What is Apraxia of Speech?

Apraxia of speech (AOS) is an acquired oral motor speech disorder affecting an individual's ability to translate conscious speech plans into motor plans, which results in limited and difficult speech ability. By the definition of apraxia, AOS affects volitional (wilful or purposeful) movement patterns, however AOS usually also affects automatic speech.

Individuals with AOS have difficulty connecting speech messages from the brain to the mouth. AOS is a loss of prior speech ability resulting from a brain injury such as a stroke or progressive illness.

Developmental verbal dyspraxia (DVD), also known as childhood apraxia of speech (CAS) and developmental apraxia of speech (DAS);is an inability to utilize motor planning to perform movements necessary for speech during a child's language learning process. Although the causes differ between AOS and DVD, the main characteristics and treatments are similar.


Apraxia of speech can be caused by impairment to parts of the brain that control muscle movement and speech. However, identifying a particular region of the brain in which AOS always occurs has been controversial. Various patients with damage to left subcortical structures, regions of the insula, and Broca’s area have been diagnosed with AOS. Most commonly it is triggered by vascular lesions, but AOS can also arise due to tumors and trauma.