Bell's Palsey Nerve DiagramBell’s palsy affects a nerve called the facial nerve , also called the cranial nerve VII, resulting in muscle weakness on one side of the face. The nerve covers almost all the muscles of the face, including the eyes, the mouth, the forehead, and the back of the head (Occiput). It was named after the Scottish anatomist, Sir Charles Bell.

Your Odds of Bell’s Palsey

Bell’s palsy affects 40,000 people a year. It is less common before the age of 15 and after the age of 60. 70% to 80% of patients suffering from Bell’s palsy recover completely in 1 to 3 months. 61% have complete palsy (paralysis). 94% have partial palsy, and 29% exhibit lifelong residual weakness in the muscles of the face. Moreover, in 55% of the cases, the deficit is moderate to severe.

The facial nerve exits the brain and travels through a narrow bony canal in the skull, underneath the ear, and branches out to the muscles of the forehead, the eye, the tear gland, the mouth, the saliva gland, the tongue, the neck ,and the muscles in the back of the head. The functions of the facial nerve are to control eye blinking, and facial expressions, such as smiling and frowning. It also influences tearing, salivation, and taste. When the facial nerve is disrupted, facial muscle weakness and paralysis occur.

Inflammation is Our Enemy

The cause of Bell’s palsy is unknown. There are several theories that have been researched and have strong evidence that could be the causative factor. Studies done after autopsy on patients with Bell’s palsy showed congestion of the facial nerve with inflammatory cells in the bony canal, indicating an inflammatory cause. It shows that Bell’s palsy arises from compression of the facial nerve in the bony canal. In biopsy studies, infiltration of inflammatory cells were also found in the nerve. Inflammatory cells were found in all patients suffering from Bell’s palsy.

Other Underlying Causes

All the studies found demyelination – the deterioration of the fat layer around the nerve. Other studies show there is a link between Bell’s palsy and viral infections, such as cold sores, chicken pox, shingle, mononucleosis, respiratory illnesses, mumps, flu, and hand- foot-and-mouth disease. The belief is that the re-activation of the herpes virus causes inflammation and demyelination of the facial nerve. Hence, inflammation which compresses the facial nerve within its narrow canal is the most likely cause of the condition so far.

The clinical symptoms of Bell’s palsy are weakness and complete paralysis of all the muscles on one side of the face. The eyelids do not close and the lower lip sags. Eye becomes irritated from lack of lubrication and constant exposure to the atmosphere. Tear production decreases, however the eye appears to tear excessively due to the loss of the eyelid’s control, which allows tears to spill freely from the eye. Some of the other symptoms are discussed above, as well.

How Physical Therapy Can Help

Steroid treatments complemented with physical therapy provide better and faster recovery. The goals are to decrease the inflammation to take off the pressure on the nerve and to prevent demyelination. An additional goal is to decrease pain and regain the function of the affected muscles. Physical therapy involves the use of modalities such as the use of a TENS unit, short wave diathermy, electrical stimulation, and ultrasound to decrease pain and discomfort.

Electrical stimulation is also used to facilitate re-innervation of the nerve after demyelination has occurred. Proprioceptive Neuromuscular Facilitation (PNF) is used to reeducate the affected muscles to regain their functions. Massage and stretches are used to treat muscle tightness and contractures. Acupuncture seems to be an effective therapy, but there is insufficient evidence to support its efficacy and safety.

Call STARS physical Therapy if you have any questions or are seeking physical therapy treatment for Bell’s palsy.

by Raj Issuree, MPT


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