Types of Dysarthria: A Clinical Overview
A clinical overview of the types of dysarthria — the motor speech disorder classification by underlying pathology and characteristic speech features.
Dysarthria is a motor speech disorder rooted in neurological impairment: the muscles used for speech are weak or slow, and coordination breaks down with them. The types of dysarthria are classified by the location and type of the underlying lesion. Knowing them guides assessment and prognosis, and it sets up the treatment plan.
What dysarthria affects
Depending on the subsystem involved, the breakdown lands somewhere different: breathing (respiration), voicing (phonation), nasal tone (resonance), consonant precision (articulation), or melody (prosody). Listeners notice slurred or imprecise speech, voice quality or pitch that shifts, a rate or rhythm that's off, and intelligibility that's slipping. The specific pattern points to the type.
The major types
The widely used Mayo classification sorts dysarthria by the underlying motor system that's affected.
Flaccid dysarthria comes from lower motor neuron lesions. The voice goes breathy with nasal emission, and consonants come out imprecise (bulbar involvement is the classic setup). Spastic dysarthria means bilateral upper motor neuron lesions. Speech turns strained-strangled and effortful, with a slow rate and reduced prosody.
Ataxic dysarthria points at the cerebellum. You get imprecise articulation and irregular articulatory breakdowns, plus excess and equal stress across syllables. Hypokinetic dysarthria travels with parkinsonism: reduced loudness with monopitch and monoloudness, and a rate that goes rapid or rushed with reduced stress. Hyperkinetic dysarthria is the involuntary-movement type (dystonia, chorea), and speech features vary with the movement disorder.
Mixed dysarthria combines the types above, and it's common in conditions like multiple systems or amyotrophic lateral sclerosis, which can show combined upper and lower motor neuron signs. Unilateral upper motor neuron dysarthria comes from a single-sided lesion, and it's milder.
Assessment and goals
The assessment isn't my job. A speech-language pathologist works through the respiratory, laryngeal, and velopharyngeal subsystems (articulation too), using perceptual methods and instrumental measures, sometimes with imaging. Treatment gets tailored to the type and severity, aiming at intelligibility and compensatory strategies, and where appropriate prosthetic or augmentative communication.
Documentation
I get opinionated about documentation because I've seen motor speech notes that name a type and severity without ever connecting either to a measurable functional goal. Use the ICD-10 lookup for the correct code and the treatment plan goal builder to specify measurable speech outcomes.