Characteristics of waveforms of facial electroneurography (ENoG) according to different electrode placement in normal persons

Jung, Yong Soo; Chung, Won Ho; Lee, Jong Chan; Ha, Byung Suk; Shin, Dong Bong; Won, Eun Young; Cho, Yang Sun; Hong, Sung Hwa

Abstract

BACKGROUND AND OBJECTIVES: Electroneurography (ENoG) is regarded as a useful test for evaluating the degree of facial nerve degeneration and predicting the prognosis of the patients with facial nerve palsy. The test results could be changed by many factors, such as electrode position, skin resistance and stimulus magnitude, etc. In this study, the waveforms of ENoG in normal persons were evaluated according to different electrode placement in the nasal alae and in the nasolabial fold, respectively.
MATERIALS AND METHODS
Twenty volunteers with normal facial function were included in this study. ENoG was recorded with the recording electrode placed in two different locations, one in the nasolabial fold and the other in the nasal alae, in each person. The recording waves were compared according to their amplitude, sharpness and types of waveform. Interside variability was compared.
RESULTS
The amplitude was not significantly different at two locations, but the sharpness was significantly increased when recorded at the nasal alae. Biphasic waveform was more common when recorded at the nasal alae than at the nasolabial fold. This meant that the masseter artifacts were present more commonly at the nasolabial fold. The average of interside variability was 22.77% (17.62) at the nasolabial fold and 23.71% (15.35) at the nasal alae (p>0.05).
CONCLUSION
Different electrode placement resulted in different waveforms. By placing the recording electrode at the nasal alae, more biphasic and sharpened waveforms were recorded and less masseter artifacts were observed.