Influence of Electrode Position on Near-Threshold Recording of Auditory Evoked Brainstem Potentials

Abstract

Use of brainstem potentials in audiology is based on identifying a response in the near-threshold range. Wave V has turned out to be the component of the brainstem potentials that can be detected with a great deal of reliability when assessment of the threshold for the particular stimulus is desirable. As the detection of Wave I can be dispensed within audiologic diagnosis, the question arises as to whether or not a non-cephalic reference electrode compared to the common lateral position of the reference electrode on the ipsilateral mastoid produces a more stable Wave V of increased amplitude. In a group of 20 normal-hearing adults, near-threshold stimulation with clicks was conducted and the brainstem potentials recorded simultaneously with the reference electrode placed in four different locations (ipsilateral mastoid, contralateral mastoid, non-cephalic electrode, and ipsilateral earlobe). At all of the three intensities studied (10 dB nHL, 20 dB nHL and 30 dB nHL), recording with the non-cephalic reference yielded the highest amplitudes, the finding being statistically significant.

Abstracts of the British Society of Audiology annual conference (incorporating the Experimental and Clinical Short papers meetings)

“…This study set out to investigate whether the effi ciency of auditory brainstem response (ABR) threshold measurement in babies was affected by (i) choice of either high forehead to ipsilateral mastoid or high forehead to nape electrode site, (ii) stimulation rate and (iii) choice of EEG reject level. Pethe et al(1998) reported a larger response when using the nape electrode. The studies by Sininger al (1997Sininger al ( & 2000 give more information related to test effi ciency but have mixed results on choice of electrode site.…”