Developmental verbal dyspraxia

Developmental verbal dyspraxia (DVD), also known as childhood apraxia of speech (CAS) and developmental apraxia of speech (DAS), is a condition in which an individual has problems saying sounds, syllables and words. This is not because of muscle weakness or paralysis. The brain has problems planning to move the body parts (e.g., lips, jaw, tongue) needed for speech. The individual knows what they want to say, but their brain has difficulty coordinating the muscle movements necessary to say those words. The exact cause of this disorder is usually unknown. Many observations suggest a genetic cause of DVD, as many with the disorder have a family history of communication disorders. The gene FOXP2 has been implicated in many studies of the condition, and when this is the cause, the condition is inherited in an autosomal dominant manner, however roughly 75% of these cases are de novo. There is no cure for DVD, but with appropriate, intensive intervention, people with this motor speech disorder can improve significantly. "Childhood apraxia of speech (CAS) is a neurological childhood (pediatric) speech sound disorder in which the precision and consistency of movements underlying speech are impaired in the absence of neuromuscular deficits (e.g., abnormal reflexes, abnormal tone). CAS may occur as a result of known neurological impairment, in association with complex neurobehavioral disorders of known or unknown origin, or as an idiopathic neurogenic speech sound disorder. The core impairment in planning and/or programming spatiotemporal parameters of movement sequences results in errors in speech sound production and prosody." American Speech-Language-Hearing Association (ASHA) Ad Hoc Committee on Apraxia of Speech in Children (2007) There are three significant features that differentiate DVD/CAS from other childhood speech sound disorders. These features are: "Inconsistent errors on consonants and vowels in repeated productions of syllables and words Lengthened coarticulatory transitions between sounds and syllables Inappropriate prosody, especially in the realization of lexical or phrasal stress" Even though DVD/CAS is a developmental disorder, it will not simply disappear when children grow older.