Causes

In a person with dysarthria, a nerve, brain, or muscle disorder makes it difficult to use or control the muscles of the mouth, tongue, larynx, or vocal cords, which make speech.

The muscles may be weak or completely paralyzed, or it may be difficult for the muscles to work together.

Dysarthria may be the result of brain damage due to:

• Brain tumor
• Dementia
• Stroke
• Traumatic brain injury

Dysarthria may result from damage to the nerves that supply the muscles that help you talk, or to the muscles themselves from:

• Face or neck trauma
• Surgery for head and neck cancer, such as partial or total removal of the tongue or voice box

Dysarthria may be caused by diseases that affect nerves and muscles (neuromuscular diseases):

• Cerebral palsy
• Multiple sclerosis
• Muscular dystrophy
• Myasthenia gravis
• Parkinson's disease

Other causes may include:

• Alcohol intoxication
• Poorly fitting dentures
• Side effects of medications that act on the central nervous system, such as narcotics, phenytoin, or carbamazepine

Symptoms

Depending on its cause, dysarthria may develop slowly or occur suddenly.

People with dysarthria have trouble making certain sounds or words.

Their speech is poorly pronounced (such as slurring), and the rhythm or speed of their speech changes. Other symptoms include:

• Sounding as though they are mumbling
• Speaking softly or in a whisper
• Speaking in a nasal or stuffy, hoarse, strained, or breathy voice

A person with dysarthria may also drool and have problems chewing or swallowing. It may be difficult to move the lips, tongue, or jaw.

Exams and Tests

The health care provider will take a medical history and perform a physical examination. Family and friends may need to help with the medical history.

The physician may perform a laryngoscopy. In this test, a flexible viewing tube called a laryngoscope is placed in the mouth and throat to view the voice box.

Tests that may be performed if the cause of the dysarthria is unknown include:

• Blood tests for toxins or vitamin levels
• Imaging tests, such as an MRI or CAT scan of the brain or neck
• Nerve conduction studies and electromyogram to check the electrical function of the nerves or muscles

Treatment

You may need to be referred to a speech and language therapist for testing and treatment. Special skills you may learn include:

• Safe chewing or swallowing techniques, if needed
• To avoid conversations when you are tired
• To repeat sounds over and over again so you can learn mouth movements
• To speak slowly, use a louder voice, and pause to make sure other people understand
• What to do when you feel frustrated while speaking

You can use many different devices or techniques to help with speech, such as:

• Computers to type out words
• Flip cards with words or symbols
• Special computer programs that allow you to create spoken words by typing words or clicking on symbols

It's important to maintain a relaxed, calm environment. Reduce noise, music, and other stimuli during communication.

A few surgical techniques may help people with ALS and dysarthria.

Outlook (Prognosis)

Depending on the cause of dysarthria, symptoms may improve, stay the same, or get worse slowly or quickly.

• Patients with amyotrophic lateral sclerosis (ALS or Lou Gehrig's disease) eventually lose the ability to speak.
• Few people with Parkinson's disease or multiple sclerosis lose the ability to speak.
• Dysarthria caused by medication or poorly fitting dentures can be reversed.
• Dysarthria caused by a stroke or brain injury will not get worse, and may improve.
• Dysarthria after surgery to the tongue or voice box should not get worse, and may improve with therapy. The severity of dysarthria depends on what type and how much tissue was removed.

Possible Complications

• Pneumonia caused by breathing in saliva or food
• Depression
• Low self-esteem
• Social problems

When to Contact a Medical Professional

Call your health care provider if you have:

• Chest pain, chills, fever, shortness of breath, or other symptoms of pneumonia
• Coughing or choking
• Difficulty speaking to or communicating with other people
• Feelings of sadness or depression

Prevention

There are no specific ways to prevent dysarthria. Preventing the cause, such as stroke, nerve injury, or other brain and nervous system problems is the best approach.

Alternative Names

Impairment of speech; Slurred speech; Speech disorders - dysarthria

References

Swanberg MM, Nasreddine ZS, Mendez MF, Cummings JL. Speech and language. In: Goetz CG, ed. Textbook of Clinical Neurology. 3rd ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 6.

Cohen SM, Elackattu A, Noordzij JP, Walsh MJ, Langmore SE. Palliative treatment of dysphonia and dysarthria. Otolaryngol Clin North Am. 2009;42:107-121.

Update Date: 4/26/2012

Reviewed by: Daniel B. Hoch, PhD, MD, Assistant Professor of Neurology, Harvard Medical School, Department of Neurology, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.