Spastic dysarthria

From Neurosigns
Jump to: navigation, search
Dysarthria is defective articulation of sounds or words of neurologic origin.(1-3) In neurologic patients, the speech abnormalities most often encountered are dysarthria and aphasia. The essential difference is that aphasia is a disorder of language and dysarthria is a disorder of the motor production or articulation of speech. In dysarthria, language functions are normal and the patient speaks with proper syntax, but pronunciation is faulty because of a breakdown in performing the coordinated muscular movements necessary for speech production. Dysarthria may result from any central or peripheral disturbance of the innervation of the articulatory muscles, or diseases involving the neuromuscular junction or the muscles involved in speech production. A commonly used classification separates dysarthria into flaccid, spastic, ataxic, hypokinetic, hyperkinetic and mixed types. The two most common types are flaccid and spastic.

Spastic dysarthria often results from bilateral supranuclear lesions, rendering the muscles that govern articulation both weak and spastic. Phonation is typically strained-strangled, and articulation is slow. The tongue is protruded and moved from side to side with difficulty. Mouth opening may seem restricted and speech seems to come from the back of the mouth. The jaw jerk, gag reflex and facial reflexes often become exaggerated. ALS may cause dysarthria with both spastic and flaccid features.(4)

The video shows two patients with spastic dysarthria due to ALS, courtesy of Dr. Rick Barohn. Contrast this with the video of flaccid dysarthria (see Here the patients can pronounce the individual palatals and linguals better but articulation is slow and the voice sounds strained or strangled.


1. Campbell WW. Barohn RJ. DeJong's the neurologic examination, 8th ed. Philadelphia: Wolters Kluwer, 2020.

2. Campbell WW. Clinical signs in neurology: a compendium. Philadelphia: Wolters Kluwer Health, 2016.

3. Enderby, P. Disorders of communication: dysarthria. Handb Clin Neurol. 2013; 110:273-81.

4. Tomik B, Guiloff RJ. Dysarthria in amyotrophic lateral sclerosis: A review. Amyotroph Lateral Scler. 2010;11:4-15.