Facial paralysis is a condition frequently seen in otology and audiology clinics.
Its most common etiologies are idiopathic, trauma and infection. This article deals
with the pathophysiology of facial paralysis, diagnostic technique and treatment modalities
illustrated with case studies. The section on pathophysiology includes a discussion
of the classification of nerve injury: neuropraxia that may be associated with a compressional
injury, axonotmesis associated with an interruption of the myelin layer and axon and
neurotmesis involving a complete transection. Among diagnostic techniques, evoked
facial electromyography or electroneuronography and needle EMG are discussed and compared.
Needle EMG in particular is useful in cases with complete facial paralysis and an
evoked EMG reduction of 90% or more. Among patients with idiopathic facial paralysis
approximately 71% recover completely and approximately 16% remain with serious sequelae.
In terms of treatment, corticosteroids and antiviral medications may be used. Surgical
decompression may be used in selected cases to relieve intraneural pressure.
Facial paralysis - Bell's palsy - electromyography - electroneuronography - evoked
EMG - facial nerve - motor unit potential - neuropraxia - axonotmesis - neurotmesis
- blink reflex - fibrillation potentials
