neurologic disorders
Facial Nerve Palsy
Prognosis for Facial Nerve Palsy
In idiopathic facial nerve palsy, the extent of nerve damage determines outcome. If some function remains, full recovery typically occurs within several months. Nerve conduction studies and electromyography are done to help predict outcome. The likelihood of complete recovery after total paralysis is 90% if nerve branches in the face retain normal excitability to supramaximal electrical stimulation and is only about 20% if electrical excitability is absent. Regrowth of nerve fibers may be misdirected, innervating lower facial muscles with periocular fibers and vice versa. The result is contraction of unexpected muscles during voluntary facial movements (synkinesia) or crocodile tears during salivation. Chronic disuse of the facial muscles may lead to contractures. 