What is dysarthria?
Speech requires precise coordination of breathing, voice production (phonation), resonance, articulation and prosody (rhythm and melody). In dysarthria, damage to the brain, nerves or muscles weakens or disrupts one or more of these systems. Language and thinking are usually intact, which distinguishes dysarthria from aphasia (a language disorder) and from apraxia of speech (a motor planning disorder).
Symptoms
- Slurred, mumbled or imprecise speech.
- Slow or, less often, rapid speech that runs together.
- Speech that is too soft, too loud or monotone.
- Hoarse, breathy, strained or nasal-sounding voice.
- Difficulty controlling the pitch and volume.
- Drooling, difficulty chewing or swallowing (dysphagia), often coexisting.
- Rapid fatigue when speaking, and difficulty being understood by others.
Types of dysarthria
- Flaccid: weakness from damage to the peripheral nerves or muscle (for example bulbar palsy, myasthenia gravis).
- Spastic: stiffness from damage to upper motor neurons (stroke, cerebral palsy).
- Ataxic: poor coordination from cerebellar damage, giving irregular, “scanning” speech.
- Hypokinetic: reduced movement and volume, as in Parkinson’s disease.
- Hyperkinetic: involuntary movements, as in Huntington’s disease or dystonia.
- Mixed: combinations, as in ALS, multiple sclerosis and traumatic brain injury.
Causes
- Stroke and transient ischaemic attack.
- Traumatic brain injury and brain tumours.
- Neurodegenerative diseases: Parkinson’s disease, ALS (motor neurone disease), Huntington’s disease, multiple sclerosis.
- Cerebral palsy and other developmental conditions.
- Myasthenia gravis, muscular dystrophy and other neuromuscular diseases.
- Medicines and substances: sedatives, anticonvulsants, alcohol intoxication.
- Infections, surgery affecting the head, neck or brain.
How it is assessed
A doctor, often a neurologist, looks for the underlying cause with a neurological examination, brain imaging (CT, MRI), blood tests and other studies. A speech-language pathologist (SLP; logopeda in Spanish) assesses speech with standardised tasks: sustained vowels, repeated syllables, reading, conversation and intelligibility measures. They evaluate breathing, voice, resonance, articulation and swallowing, and consider the impact on daily life and communication partners.
Speech therapy
- Strengthening and coordination of speech muscles with exercises tailored to the type of dysarthria.
- Breath support and voice work: exercises to improve breath control, loudness and phonation (for example LSVT LOUD for Parkinson’s disease, an intensive voice-focused therapy).
- Articulation drills to improve precision of consonants and vowels.
- Pacing and rate control: slow speech, pausing and phrase chunking.
- Compensatory strategies: exaggerating articulation, speaking in short sentences, using gestures, writing and communication partner strategies.
- Augmentative and alternative communication (AAC): alphabet boards, text-to-speech apps and speech-generating devices for severe cases.
- Therapy should be started early, and intensity and practice matter.
Tips for speaking and for listeners
- For the speaker: reduce background noise, face your listener, take a breath before speaking, speak slowly and in short phrases, exaggerate sounds, stress key words and use gestures or writing when needed.
- For listeners: be patient, avoid finishing sentences, ask yes/no questions, repeat back what you understood, and keep eye contact.
- Rest when tired: dysarthria often worsens with fatigue.
- Practise the exercises given by your therapist daily.
Dysarthria in children
In children, dysarthria is commonly associated with cerebral palsy, brain injury or neuromuscular conditions. Early speech therapy supports speech development and communication; AAC may be introduced early so that the child can express themselves while speech develops. If a child’s speech is unclear for their age without an obvious cause, consider assessment of a speech sound disorder or apraxia. See selective mutism (Spanish) and stuttering (Spanish) for other speech conditions.
When to seek help
- Any sudden change in speech: emergency services.
- Gradual slurring, weakness of the voice or speech that is harder to understand.
- Difficulty swallowing, choking or drooling.
- Speech changes after a head injury, surgery or starting a new medicine.
- A child whose speech is difficult to understand compared with peers.
- Frustration, withdrawal or reduced participation because of speech difficulty.
Three common situations
Sudden slurred speech and facial droop: call emergency services immediately.
Quieter, monotone speech in someone with Parkinson’s disease: speech therapy such as LSVT LOUD can help voice and clarity.
Speech becoming gradually slurred over months with muscle weakness: see a neurologist and a speech therapist promptly.
Swallowing, safety and communication aids
Because the muscles of speech and swallowing overlap, many people with dysarthria also have dysphagia: coughing or choking on food or drink, a wet or gurgly voice after swallowing, or recurrent chest infections. A speech-language pathologist can assess swallowing and recommend safer textures and strategies. For people whose speech is hard to understand, communication aids range from low-tech alphabet charts and writing pads to tablets with text-to-speech apps and eye-gaze systems, and they can be used alongside speech rather than instead of it.
Key points to remember
Dysarthria is a speech muscle control problem with many possible causes. Sudden onset is an emergency. Speech therapy and communication strategies can improve intelligibility and quality of life. Our speech-language therapy team can assess and support you.
This guide is for general information and does not replace an assessment by your own doctor, speech-language pathologist or dietitian.
Questions about dysarthria
These answers are general information and do not replace an examination or individual medical advice.
What is the difference between dysarthria and aphasia?
Dysarthria affects the muscles used for speech; aphasia affects language itself (finding and understanding words).
Can dysarthria be cured?
It depends on the cause. Dysarthria after a stroke may improve; progressive conditions need ongoing management. Therapy improves clarity in many people.
Is slurred speech always a stroke?
No, but sudden slurred speech should be treated as an emergency until a stroke is ruled out.
What does a speech therapist do for dysarthria?
They assess the type and severity, and teach exercises and strategies for breathing, voice, articulation and pacing, and recommend communication aids.
Does dysarthria affect swallowing?
Often, since the same muscles are involved; a swallowing assessment is advisable.
Can children have dysarthria?
Yes, commonly in cerebral palsy and other neurological conditions.
Can speech therapy help in progressive conditions such as ALS or Parkinson’s?
Yes. Therapy can maintain clarity for longer, teach compensatory strategies, and plan for communication aids as the disease advances.
Sources
This guide is for general information and does not replace medical advice. How a problem is diagnosed and treated depends on your examination and medical history. If you think you have an emergency, contact your local emergency services.