February 1, 2017

Dysarthria is a motor-speech disorder that results in unclear speech. This inability to speak clearly is because of weakness, slowness, or lack of coordination in the muscles of the mouth, voice, and lungs.

Dysarthria is typically the result of some form of damage to the brain or nervous system, such as from a traumatic brain injury, stroke, tumor, or degenerative disease such as multiple sclerosis, amyotrophic lateral sclerosis (ALS), or Parkinson’s disease. It can occur at birth, such as from cerebral palsy, but more commonly affects older adults. It is a motor speech disorder, meaning that a person with dysarthria experiences difficulty pronouncing words clearly due to impairment at the neurological and/or muscular levels. This is in contrast to aphasia, which affects the parts of the brain responsible for understanding and producing language.

Speech is the ability to use the diaphragm, lungs, vocal cords, soft palate, hard palate, tongue, teeth, and lips to produce the sounds necessary to communicate orally. Dysarthria is one type of speech disorder.

Language is the ability to understand, combine, and manipulate parts of speech, words, phrases, sentences, and narratives in order to communicate either aloud or in writing. Aphasia is an example of a language disorder.

The type and severity of dysarthria depend on which area of the nervous system is affected. Dysarthria can be a mild annoyance, or it can have a devastating effect on a person’s ability to make him or herself understood.

Types of Dysarthria

  • Ataxic dysarthria can cause poor coordination of the speech muscles meaning that speech and volume is slow, erratic and irregular. Speech maybe explosive and extra stress may be put on syllables.
  • Flaccid dysarthria can cause a breathy voice that is often nasal in quality (because of poor control of the soft palate). There is often an obvious paralysis or weakness of the facial muscles.
  • Spastic dysarthria can cause a very slow, indistinct, monotone voice, and at times it may seem strained with some sounds being difficult to articulate.
  • Hyperkinetic dysarthria presents with a harsh, strained voice.
  • Hypokinetic dysarthria presents with a hoarse voice and low volume.
  • A Mixed dysarthria can have a mix of the symptoms mentioned above, and will depend on the type of neuron damage as to whether speech is more harsh or breathy.


Spasticity, largely resulting in weakness of the –

  • tongue
  • lips
  • facial muscles
  • pharynx and larynx.
  • Reduced palatal elevation can lead to hypernasal voice quality. Reduced breath support can lead to reduced volume or breathy voice quality.

Single Injury – Dysarthria is caused by damage to the brain. This may occur at birth, as in cerebral palsy or muscular dystrophy, or may occur later in life due to one of many different conditions that involve the nervous system, including –

  • Head injury or trauma to the face or neck
  • Traumatic brain injury
  • Stroke
  • Surgery involving the head, face, neck, or lungs
  • Cerebral palsy

Degenerative Conditions – A degenerative condition is one which becomes more severe over time. In the case of degenerative diseases and conditions, dysarthria will worsen over time as the result of ongoing damage to the brain, nerves, or muscles involved in producing speech. Examples include:

  • Muscular dystrophy
  • Brain tumor
  • Guillain-Barre syndrome
  • Myasthenia gravis
  • Multiple sclerosis
  • Huntington’s disease
  • Parkinson’s disease
  • Amyotrophic lateral sclerosis (ALS, also called Lou Gehrig’s disease)
  • Dementia

Temporary Causes – A person may temporarily experience symptoms of dysarthria as the result of a reversible condition. This can include –

  • Ill-fitting dentures
  • Drug use or alcohol intoxication
  • Sedation
  • Side effects of medications that act on the central nervous system, such as narcotics, phenytoin, or carbamazepine

Risk Factors

These factors increase your chance of developing dysarthria –

  • Being at high risk for stroke
  • Having a degenerative brain disease
  • Abusing alcohol or drugs
  • Being older and having poor health


A person with dysarthria may demonstrate the following speech characteristics –

  • “Slurred,” “choppy,” or “mumbled” speech that may be difficult to understand
  • Slow rate of speech
  • Rapid rate of speech with a “mumbling” quality
  • Limited tongue, lip, and jaw movement
  • Abnormal pitch and rhythm when speaking
  • Changes in voice quality, such as hoarse or breathy voice or speech that sounds “nasal” or “stuffy”

Since dysarthria is the result of an underlying injury or condition, it is often accompanied by other signs and symptoms of damage to the speech system. Common conditions that are distinct from dysarthria but may be seen alongside it include:

  • Dysphagia – Dysphagia is difficulty safely chewing or swallowing food and drink. Since the mouth and throat are involved with chewing as swallowing as well as speech, injuries or conditions that impair speech often result in dysphagia as well.
  • Drooling – Similarly, impaired control of the mouth – particularly the cheeks, tongue, and lips – can lead to difficulty containing and swallowing saliva.
  • Aphasia – If dysarthria is caused by damage to the parts of the brain that control the movement of the speech system, it is possible that the damage may also affect the parts of the brain associated with understanding language (receptive aphasia) and/or producing language (expressive aphasia).


  • Social difficulty – Communication problems may affect the relationships with family and friends and make social situations challenging.
  • 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


Developmental and Rehabilitative Therapy – Speech therapy for dysarthria centers on addressing three basic areas to improve overall success of communication: the speaker, the listener, and the communication environment.

Therapy for Degenerative Conditions – When dysarthria is caused by a degenerative condition, such as amyotrophic lateral sclerosis (ALS) or Parkinson’s disease, treatment plans and approaches may need to take into account not only the individual’s current symptoms, but also how the disease may affect communication in the future. This may mean planning for a time when a person’s speech is very difficult to understand.

Voice Banking and Communication Supports – In the past, communication supports such as text, pictures, and technology were believed to be a “last resort” approach, such as for people with ALS who were completely unable to speak. In recent years, however, it has become well understood that communication supports are a reasonable and extremely helpful approach whenever anyone’s oral speech is insufficient to meet his or her communication needs – at any time or in any situation.


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