Dysphonia: A Speech-Related Symptom of MS

Dysphonia is difficulty speaking due to a reduced control of the muscles of your lips, mouth, tongue, throat, and/or vocal cords.

In multiple sclerosis (MS), dysphonia often means trouble controlling the volume of speech, meaning speaking too softly to be heard or more loudly than is appropriate. Other examples of dysphonia include hoarseness, raspy speech, or a change in pitch when you try to talk.

Dysphonia Is One Form of Dysarthria

If you have MS or know someone who has it, you may be aware that there are many ways this disease can affect the ability to speak clearly. These speech problems, including dysphonia, are grouped under the term dysarthria—speech problems that arise from a reduced control of the muscles used in speech, often as a result of nerve damage. Dysarthria is different than aphasia (impairment of language)

Dysarthria affects nearly half of people with MS and is the most common disorder of communication in those with this disease. It’s usually mild; however, symptom severity reflects the extent of nerve damage, as well as the type of disease course (relapsing-remitting MS versus progressive MS).

MS-related dysarthria is most likely to affect your rate of speaking, the understandability of your speech, and its natural conversational flow.

Examples include:

• Slurred speech, with problems pronouncing words
• “Scanning” speech, in which you speak very slowly, with long pauses between words and even between syllables of a word 
• “Explosive” speech, with episodes of loud, rapid speech production

Cause of Speech Problems in MS

MS-related dysarthria typically results from nerve damage that weakens the muscles of your lower face, lips, tongue, and throat. Most commonly, the cause is multiple small areas of damage in either of the two large lobes of your brain or your brainstem, an area of nerves between your brain and your cervical (neck area) spinal cord.

Other forms of MS-related dysarthria are believed to result from myelin sheath damage within cerebellum, the part of the brain at the back of your skull.

Rarely, speech disturbances in MS result from aphasia, loss of ability to understand or express speech.

The Three Types of Dysarthria in MS

Doctors diagnose three different types of dysarthria in people with MS:

• Spastic dysarthria, mainly featuring muscle stiffness or tightness
• Ataxic dysarthria, mainly featuring loss of muscle movement control
• Mixed dysarthria, which combines features of both the spastic and ataxic types

Mixed dysarthria is most common in people with MS. This is because MS typically affects multiple areas of your nervous system. In mixed dysarthria, nerve damage may involve your brain’s white matter and/or cerebellum, your brainstem, and/or your spinal cord.

Besides neurologic signs like increased muscle tone or balance problems, there are voice signs that can clue you into the type of dysarthria present.

For instance, spastic dysarthria is characterized by voice features like:

• A harsh, strained voice quality
• A slow rate of speech
• Reduced loudness or mono-loudness

Ataxic dysarthria is characterized by the following voice features:

• A vocal tremor
• Dysrhythmic, rapid, and alternating movements of the tongue, lips, and jaw
• Scanning speech
• Excess and variable loudness

What Can Be Done to Improve Speech in MS?

A speech-language therapist can provide exercises to strengthen the muscles involved in speech or to improve your breathing by helping to relax them. In addition, a speech-language therapist can teach you techniques for slowing rapid speech, pausing properly between words, and pronouncing words clearly and correctly.

Dysarthria in MS rarely progresses to the point where a person is unable to speak. But if speaking becomes too difficult for a person, he or she may use an alternative form of communication like voice amplifiers or computer boards.

A Word From Verywell

While there is no cure yet, many people with MS live well because they are able to manage their symptoms effectively.

Unfortunately, no medications are available that directly help improve MS-related speech problems. However, medications that relieve symptoms such as muscle stiffness or tightness (spasticity) may provide some speech improvement.

Lastly, assistance with a speech therapist, even a few sessions, can do wonders for your (or your loved one's) speaking difficulty—and your confidence and quality of life.