Answer:
The most common type of facial paralysis is idiopathic, i.e. bell’s palsy. The incidence is 1 in 60 persons in a lifetime. The onset is abrupt, usually over 48 hours. About 80% of patients recover within a few weeks to months. Signs are intact forehead, loss of corneal sensation, miosis, loss of tearing, deviation of the tongue, and loss of taste papilla. EMG may be helpful in that evidence of denervation at 10 days may indicate a prolonged recovery phase. The presence of incomplete paralysis at 1 week is the most favorable prognostic sign. Treatment is protection of the eye during sleep. A course of prednisone begining at 60 or 80 mg daily for 5 days followed by a 5 day taper may be beneficial. There are many other causes of facial paralysis. Tumors usually cause paralysis over a longer time period. Bilateral paralysis occurs in acute inflammatory conditions. All forms of nuclear or peripheral nerve palsy must be distinguished from supranuclear palsy. In the latter, the frontalis and orbicularis muscles are involved less than those of the lower face since the upper facial muscles are innervated from both motor cortices, and the lower facial muscles are innervated only by the opposite motor cortex.