Electrophysiological analysis of peripheral facial nerve palsy with reference to the degree of impairment / 日本温泉気候物理医学会雑誌

ABSTRACT

Degeneration of facial nerve and the facial movement in patients with peripheral facial nerve palsy in early stages must be assessed. Therefore, we conducted electroneurography (ENoG) and blink reflex (BR) tests on 30 patients with unilateral peripheral facial nerve palsy.<br>In the ENoG test, transcutaneous electrical stimulation was applied to the trunk of the facial nerve on the stylomastoid foramen and the response (M-wave) evoked from the bilateral orbicularis oculi muscle was measured. The ratio of M-wave amplitude on the paralyzed side to that on the normal side was then calcu-lated.<br>In the blink reflex response test, transcutaneous electrical stimulation was applied to the supraorbital nerves and the response evoked from the orbicularis oculi muscle was measured. The response consisted of an early ipsilateral component, R1, and a late bilateral component, R2. Further, the ratio of R2 amplitude on the normal side to that on the paralyzed side and the difference in latencies of R2 between paralyzed side and normal side were calculated from each waveform thus obtained.<br>Facial muscle movement was assessed according to the grading system proposed by the Japan Society of Facial Nerve Research (in which the normal state is represented by 40 points). After examining the relationships between the score and some parameters in ENoG and BR (the ratio of M-wave amplitude, the ratio of R2 amplitude, the difference between the two sides on the latencies of R2) on each patient, we found close correlations between the score and some parameters. In summary, assessment of ENoG and BR was useful for evaluating the clinical severity of peripheral facial nerve palsy.