Childhood Apraxia of Speech (CAS) is in terms of diagnosis and treatment a very challenging and complicated speech disorder in children. Children with CAS find it difficult or impossible to accurately produce speech sounds and/or words despite having a good understanding of language. Although there are several treatment approaches for CAS, there are very few published studies examining their efficiency and effectiveness. For example, at present, we do not know the amount of change in speech intelligibility (the degree by which their speech can be understood by a listener) or their ability to communicate effectively in real world situations (i.e., functional communication) following treatment. We also do not know if more intense treatment (although promoted by most clinicians) is actually better for this population. Thus, there is a strong need for well-designed research studies in this area to advance clinical practice.
In July 2011, the Childhood Apraxia of Speech Association of North America (CASANA) awarded a competitive clinical treatment research grant to Dr. Aravind Namasivayam of the Speech and Stuttering Institute in Toronto, Ontario, Canada. His team consisted of experts in the areas of CAS research (Dr. Ben Maassen, University of Groningen in the Netherlands), speech science (Dr. Pascal van Lieshout, University of Toronto in Canada) and speech disorders treatment (Ms. Margit Pukonen from the Speech and Stuttering Institute, Toronto, Canada). The CASANA funding was used in support of the research project titled “Exploring the Relationship Between Treatment Intensity and Treatment Outcomes for Children with Apraxia of Speech”.
Using the funds from the CASANA grant a specialized screening tool was developed to identify a subpopulation of two to five-year-old children, who demonstrated characteristics of CAS, from a larger database of 102 preschool age children with motor speech issues. All children received a specialized motor speech treatment program delivered by qualified speech-language pathologists in one of two possible treatment formats: high-intensity (2 times a week for 10 weeks) or low-intensity (1 time a week for 10 weeks). Each speech therapy session lasted for 45 minutes. The speech-language pathologists providing the treatment were randomly assigned to either of these treatment formats. A child’s ability to correctly produce speech sounds in words, speech intelligibility and functional communication were evaluated both before and after treatment. Speech intelligibility was assessed at the word-level (percentage of words correctly identified by a listener) and at the sentence-level (percentage of words correctly understood in imitated sentences by a listener).
Overall, the results of the study demonstrated that the outcomes of the high-intensity treatment were superior to those of the low-intensity treatment. Specifically, high-intensity treatment resulted in a significant change in a child’s speech production abilities, word-level intelligibility and functional communication when compared to low-intensity treatment. Furthermore, high-intensity treatment produced almost twice the amount of positive changes and had fewer children failing in treatment (i.e. not showing any real progress- especially for speech production) relative to the low-intensity treatment. However, neither high- nor low-intensity treatment improved sentence-level speech intelligibility in children with CAS.
This CASANA funded study represents the largest data set available to-date relating the amount of therapy induced change and treatment dose and its effects on speech intelligibility and functional communication outcomes in children with CAS. The results from the study could be used to set appropriate levels of clinician and parental expectations prior to treatment and could potentially guide clinical practice (e.g. amount and possibly type of treatment required for this population).
Importantly, even though positive changes were found for speech production and functional communication in CAS children with 20 sessions (2 times a week / 10 weeks) there was only minimal improvement in sentence-level speech intelligibility following treatment. Thus, the CAS children may benefit from more than 20 sessions of therapy and from a treatment program that systematically builds in practice of speech production targets in longer utterances (i.e. phrases, sentences, connected speech). At present additional analyses are being carried out to identify factors contributing to positive outcomes in children with CAS. For example, we ask which of the following factors affect a child’s treatment outcomes: child’s participation in the therapy process, amount of home practice and/or quality of parent-child interaction? With further analysis, we will be able to identify key factors that contribute to positive treatment outcomes in children with CAS and thus make a significant contribution to future clinical practice in this area.
[CASANA funded research dollars are raised through the Walk for Children with Apraxia of Speech]