Teasing Apart Childhood Apraxia of Speech

Published: December 5th, 2017

Category: UAD Student Blog

“I’m not sure” can be a typical feeling when speech-language
pathologists (SLPs) consider childhood apraxia of speech (CAS) as a
potential diagnosis for many reasons. There is not as much of a focus on
differential diagnosis for pediatric motor speech disorders in comparison to
other pediatric communication disorders. Additionally, CAS frequently
presents with motor speech and phonological deficits. Thus, CAS can be
commonly mistaken for dysarthria or phonological impairments (Strand,
2017).

CAS is a motor speech disorder in which the production of sounds,
syllables, and words are problematic for children. This difficulty is not due
to muscle weakness or paralysis of the speech musculature. Instead, CAS
involves a problem in coordinating the planning and/or programming of
muscle movements which allows the necessary articulators to move for
speech production (ASHA, 2007). The causes of CAS may include a known
neurologic event (i.e. stroke or brain injury) or genetic disorders (Hegland,
n.d.). However, the majority of cases are idiopathic (Murray, McCabe,
Heard, & Ballard, 2015).

When diagnosing CAS, the SLP must first determine whether a child’s
speech disorder is predominantly a motor planning problem, a
neuromuscular deficit, or a linguistically-based phonological impairment
(ASHA, 2007). To establish a diagnosis, the child must demonstrate
suggestive characteristics more consistent with CAS than with other speech
sound disorders (Murray et al., 2015). For example, children with CAS often
display vowel and consonant distortions, prosodic errors, equal stress
and/or segmentation, inconsistent production across trials, groping, trialand-error
behavior, voicing errors, and/or inaccurate articulatory
movements (ASHA, 2007; Strand, 2017). Although there is no standard
assessment battery for testing these characteristics of CAS, there are
suggested approaches to rule-out other diagnoses (Murray et al., 2015).
The reported patient history can conclude whether the child produced
limited-to-no babbling, more indicative of CAS. Delays in gross- and finemotor
movements are more frequently seen in children with CAS than in
phonological disorders. If problems with chewing, swallowing, and drooling
are noted, then the SLP should consider a possible diagnosis of dysarthria
rather than CAS. Subsequently, acquisition of a language sample can show
red flags of CAS if a child has a reduced phonetic inventory, unintelligible
speech, and distorted vowels (Strand, 2017).

Selecting specific assessment approaches should be dependent on a
child’s age, severity, and attentiveness. Firstly, the clinician can use an oral
motor examination to eliminate diagnosis of dysarthria and orofacial
structural abnormality (Murray et al., 2015). Checking for signs of
hypotonicity and/or weakness can suggest dysarthria if present, or CAS if
absent (ASHA, 2007). Children presenting with nonverbal oral apraxia
(NVOA) can increase the likelihood of also having CAS (Strand, 2017). A
variety of other assessments can rule-out diagnoses of expressive and
receptive language impairments (Murray et al., 2015). Secondly, the SLP
will conduct a dynamic motor speech examination to assess the child’s
production of sounds across syllable shapes and co-articulatory contexts.
The child must repeat words that are not typically used in his/her
spontaneous speech upon receiving gestural, tactile, and/or visual cues.
Therefore, the clinician will be more likely to observe CAS-type behaviors
(specifically, trial-and-error, groping, segmentation, and stress errors) and
better able to determine the severity and prognosis of the child (Strand,
2017).

Due to uncertainty in the discriminative characteristics and
assessment measures for diagnosing CAS, SLPs may be inclined to make a
diagnosis of “suspected CAS” until the child’s symptoms become more
prominent (Murray et al., 2015). On the contrary, a child’s prior diagnosis of
CAS may no longer be appropriate after further neural maturation and
speech-language treatment (Strand, 2017). Until additional research on the
differential diagnosis of pediatric motor speech disorders is conducted,
speech-language pathologists may experience some difficulty teasing apart
childhood apraxia of speech.

References:

American Speech-Language-Hearing Association [ASHA]. (2007). Childhood
apraxia of speech. Retrieved from
http://www.asha.org/public/speech/disorders/ChildhoodApraxia/

Hegland, K. (n.d.) Childhood apraxia of speech [PowerPoint slides].
Retrieved from https://ufl.instructure.com/courses/341120/modules

Murray, E., McCabe, P., Heard, R., & Ballard, K. J. (2015). Differential
diagnosis of children with suspected childhood apraxia of speech. J Speech Lang Hear Res,
58(1), 43-60. doi: 10.1044/2014_JSLHR-S-12-0358

Strand, E. (2017). Appraising apraxia. The ASHA Leader, 22(3), 50-58.
doi:10.1044/leader.FTR2.22032017.50