Reference value of f-wave latency in the facial nerve based on human subjects.

PURPOSE: The aim of this study was to investigate an appropriate methodology to record F waves and establish the reference value of F-wave latency in the facial nerve, which provides an electrophysiological basis for facial nerve evaluation in clinical patients.

METHODS

One hundred fifty-eight healthy subjects were recruited and divided into seven groups based on their age. With percutaneous electrical nerve stimulation at the mastoid process, surface electrodes were placed onto the orbicularis oculi muscles bilaterally, and F-wave latency (Flat) and F-persistence in the facial nerve were measured.

RESULTS

The average latency was 30.65 ± 4.22 milliseconds among subjects under 10 years old; 28.17 ± 2.28 milliseconds among subjects 10 to 19 years of age; 27.97 ± 3.48 milliseconds among subjects 20 to 29 years old; 29.60 ± 1.78 milliseconds among subjects 30 to 39 years of age; 30.06 ± 1.94 milliseconds among subjects 40 to 49 years old; 30.52 ± 2.08 milliseconds among subjects 50 to 59 years of age, and 32.12 ± 3.0 milliseconds among subjects above 60 years old. According to this study, Flat in the facial nerve was associated with subjects' age. In addition, the average F-persistence of the facial nerve was 98.07%.

CONCLUSIONS

Flat showed a U-shaped distribution among subjects with increasing age. Among subjects younger than 10 years, Flat shortened with increasing age, but among subjects 10 to 29 years old, Flat did not change significantly and was the shortest among all groups. Among subjects older than 30 years, Flat became longer with increasing age, and the longest Flat was in subjects older than 60 years.