Updated: Jul 14, 2019
Dysarthria is a motor speech disorder which results in speech being less clear (intelligible). It occurs when the brain is affected in one or more of the areas involved in the innervation and control of the muscles involved in speech. Dysarthria varies in its severity and there are different therapy options available.
How can speech change?
The following changes can occur in dysarthria:
Reduced volume of speech - this can make it difficult to hear an individual
Reduced pitch range - this can affect the higher or lower pitches or both. It can affect individuals’ marking intonation patterns, resulting in speech being monotone.
Imprecise articulation of sounds - for example, people can have difficulty making particular sounds if the tongue or lips muscles are weak.
Changes in nasality - speech can become either hyper or hyponasal.
Changes in the speed of speech - speech may become slow or ‘rushed’
People’s speech may change in only one way (e.g. reduced volume) or in multiple ways.
Dysarthria varies severity. Some people's speech will be less clear but remains understandable to others. For some people, their dysarthria will be so severe that people cannot understand anything the person is saying; the term anarthria can be used to refer to a severe dysarthria.
Why do people get dysarthria?
Dysarthria can result from a variety of conditions including:
Motor neuron disease
Brain tumour/ metastases
People can also have a temporary dysarthria from drinking a large quantity of alcohol.
The different types of dysarthria
There are the following types of dysarthria:
These different types are due to the different brain areas affected.
For example, when the basal ganglia is affected, people have hypokinetic dysarthria; this is the type that occurs in people with Parkinson’s disease or in people who have had a stroke or brain injury affecting the basal ganglia.
Ataxic dysarthria is due to the cerebellum being affected.
People with Motor Neuron Disease (MND) may have flaccid, spastic or a mixed flaccid-spastic dysarthria.
Different types of dysarthria have different clinical presentations. The individual's dysathria presentation and how it is impacting them, along with their prognosis, will be considered when deciding the best therapy input.
In people with a progressive condition, such as Parkinson's disease, motor neurone disease, multiple sclerosis, and Huntington disease, their dysarthria is likely to get worse worth as their condition progresses. However, people can still benefit from having therapy by implementing strategies to promote their speech to be as intelligible as possible and developing use of alternative strategies to support their expression (see below for a brief overview of AAC).
People who have dysarthria secondary to a stroke would be expected to make improvements and it may resolve; the exception would be if an individual’s cognitive abilities have been so severely impacted that it affects their ability to engage in therapy, use strategies or respond to feedback.
Speech and Language Therapy for Dysarthria
There are a variety of therapy options for people with dysarthria.
In cases of mild to moderate dysarthria, people may need to practise simple strategies such as slowing down the rate of their speech and using diaphragmatic breathing to support speaking louder. One widely used therapy approach is Lee Silverman Voice Treatment (LSVT).
Some people need external prompts to help them slow down their speech such as using a pacing board; for example, tapping on along a piece of a paper to set the pace of their speech.
In more severe cases, people may benefit from using augmentative and alternative communication (AAC) devices. There are many different types of AAC. Examples of low tech include writing using a pen and paper or using a communication book. A communication book can have different options for a person to choose from. For example, having different drink options listed for an individual to point to.
High tech devices are similar but use technology so instead of writing with pen and paper, they may use a device. Instead of using a communication book, they may use an app on a tablet.
All AAC devices need to be trialled with a speech and language therapist to explore what is useful for the individual. Other factors impact the successful use of AAC such as a person's language abilities, cognitive abilities, their previous use of technology and whether the environment is supportive to them using that device.
In summary, dysarthria is a motor speech disorder which negatively impacts the intelligibility of people’s speech. It can happen in a variety of different conditions. There are different types of dysarthria depending on which brain area is affected. There are many different therapy approaches available to people with dysarthria; people should be supported by a speech and language therapist to explore what therapy is best for them.
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