Different Laser Frequencies on Neuropathic Outcomes in Patients With Bell's Palsy

the laser irradiation will be deactivated in the sham laser device by its manufacturer, but its visual light and acoustic functions maintained. The output power of the sham laser's infrared light will be zero mW, will be applied over the eight points over the face

Low-Level Laser Therapy (LLLT) for 5 min over eight points over the face, with the laser probe in direct contact with the superficial roots of the facial nerve. The parameters will be used wavelength of 808 nm (Polaris HP, Astar, Bielsko-Biała, Poland) and 980 nm (TheraLASER max, TheraMarkt, Germany), frequency of 1 kilohertz, the duty cycle of 80%, and energy density of 10 J/cm'. During each session, the total energy will be delivered to the patient are 1440 J per session (8 treatment points × 180 J per point; 3 W average power over a 6 cm² applicator, 60 s per point).

gallium arsenide diode laser (BTL-5000 laser) will be used with infrared probes of 830 nm wavelength and 100 mW output power, average energy density of 10 J/em?, a frequency of 1 kilohertz, and a duty cycle of 80 %. In all cases, the laser will be in direct contact with the superficial roots of the facial nerve on the affected side and will be applied for 2 min and 5 s per point for 8 points with a total energy of 1440 J per session (8 treatment points × 180 J per point; 3 W average power over a 6 cm² applicator, 60 s per point)

High intensity laser therapy treatment with pulsed neodymium doped: yttrium aluminum garnet laser. The apparatus provided the following options: pulsed emission (1,064 nm), very high peak powers (3 kW), high levels of fluency (energy density) (810-1,780 mJ/cm), brief duration (120-150 Ms), low frequency (10-40 Hertz), and a duty cycle of approximately 0.1 %. High intensity laser therapy will be applied with contact and perpendicular to the superficial roots of the facial nerve of the affected side. The time of application will be 7 s/per point with an energy density of 10 J/em'. The total energy delivered to the patient during one session will be 1440 J per session (8 treatment points × 180 J per point; 3 W average power over a 6 cm² applicator, 60 s per point). The device calculates the number of pulses, energy received for each session, and the total energy delivered to the patient during the treatment session

Patients in all treatment groups received the same standardized rehabilitation programme consisting of facial massage, mirror exercises, and resisted facial and neck exercise