Childhood apraxia of speech (CAS) is a neurologically based, childhood speech sound disorder. CAS affects the precision and consistency of the movements which produce speech in the absence of neuromuscular deficits. It is an extreme difficulty or inability to plan or program the spatiotemporal parameters of speech movements in sequence, affecting prosody and speech sound production. Basically, the brain knows what it wants to say, but cannot properly plan and sequence the required speech sound movements. CAS may occur as part of a larger neurologic impairment, or it can occur in the absence of other impairment, for no known reason, considered an idiopathic neurogenic speech disorder.
According to the American Speech-Language and Hearing association (ASHA), "a well-trained speech and language pathologist with specific experience in pediatric speech sound disorders, including motor speech disorders, is the appropriate professional to assess and diagnose CAS." However, other professionals might be involved in diagnosing CAS, such as a pediatric neurologist, psychologist or pediatrician.
A comprehensive assessment is required, considering that CAS may co-occur or overlap other disorders. The assessment is accomplished using a variety of measures and activities, including both standardized measures, and formal and informal assessment tools, typically including: case history, oral mechanism examination, hearing screening, speech sound assessment (single-word testing and connected-speech sampling), spoken language assessment and literacy assessment.
There are few standardized assessment tools, and the professional has to be trained to appropriately apply and interpret them. The Kaufman Speech Praxis Test for children (Kaufman, 1995), normed for children from 2-6 years old, assists diagnosis and treatment. The Apraxia Profile (Hickman, 1997) is normed for children from 3- 13 years old, and is designed to describe apraxia characteristics in children with speech intelligibility deficits. The Dynamic Evaluation of Motor Speech Skill-DEMSS (Strand and Skinder, 1999) was developed to aid in the differential diagnosis of both younger children and those with more severe motor planning and programming difficulties, such as those in children with CAS.
CAS differs from case to case; specific interventions incorporate motor learning principles in an individualized treatment plan based on a child's needs and strengths. A variety of treatment techniques that incorporate the principles of motor programming or motor learning can be used in order to try to elicit "correct" speech movement gestures, providing frequent and intensive practice of speech targets, and focus on accurate speech movement, including external sensory input for speech production (e.g., auditory, visual, tactile, cognitive cues). In the Rapid Syllable Transition (ReST) program, strings of nonsense syllables are targeted, while in the Nuffield Dyspraxia Program (NDP3), intervention begins by targeting consonants and vowels in isolation. Alternatively, the Dynamic Temporal and Tactile cueing (DTTC) is based on the assumption that the primary impairment in children with CAS is difficulty in motor planning and programing of the gestures of the speech. It incorporates visual, auditory, tactile, and metacognitive cues to help the children to acquire and establish new motor speech plans. The Kaufman Apraxia of Speech Program works based on approximations to promote speech production. Speech and language are broken down into smaller units (consonants, vowels, syllables, and words) and built back up into the target behavior (age-appropriate motor-speech and expressive language skills) with the appropriate utilization of cues for strategic reinforcement (motor learning principles). Finally, Prompts for Restructuring Oral Muscular Phonetic Targets (PROMPT), is a tactually grounded, sensorimotor, cognitive-linguistic treatment, which emphasizes the importance of focusing on functional language within the context of social interaction.
Ultimately, early diagnosis and intervention is critical to support the child with CAS. Utilizing evidence-based approaches conducted by a qualified professional, in conjunction with parents and teacher support, helps the child with CAS meet their potential.
American Speech-Language and Hearing association (ASHA)
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