In PBMT group, we choose 9 points on the affected face, include Mastoid, Preauricular, Temple, Frontalis muscle, Zygomatic muscle, Buccinator muscle, Masseter, Orbicularis oris and Depressor angulli oris. Based on clinical experience, we choose 7 acupoints, including LI4 (HeGu), LI11(QuChi), ST25 (TianShu), ST36 (ZuSanLi), SP6 (SanYinJiao), KI3 (TaiXi), LR3 (TaiChong). All the acupoint were applied bilaterally.

Laser divice directly contacts the points. All those points near the superficial roots of facial nerve. At each point, we treated for 1min, 1500 Hz, 50% laser intensity. And patients in PBMT group wore safety glasses to prevent eye damage during the laser sessions. All treatments were performed in the outpatient clinic by the same physician.

Patients in the control group received no intervention but were free to pursue therapies if desired.

Multiwave Locked System laser is a class IV NIR laser with two synchronized sources (905 nm with 75 W peak power, pulsed mode; 808 nm with power 1 W, continuous mode). Both laser beams were synchronized, the locked waves work with the range 1-2000 Hz.

The House-Brackmann facial nerve grading system (HB grading) is based on a 6-grade score that offers a gross evaluation of facial motor function and includes the evaluation of sequelae. The prognoses of patients with House- Brackmann grade I or grade II were considered good, and the prognoses of those with grade 3 or higher were considered poor.

The goal of the Electroneurography (ENoG) testing is to measure the amount of neural degradation that has occurred distal to the site of facial nerve injury by measuring the muscle response to an electrical stimulus. The testing of ENoG involves recording the compound muscle action potential (CAMP) of the mimetic muscles, including Orbicularis oculi, Frontalis muscle, Orbicularis oris and Zygomaticus muscle. ENoG is performed first on the healthy side of the face and then on the affected side. Nerve damage or nerve fiber degeneration leads to a decrease or loss of the CAMP. The amplitude of the CAMP on the affected side is compared to the CAMP of the healthy side and expressed as percent (amplitude of the paralyzed side divided by the amplitude of the normal side). A side difference of 30% or bigger is considered pathologic.

The Sunnybrook facial grading system (SB grading) is 13-items, self-reported questionnaire that used to evaluate the facial movement of patients. Among the overall 13 items of question, 3 items are resting symmetry, 5 items are symmetry of voluntary movement, and 5 items are synkinesis. Lower scores of Sunnybrook equate to greater severity of facial paralysis symptoms.