Dose Frequency RCT on DTTC in Children With CAS

Childhood apraxia of speech (CAS) is a pediatric motor-based speech sound disorder that requires a specialized approach to intervention (Maas et al., 2014). The extant literature on the treatment of CAS commonly recommends intensive treatment using a motor-based approach, with some of the best evidence supporting the use of Dynamic Temporal and Tactile Cueing (DTTC; Strand, 2020). To date, a rigorous and systematic comparison of high and low dose frequency has not been undertaken for DTTC, resulting in a lack of evidence to guide decisions about the optimal treatment schedule for this intervention. The current study aims to fill this gap in knowledge by comparing treatment outcomes when dose frequency is varied.

The goal of this clinical trial is to determine whether the number of treatment sessions per week has an effect on intervention outcomes in 60 children with CAS. The main question this research will address is whether whole word accuracy will differ between two groups of children undergoing DTTC treatment when one group of children receives treatment twice a week for 12 weeks and the other group receives treatment 4 times a week for 6 weeks. Community clinicians will administer all treatment sessions.

Sixty children with childhood apraxia of speech will be treated with DTTC treatment. A Phase III randomized controlled trial with parallel groups will be conducted to compare effects of low versus high dose frequency on DTTC treatment outcomes in children with CAS. Children with CAS between 2;5-7;11 years of age will be recruited to participate in this study. Treatment will be provided in the community setting by speech-language pathologists who have completed specialized training administering DTTC in a research reliable manner.

True randomization with concealed allocation will be used to assign children to either the low or high dose frequency group. Treatment will be administered in 1-hour sessions either 4 times per week over a 6-week period (high dose) or 2 times per week over a 12-week period (low dose) for a total of 24 hours per child. To measure treatment gains, probe data will be collected before treatment, during treatment, and 1 day, 1 week, 4 weeks, and 12 weeks post-treatment. Probe data will consist of customized treated words and a standard set of untreated words to assess generalization of treatment gains. The primary outcome variable will be whole word accuracy, a measure of segmental, phonotactic, and suprasegmental accuracy.

This will be the first randomized controlled trial (RCT) to evaluate dose frequency for DTTC treatment in children with CAS.

Eligibility Criteria:
Inclusion Criteria:

1. CAS diagnosis confirmed by research team as described below (e.g., Iuzzini-Seigel et al., 2022; Shriberg et al., 2017; Strand \& McCauley, 2019),
2. 2;6-7;11 years of age at treatment commencement;
3. English as the primary language;

Exclusion Criteria:

1. concomitant developmental disorders (including autism, global developmental delay, intellectual disability);
2. diagnosis of severe or primary dysarthria as described below;
3. palatal or structural orofacial anomalies as described below,
4. uncorrected vision impairment
5. hearing loss;
6. receiving speech treatment elsewhere over the course of this study, although language, augmentative and alternative communication treatment, or similar non-speech treatment, would be permitted
7. Receptive Language Index standard score less than 70 on the Receptive-Expressive Emergent Language Test, 4th edition (REEL-4; Brown et al., 2020) for children 2-3 years of age, the Clinical Evaluation of Language Fundamentals - Preschool 3rd edition (CELF-P3; Wiig et al., 2020) for children 4-5 years of age, or the Clinical Evaluation of Language Fundamentals - 5th edition (CELF-5; Wiig et al., 2013) for children 6-7 years of age,
8. Nonverbal Index standard score less than 70 on the Reynolds Intellectual Assessment Scales- 2nd edition, Remote (Reynolds \& Kamphaus, 2015), and
9. no evidence of communicative intent, attempts at verbal communication, focused attention to the clinician's face, or demonstrated ability to imitate during the DEMSS.