The mouth can be involved in several neurological disorders. The nerves that innervate the muscles of the mouth can be affected by a variety of processes, occurring anywhere along their paths, or in the motor control centers in the brain. Diseases that affect the muscles of the mouth can be part of a systemic illness--one that affects the entire body, or an isolated condition.
Facial Nerve Palsy
The facial nerve, or seventh cranial nerve, supplies the muscles of facial expression. It also transmits the sensation of taste from part of the tongue. Bell's palsy causes paralysis of the muscles on one side of the face. The affected person will have a lopsided smile and won't be able to puff out his cheek on that side. Facial appearance can be drastically changed. It may be difficult to chew, swallow or articulate properly, and the person might drool. The sense of taste is impaired. Bell's palsy usually gets better over time on its own, though sometimes it can recur.
Hypoglossal Nerve Injury
The hypoglossal nerve, or the twelfth cranial nerve, controls tongue movements. Damage to this nerve can lead to paralysis of one-half the tongue, causing the tongue to deviate towards the paralyzed side. As Merck.com explains, the nerve can be damaged by tumors at the base of the brain, infection, strokes and degenerative diseases that affect motor neurons such as amyotrophic lateral sclerosis, or ALS. Symptoms of tongue paralysis include difficulty chewing, swallowing and speaking.
Melkersson-Rosenthal Syndrome
Melkersson-Rosenthal syndrome is a rare condition in which facial paralysis comes and goes along with swelling of the face and lips. The tongue becomes furrowed. This condition starts during childhood or the teen years. It may be associated with Crohn's disease or sarcoidosis, an autoimmune disease, as explained by the National Institute of Neurological Disorders and Stroke. Treatment is aimed mainly at reducing the swelling, which can lead to permanently cracked, fissured and discolored lips.
Oromandibular Dystonia
Oromandibular dystonia is a condition that usually starts after the age of 40. Sometimes, it's an isolated neurological problem, other times, it's part of a disease such as Wilson's disease, which also causes psychiatric and liver problems. Symptoms include prolonged contractions of the muscles of the face, jaw and tongue. The affected person may not be able to open his mouth. He may have difficulty eating or speaking. As the National Institute for Neurological Disorders and Stroke explains, treatments include muscle relaxants, such as Valium and Botox injections, which are intended to paralyze enough of the muscle to allow normal functioning. Sensory stimulation, such as touching the skin in a particular spot, can often cause the muscles to relax. Response to this technique is highly individual, and each person needs to find the spot that might work for him. Speech therapy and relaxation techniques are also helpful.
References
- Merck.com: Hypoglossal Nerve Disordes
- National Institute of Neurological Disorders and Stroke: Melkersson-Rosenthal Syndrome
- Dystonia-Foundation.org: Oromandibular Dystonia
- "Adams and Victor's Principles of Neurology"; Maurice Victor and Allan Ropper; 2001
