Comparison of auditory brainstem response peak measures using ear lobe, mastoid, and custom ear canal reference electrodes

Abstract

Auditory brainstem response (ABR) peak measures were compared for a custom ear canal electrode and traditional mastoid and ear lobe reference electrode sites with the assumption that the ear canal electrode would yield larger Wave I amplitudes. In this study, Waves I, III, and V latencies and amplitudes were measured and compared in twenty participants between the ages of 18 and 50, with particular interest in a potential Wave I advantage using the custom ear canal reference electrode. The statistical analysis suggested that all reference electrode sites yielded comparable results with no statistical differences in peak latency or peak-to-trough amplitude for Waves I, III, and V. Although the custom ear canal electrode did not produce larger Wave I amplitudes over the other two references, a deeper placement of the ear canal electrode might have yielded different results.

Keywords: auditory brainstem response; ear canal; reference electrode; wave I..

Figure 1

Custom ear canal electrode. The basic parts include a 32-gauge piece of silver wire and 10 mm ER3-14B ear tip (A). A small hole is punctured through the foam next to the plastic straw. The silver wire is passed through, looped around to the lateral end of the straw, and tucked back into the hole. The lateral end of the wire is then pulled until the wire is snug on the surface of the foam (B). An alligator clip connected to the electrode box is attached, and the final product serves both as an electrode and sound port.