Diagnosing Childhood Apraxia of Speech/Motor Speech Disorders

Children that are not saying at least a few words by about fifteen to eighteen months should be referred for an assessment. This can be done through an Alberta Health Services Public Health Clinic in your area. A family doctor visit should be sought as well,  to have a general health screen done. Routine visits are usually opportunities for family physicians to screen for developmental delays and conditions, including those pertaining to speech and sound disorders. However, an experienced Speech-Language Pathologist would be the appropriate specialist to diagnose a Speech Sound disorder such as Childhood Apraxia of Speech. It must be known that a diagnosis of Childhood Apraxia of Speech cannot be made with certainty prior to three years or even four years of age.  Although it can be suspected with some measure of certainty, confirmation can really only happen after this age approximately, or even later in some cases. Up to this age, the provisional diagnosis will be “Suspected Childhood Apraxia of Speech”,  “Expressive Language Delay” (delay in the ability to produce and use language) and “Receptive Language Delay” (delay in the ability to understand language); these will range in severity from mild to severe in nature.  This diagnosis is made by an experienced Speech-Language Pathologist generally using expert judgment of perceptual features (as it appears) and other parameters (see below):

Features of CAS:(ASHA 2007b)

    • “Inconsistent errors on consonant and vowels in repeated productions of syllables and words.”
    • “Lengthened and disrupted coarticulatory transitions between sounds and syllables”
    • “Inappropriate prosody, especially in the realization of lexical or phrase stress.”

Other features include voicing errors, slow rate, and increase difficulty with longer, more complex words. Parents will often note that children have difficulty with longer sentences, and often will make an error with a word and this error will be different for the same word each time ie. inconsistent.

Historically, it has been about almost two decades now since researchers have looked into exactly what the typical features of Childhood Apraxia of Speech represent. Prior to this little was known about this disorder. Interestingly, the characteristic features of CAS have been agreed upon only in the last decade or so, as well as what exactly constitutes “planning and programming” of speech.

Essentially, children were found to have a speech disorder that looked very similar to the Adult Apraxia of Speech, known to be due to damage in parts of the brain that controlled the “planning and programming” of speech, that is, the speech area of the brain, a highly complex region with highly complex neurological procesess. However, no such “lesion” was seen in the cortex or other areas of children with the disorder, therefore, much research has gone into finding exactly what, then where, how, and why this disorder occurs.

Not withstanding all of this, it is still a matter of discussion about the actual “diagnostic criteria” that can predicate a diagnosis of CAS with certainty, to the exclusion of other conditions such as dysarthria (a motor speech disorder that is concerned with the “execution” of speech, eg weakness of muscles and structures required for articulation). Recently a group of researchers studied a series of objective measures to diagnose CAS (Murray, McCabe, Heard, Ballard 2015). While their study needs to be replicated, they were able to discern CAS with a 91% accuracy using Polysyllabic production accuracy (producing many sounds in sequence with accuracy) and Oral Motor Examination that included diadochokinesis (Repetitive alternation and sequencing of syllables).

The implications of this understanding are important.  While CAS can only truly be “suspected” early on, in Alberta there are services in place that target children in this young age group (ages 2-4) that would work on treating suspected Childhood Apraxia of Speech, giving benefit to those kids that truly have the condition and not harming, but in fact also benefiting, those that don’t.  For both sets of children that present in the same way (ie late talking), for the past five years SLPs working for Alberta Health Services have received training aimed at targeting this select group of children from Dr. Megan Hodge of the Communication Science Department at the University of Alberta.

Thus, an experienced SLP, versed in Childhood Apraxia of Speech, would be the ideal candidate to make such a diagnosis.

Read More Here (Apraxia-KIDS.org)

References:
ASHA.org/policy (2007b)

Murray E., McCabe P., Heard R., Ballard K.J. (2015)Differential Diagnosis of Children with Suspected Childhood Apraxia of Speech, Journal of Speech, Language and Hearing Research, Vol 58, 43-60.

Shriberg L.D., Aram D.M., & Kwiatkowski J. (1997) Developmental Apraxia of Speech: 1. Descriptive and Theoretical Perspectives, Journal of Speech, Language and Hearing Research, Vol 40, 273-285.

“Here’s How to Treat Childhood Apraxia of Speech”, Margaret Fish (2010) Plural Publishing.

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