What is CAS?
Childhood Apraxia of Speech (CAS) is a motor speech disorder. Children have trouble making speech sounds, not because of muscle weakness or paralysis, but because the brain has problems planning the movements needed for speech. When it is most severe, children struggle to make sounds. Children with a moderate or milder form struggle with syllables and words.
The frequency of CAS is not well understood. I have heard estimates of between 1-10 out of 1,000; in other words, between 0.01% and 0.1%. It appears that the frequency of CAS is growing, or at least an awareness of it is growing, perhaps leading to more diagnoses.
The cause or causes of CAS is not well understood either. It is a neurological disorder without any apparent brain injury. Children seem to be born with CAS. Hopefully, further research will be able to determine the cause or causes.
CAS goes by many names – Apraxia, Verbal Apraxia, Developmental Apraxia, Developmental Verbal Apraxia, Apraxia of Speech, Dyspraxia, and Dyspraxia of Speech. There may be even more that I am missing. Fundamentally, all of the names are trying to differentiate it from Acquired Apraxia of Speech. Victims of strokes who struggle to talk, exhibit many of the same characteristics of children with CAS. Hence the similarity in names. However, there are two major differences. Acquired Apraxia of Speech requires the ability to speak which was lost. Children with CAS were never able to speak in the first place. Furthermore, people with Acquired Apraxia of Speech have a lesion in their brain, usually from a stroke or a fall. As I stated before, the limited research on CAS has not shown an apparent brain injury.
There is some controversy about the name Childhood Apraxia of Speech. Adults may still suffer from CAS and often do not like the term childhood. However, I believe that what it is suggesting is that the disorder began in childhood rather than adulthood. In the end, no matter what you call CAS, it all boils down to a motor speech disorder of unknown origin beginning in childhood.