Dysarthria

Dysarthria is a motor speech disorder resulting from neurological injury, characterised by poor articulation (cf aphasia: disorder of the content of speech). Any of the speech subsystems (respiration, phonation, resonance, prosody, articulation and movements of jaw and tongue) can be affected.

Disarthic speech is due to some disorder in the nervous system, which in turn hinders control over, for example, tongue, throat, lips or lungs. Swallowing problems, dysphagia, are often present.

Cranial nerves that control these muscles include the facial nerve (VII), the glossopharyngeal nerve (IX), the vagus nerve (X), and the hypoglossal nerve (XII).

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Classification

Dysarthrias are classified in multiple ways based on the presentation of symptoms. Specific dysarthrias include spastic, flaccid, ataxic, unilateral upper motor neuron, and mixed dysarthria.

Causes

The reasons behind dysarthria can be many; among the diseases are stroke, ALS, Parkinson's disease, botulism, cranial nerve lesions, chorea, prion protein related diseases, and cerebral palsy. Dysarthria can also be an early symptom of stroke, and of other forms of traumatic brain injury. More common causes are intoxication and anesthesia, although these are transient. Another possibility is myasthenia gravis.

Treatment

The articulation problems that dysarthria causes can be treated together with a speech language pathologist using a range of techniques which sometimes includes strengthening the speech musculature. Augmentative and Alternative Communication (AAC) devices that make coping with dysarthria easier include speech synthesis software and text-based telephones.

References

• Haines, Duane (2004). Neuroanatomy: an atlas of structures, sections, and systems. Hagerstwon, MD: Lippincott Williams & Wilkins. ISBN 0-7817-4677-9. 

• Duffy, Joseph R (2005). Motor Speech Disorders: Substrates, Differential Diagnosis, And Management. 2nd edition.. Saint Louis: C.V. Mosby. ISBN 0-323-02452-1.