George Krucik, MD, MBA
Multiple sclerosis is a progressive neurological disease caused by damage to neurons in the brain and spinal cord. The damage occurs to the outer layer of the neurons, which is called the myelin sheath. The exact cause is not fully understood, but doctors believe the body's immune system mistakenly attacks the myelin coating of these neurons, which damages the ability of the brain to communicate with the rest of the body. Multiple sclerosis can cause many symptoms, including symptoms in the tongue.
Patients with multiple sclerosis often experience muscle weakness in muscles that are controlled by damaged neurons. If the neurons controlling the tongue are damaged, weakness in the tongue may result. A study published in the January-February 2003 issue of the journal "Folia Phoniatrica et Logopaedica" found that tongue function was severely affected in a group of 77 multiple sclerosis patients.
Damage to the nerves controlling the tongue can also cause difficulty swallowing, which is known as dysphagia. Up to half of all multiple sclerosis patient develop dysphagia, according to the Multiple Sclerosis Foundation. Swallowing is a complex behavior that requires coordinating the movements of the tongue with the lips, jaw, cheek, facial muscles and soft palate. The tongue is responsible for moving food to the back of the throat after it has been chewed. Loss of coordination of the tongue and other facial muscles can make it very difficult for a patient with multiple sclerosis to swallow. Doctors can perform a test called a modified barium swallow to assess the activity of the tongue.
Because the tongue is also intricately involved in speaking, patients with MS often develop speech problems, such as slurred speech, reports MedlinePlus. More specifically, patients with multiple sclerosis often develop problems correctly articulating consonants, the study published in "Folia Phoniatrica et Logopaedica" explains. Additionally, the tongue control problems often lead to excessive harshness of the voice, difficulty speaking at an even speech rate, and correctly placing stress on syllables and words.