Rapid Syllable Transition (ReST) and Related Interventions for Speech Sound Disorders in Children: A Master Protocol Investigating Treatment Approaches, Dose Frequency, and Delivery Modality

This research corresponds to the comparison between the group submitted to the intervention with the ReST method and the control group, maintaining the methodological rigor of the experimental design. The interventions will be conducted by different master's students, each responsible for one of the therapeutic approaches, while the doctoral student will be responsible for randomization, evaluations, and methodological supervision. The study design will follow the SPIRIT (Standard Protocol Items: Recommendations for Interventional Trials) recommendations, and the results will be reported in accordance with the CONSORT (Consolidated Standards of Reporting Trials) guidelines, in their most recent versions, including a checklist and participant flowchart. In addition, as this is a pilot randomized clinical trial, the study will also follow recommendations for pilot and feasibility studies, focusing not only on preliminary effects of the intervention, but also on assessing the feasibility of the procedures and generating parameters for a future confirmatory trial.

All participants and their guardians will receive information about the research and, after agreeing to participate, will sign the Informed Consent Form (ICF), the Assent Form, with the study having been previously submitted to and approved by the Research Ethics Committee. Considering recommendations for pilot studies and the rarity and clinical heterogeneity of the population, the inclusion of approximately 12 to 20 participants is expected. These will be Brazilian, monolingual individuals, aged between five and twelve years, all diagnosed with Childhood Apraxia of Speech (CAS). The sample size will be defined based on methodological justification specific to randomized pilot studies, and not on power calculations for confirmatory efficacy testing.

The inclusion criteria adopted will be: signed informed consent form by the guardians; patients who are native speakers of Brazilian Portuguese; absence of associated comorbidities, verified from a detailed clinical history and information provided by the parents; superior receptive language performance compared to expressive performance, confirmed by clinical observation and simple comprehension tasks; hearing thresholds within normal limits; preserved visual acuity; and age between five and eight years.

Children with significant cognitive impairments or severe comprehension difficulties that prevent participation in the proposed activities will be excluded.

In addition to the eligibility criteria, the diagnosis of AFI will be established by clinical consensus among experienced evaluators, based on multiple diagnostic sources and the presence of the clinical markers described for the disorder, including inconsistency in productions, prolonged and/or interrupted coarticulatory transitions, and prosodic alterations. Complementary instruments will be used to increase diagnostic accuracy and reduce clinical heterogeneity in the sample.