Female subjects, as expected, produced larger ABR amplitudes than male subjects in all recording conditions, but electrode-channel effects were independent of gender.