Understanding the features of posterior auricular muscle response in a facial nerve disease prototype

This study aims to compare and investigate the changes of posterior auricular muscle response (PAMR) following peripheral facial nerve palsy (PFP) with blink reflex (BR).

A total of 75 idiopathic PFP patients and age and sex-matched 38 healthy volunteers were included. Patients with PFP were classified into two groups including early (≤6 months) and late (>6 months) based on the duration of symptoms. Following clinical evaluation, PAMR and BR were recorded. A comparison was performed among the early PFP group (n=52), late PFP group (n=23) and healthy volunteers (n=38).

We obtained PAMR in 78.9% (n=30) of healthy volunteers, in 60.9% (n=14) of late and in only 38.5% (n=20) of early PFP patients (p=0.001). No habituation was observed following repeated stimuli. The mean latencies were 9.1±1.6, 10.9±1.9 and 12.3±2.0 msec., respectively (p=0.000). R1 and R2 latencies were longer in the early PFP group, compared to other groups (p=0.000).

Posterior auricular muscle response exhibits changes in a manner similar to R1 and R2 of BR in early and late PFP. The occurrence rate of PAMR seems to be lowest or its latency is prolonged in the early PFP.