What are the causes of dysarthria (slurred speech)?

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Last updated: April 21, 2025View editorial policy

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From the Guidelines

Slurred speech, or dysarthria, can be caused by various conditions affecting the muscles and nerves involved in speech production, including stroke, neurological disorders, brain injuries, certain medications, and structural issues, and prompt medical evaluation is essential for early diagnosis and effective treatment. The causes of slurred speech can be categorized into several groups, including:

  • Neurological disorders, such as Parkinson's disease, multiple sclerosis, or ALS, which affect nerve pathways and can lead to dysarthria 1
  • Brain injuries from trauma, which can disrupt the complex coordination between the brain, nerves, and muscles needed for clear speech production 1
  • Certain medications, such as sedatives, antipsychotics, or anticonvulsants, which can affect the muscles and nerves involved in speech production 1
  • Structural issues, such as dental problems or oral surgeries, which can affect the mouth, tongue, or throat and contribute to slurred speech 1
  • Transient conditions, such as extreme fatigue or stress, which can cause temporary disruption to speech production 1 It is essential to seek prompt medical evaluation if experiencing persistent slurred speech without a known cause, as early diagnosis can lead to more effective treatment and improved outcomes 1. The underlying mechanism of slurred speech involves disruption to the complex coordination between the brain, nerves, and muscles needed for clear speech production, affecting articulation, rhythm, or voice quality 1. Medical emergencies, such as stroke or severe allergic reactions, can cause sudden slurring and require immediate medical attention 1. In summary, slurred speech can be caused by a variety of conditions, and prompt medical evaluation is essential for early diagnosis and effective treatment.

From the Research

Causes of Slurred Speech

  • Neurological disorders such as stroke, traumatic brain injury, Parkinson's disease, and multiple sclerosis can cause slurred speech 2, 3, 4
  • These conditions can affect the brain's ability to control muscle movements, including those involved in speech production
  • Studies have shown that patients with these conditions often experience mobility disorders, balance problems, and participation restrictions, which can contribute to slurred speech 4
  • Additionally, certain medications, such as statins, may have neuroprotective effects and potentially impact speech production, although the mechanism of this effect is not fully understood 5
  • Psychological factors, including depression, can also affect neurological conditions and potentially contribute to slurred speech 2, 6

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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