Dysarthria is a condition in which the muscles you use for speech are weak or you have difficulty controlling them. Dysarthria often is characterized by slurred or slow speech that can be difficult to understand.

Common causes of dysarthria include nervous system (neurological) disorders such as stroke, brain injury, brain tumors, and conditions that cause facial paralysis or tongue or throat muscle weakness. Certain medications also can cause dysarthria.

Dysarthria treatment is directed at treating the underlying cause of your condition when possible, which may improve your speech. You may have speech therapy to help improve speech. For dysarthria caused by prescription medications, changing or discontinuing the medications may help.


Signs and symptoms of dysarthria vary, depending on the underlying cause and the type of dysarthria, and may include:

  • Slurred speech
  • Slow speech
  • Inability to speak louder than a whisper or speaking too loudly
  • Rapid speech that is difficult to understand
  • Nasal, raspy or strained voice
  • Uneven or abnormal speech rhythm
  • Uneven speech volume
  • Monotone speech
  • Difficulty moving your tongue or facial muscles

When to see a doctor

Dysarthria can be a sign of a serious condition. See your doctor if you have sudden or unexplained changes in your ability to speak.


In dysarthria, you may have difficulty moving the muscles in your mouth, face or upper respiratory system that control speech. Conditions that may result in dysarthria include:

  • Amyotrophic lateral sclerosis (ALS, or Lou Gehrig's disease)
  • Brain injury
  • Brain tumor
  • Cerebral palsy
  • Guillain-Barre syndrome
  • Head injury
  • Huntington's disease
  • Lyme disease
  • Multiple sclerosis
  • Muscular dystrophy
  • Myasthenia gravis
  • Parkinson's disease
  • Stroke
  • Wilson's disease

Some medications, such as narcotics or sedatives, also can cause dysarthria.


Because of the communication problems dysarthria causes, complications can include:

  • Social difficulty. Communication problems may affect your relationships with family and friends and make social situations challenging.
  • Depression. In some people, dysarthria may lead to social isolation and depression.

May 18, 2018
  1. Dysarthria. American Speech-Language-Hearing Association. https://www.asha.org/public/speech/disorders/dysarthria/. Accessed April 12, 2018.
  2. Maitin IB, et al. eds. Current Diagnosis & Treatment: Physical Medicine & Rehabilitation. New York, NY: The McGraw-Hill Companies; 2014. http://accessmedicine.com. Accessed Feb. 18, 2015.
  3. Neurological diagnostic tests and procedures fact sheet. National Institute of Neurological Disorders and Stroke. http://www.ninds.nih.gov/disorders/misc/diagnostic_tests.htm. Accessed April 12, 2018.
  4. Drugs that cause dysarthria. Micromedex 2.0 Healthcare Series. http://www.micromedexsolutions.com. Accessed Feb. 18, 2015.
  5. Dysarthria in adults. American Speech-Language Hearing Association. https://www.asha.org/PRPPrintTemplate.aspx?folderid=8589943481. Accessed April 12, 2018.
  6. Signs and symptoms of untreated Lyme disease. Centers for Disease Control and Prevention. https://www.cdc.gov/lyme/signs_symptoms/index.html. Accessed April 12, 2018.