What is Dysarthria?
Dysarthria is caused by muscle weakness or the inability to control the muscles related to speech. Speech appears slurred or unintelligible to the listener. Dysarthria can mildly affect the way speech is understood or it can be quite severe, making it difficult to understand one’s speech.
Dysarthria can also impact the coordination of movement that involves respiration, phonation, resonance, and prosody. These are all components that contribute to the way that one speaks and communicates oral messages.
Respiration - the air we breathe in and out; the power for speech production
Phonation - the air we produce that vibrates the vocal cords
Resonance - the air shaped by the oral and nasal cavities
Prosody - the rhythm and intonation of speech
Causes of Dysarthria
Dysarthria causes speech muscles (sometimes called articulators - lips, tongue, cheeks, etc.) to be weak, in addition to difficulties with the components mentioned above. This is secondary to neuromuscular disturbance/damage to the brain. Dysarthria does not occur alone, meaning an individual has dysarthria as a result of something. It can be can be congenital (present at birth) or occur following an injury or illness. Some common causes include (but are not limited to):
Brain injury or tumor
Multiple sclerosis (MS)
Amyotrophic lateral sclerosis (ALS)
7 Types of Dysarthria and Speech Characteristics
Characteristics can range in severity and vary in cause depending on the type of dysarthria. Dysarthrias are often classified into 7 different types:
Treatment for Dysarthria
If you or a loved one is interested in receiving treatment for dysarthria, a consultation, evaluation, and treatment from a speech-language pathologist (SLP) is the most general first course of action. You may consult with your doctor about a referral to an SLP if you are concerned. Depending on the dysarthria type/severity and co-occurring disorders or difficulties, service delivery and intensity of services can vary. It may be appropriate for treatment to include other methods of communication, such as introducing an augmentative and alternative communication (AAC) system. According to ASHA, common treatment can also focus on:
Decreasing rate of speech
Increasing breath support to sound louder
Improving muscle strength of articulators
Increasing speech clarity
Dysarthria vs. Apraxia vs. Speech Sound Disorders
Dysarthria and apraxia are both motor speech disorders.
Dysarthria is caused by muscle weakness or the inability to control the speech muscles related to speech. The “plan” from the brain is correct, but the muscles aren’t able to follow the plan.
Apraxia is caused by the brain’s inability to create a solid “plan” to tell the muscles related to speech how to produce correct speech sounds. The muscles are able to follow the plan, but the plan is incorrect.
It is important to note that some individuals may have neurological damage that may cause both symptoms of apraxia and dysarthria.
Speech sound disorders related to articulation and phonology are more common in children versus childhood apraxia of speech (AOS) and dysarthria. There is a natural development of an individual’s ability to master articulation and reduce phonological patterns (e.g. an individual is able to produce the /b/ sound before the /r/ sound), but individuals with childhood AOS do not master the production of speech sounds following natural developmental patterns. Children with just speech sound disorders do not have muscle weakness in their articulators or the inability to control the speech muscles related to speech.
If you or a loved one has been diagnosed with or suspected to have dysarthria, we hope that this resource was helpful. Strategies like communicating in quiet environments, modifying questions to yes/no responses if something is unclear, avoiding filling in words or sentences for the person, and looking at the person when they are speaking, are all positive strategies that can be used when speaking with someone with dysarthria.
Additionally, feel free to check out the evidence-based articles and links below that also dive into the treatment and classification of dysarthrias.