Dysarthria: what it is, causes, symptoms and treatment

The NHS describes dysarthria as difficulty speaking because the muscles you use for speech are weak. It is a problem with the physical act of speaking rather than with language itself.

Headway explains that dysarthria occurs when there is damage to parts of the nervous system involved in the control of muscles used for speech, or when injury or weakness more directly affects the muscles. It results in reduced control and clarity of speech. When dysarthria occurs on its own, a person's ability to understand language and construct sentences is intact, although in practice there are often elements of both aphasia and dysarthria.

The NHS says the main symptom of dysarthria is unclear speech, which can make it difficult to make yourself understood. Speech may be only slightly unclear, or you may not be able to speak clearly at all. Being stressed or tired may make symptoms worse.

• Difficulty moving your mouth, tongue or lips.

• Slurred or slow speech.

• Difficulty controlling the volume of your voice, so you talk too loudly or too quietly.

• A change in your voice, making it nasal, strained or monotone.

• Hesitating a lot when talking, or speaking in short bursts instead of full sentences.

• Headway adds problems controlling the flow of air from the lungs when speaking and difficulty varying the tone of speech.

The NHS says dysarthria is usually caused by damage to the brain or conditions that affect the nervous system, and that it can happen at any age. It can also be a side effect of certain medicines, such as some medicines to treat epilepsy.

Dysarthria is often confused with other speech and language problems. The NHS says it is not the same as dysphasia, also called aphasia, which is where you have difficulty understanding words or putting them together in a sentence, although you can have both conditions at the same time.

Headway describes two main speech disorders after brain injury: dysarthria and dyspraxia of speech. In dyspraxia of speech, injury to areas of the brain responsible for conscious movement makes it hard to say what you are consciously thinking about saying, although some people may speak normally when not thinking about it.

The NHS says that if you have dysarthria you will usually be referred to a speech and language therapist, who will offer therapy to help your speech and communication. The therapy depends on the cause of your dysarthria and how severe it is.

The NHS says speech and language therapy may include exercises to strengthen the muscles used for speech, strategies to make your speech easier to understand, such as slowing down when you talk, and communication aids such as an alphabet board or a voice amplifier. It adds that some people may find therapy does not help their symptoms, or that their speech may get worse as their condition progresses, in which case therapy may focus on helping communication in other ways.

Headway says recovery depends on the severity of the initial brain injury and that people respond differently. In severe cases a person may be unable to achieve recognisable speech and may benefit from an augmentative aid to communication.

Parkinson's UK explains that in Parkinson's, changes in the brain make movements slower, smaller and less forceful, and that rigidity can also affect communication. It says people may find their speech sounds too quiet or unclear, or that they have to slow down to be understood. These symptoms are sometimes called hypokinetic dysarthria.

Parkinson's UK says a quieter, softer, breathier voice is called hypophonia, and that people may not realise they are talking more quietly. It says that if you are worried your voice has become quieter, talk to your specialist or Parkinson's nurse, who may refer you to a speech and language therapist.

The NHS says to call 999 if somebody's face droops on one side (the mouth or eye may have drooped), they cannot lift up both arms and keep them there, or they have difficulty speaking, with speech that may be slurred or garbled. These can be signs of a stroke, which is a medical emergency and usually comes on suddenly. Do not drive yourself to A&E.

The NHS says to see a GP if you have noticed gradual changes to your or your child's speech and you are worried. They will examine you and may refer you to a specialist for further tests.

Headway and Parkinson's UK suggest that speech and language therapists can assess dysarthria and recommend exercises, strategies and aids. The NHS points to Headway for communication problems after brain injury and to the Stroke Association for communication tools.

The NHS lists slowing down when you speak and using aids such as an alphabet board or voice amplifier. Parkinson's UK adds that apps can help check how loud your voice is, and that recording yourself on your phone and listening back can show whether your volume is too quiet. If you are often asked to repeat yourself, your voice might be too quiet.

On the NHS, a GP can examine you and refer you to a specialist or to NHS speech and language therapy. People with conditions such as Parkinson's disease, stroke or motor neurone disease are usually referred by their specialist team. Waiting times for therapy vary across the UK.

Some people also arrange private speech and language therapy for faster access or more frequent sessions. The therapy approaches described by the NHS, Headway and Parkinson's UK are broadly the same, and it is sensible to let your NHS team know if you start private therapy.