Clinical Definition

Bell’s palsy is a paralysis of the facial muscles caused by damage such as swelling, compression, or inflammation to the seventh cranial nerve.

An electromyography (EMG) can detect the presence and extent of nerve damage and may also help to predict the rate of recovery. A magnetic resonance imaging (MRI) test can rule out other causes for the facial nerve dysfunction.

In Our Own Words

Bell’s palsy is temporary paralysis of facial muscles in which a person cannot control the muscles or expressions on one side of the face. One side of the face will appear droopy, and this can take a toll psychologically on affected individuals. It is caused from damage to  the 7th cranial nerve, or the facial nerve, and the type of damage is thought to be consistent with inflammation or reaction to a viral infection. The exact cause has yet to be pinned down definitively. Facial nerve damage may be isolated or part of an underlying condition such as Lyme disease.

Imaging with contrast-enhanced CT or gadolinium-enhanced MRI is done in certain cases, such as slow progression beyond 3 weeks or no improvement after 4 months. Most cases heal on their own after a couple of weeks to a few months, but in some cases will be treated with drugs such as corticosteroids or antiviral medications. An electromyography (EMG) can detect the presence and extent of nerve damage and may also help to predict the rate of recovery.