Effect of Different Sites of Recording Electrodes on Auditory Evoked Potentials in Healthy Adults

ABSTRACT

OBJECTIVE: This study was designed to investigate the effect of different sites of recording electrodes on auditory evoked potentials (AEPs) in healthy adults and to analyse these potentials properly. METHOD: Eleven healthy adults, 7 males and 4 females, without any history of disease or conditions causing hearing difficulties were selected. AEPs were performed on these subjects with 4 different methods, i.e. different recording sites, Cz-Ai, Cz-Fpz, Ai-Ac, and Ai-Cs7. Auditory stimulation was given by rarefaction clicks of 75dB intensity and 11.1 Hz frequency, and responses were recorded with surface electrodes. RESULTS: The amplitudes of peak I and V were larger with vertical recordings, that is the vertex-auricle (Cz-Ai) or vertex-7th cervical spine (Cz-Cs7) recordings, compared to horizontal recordings of both auricle (Ai-Ac) or extracephalic electrodes. The largest amplitude ratio of peak V/I was with vertex-7th cervical spine (Cz-Cs7) recording. CONCLUSION: Changes in AEPs with respect to the sites of recording and reference electrodes are thought to be due to the vector of brain stem auditory nuclei and pathways. It might be helpful to consider these changes in the evaluation of brain stem lesions.