Bell's Palsy With a Duration of Greater Than 8 Weeks Treated With Multiwave Locked System Intervention

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.

EMG is an electrophysiologic measures that indirectly quantify facial nerve function by recording motor unit action potentials (MUAPs) in the muscle of Musculus depressor angulli oris, Frontalis muscle and Orbicularis oris. MUAPs are the spikes in electrical activity generated when a motor unit fires. A motor unit consists of a motor neuron and the corresponding muscle fibers innervated by the neuron.

The blink reflex test is to measures the facial nerve since the blink reflex delivers information on facial nerve function with normal trigeminal function. Blink reflex testing involves electrical stimulation of the supraorbital nerve on the affected side combined with a 2-channel simultaneous sEMG recording from both orbicularis oculi muscles. The exit of the supraorbital nerve in the supraorbital foramen is palpated on the rim of the orbit. Stimulation with 10-20 mA and 0.2 ms duration is used to produce a constant reflex. In blink reflex testing, two responses, R1 and R2, are analyzed. R1 is the fast ipsilateral response of the orbicularis oculi muscle with a latency of about 10-12 ms. The second bilateral response R2 has a latency of about 30-41 ms.

The R2 latency differences between both sides higher than 5-8 ms is considered pathologic.