Motor-based Intervention for Childhood Apraxia of Speech: DTTC-Connect

N/ANot Yet RecruitingNCT07526246

New York University68 enrolled

Overview

Childhood apraxia of speech (CAS) is a complex motor speech disorder that significantly limits a child's ability to communicate in daily activities, with difficulties often persisting into adolescence and adulthood. There is solid evidence that motor-based interventions, such as Dynamic Temporal and Tactile Cueing (DTTC), improve word production in children with CAS. Building on this strong foundation, the next critical step is to extend this work to support functional communication in connected speech, where children with CAS often continue to struggle. There is a critical need for a systematic bridge within the context of treatment from word-level practice to connected speech, as robust word-level gains often fail to generalize to other speaking contexts. This work addresses this gap by transitioning children from word- to phrase-level practice using Dynamic Temporal and Tactile Cueing-Connect (DTTC-Connect), a novel, structured adaptation of DTTC that targets connected speech production. Our approach builds on established DTTC principles while incorporating progression to more complex utterances, offering a developmentally appropriate, research-informed pathway to functional communication. This study is a Phase II randomized controlled trial (RCT) designed to examine the efficacy of DTTC-Connect, a motor-based treatment that includes phrase-level practice to refine connected speech and support communicative participation for children with CAS. The overall objectives of this work are to test the efficacy of DTTC-Connect and document changes in speech motor control at the connected speech level in 68 children with CAS (3;6 - 12;11 years of age) who receive treatment twice a week for 8 weeks (16 sessions). The central hypothesis is that DTTC-Connect will lead to lasting improvements in phrase accuracy, speech intelligibility and speech motor control, ultimately enhancing a child's communicative participation.

The long-term goal of this research is to provide evidence-based treatment guidelines to enhance speech intelligibility and therefore, communicative participation, for children with childhood apraxia of speech (CAS). The overall objectives are to test the efficacy of Dynamic Temporal and Tactile Cueing-Connect (DTTC-Connect) and document changes in speech motor control at the connected speech level, when intervention is provided two times per week for eight weeks. The central hypothesis is that DTTC-Connect will lead to lasting improvements in phrase accuracy, speech intelligibility, and speech motor control, ultimately enhancing a child's communicative participation, as supported by our previous Dynamic Temporal and Tactile Cueing (DTTC) research and pilot data on DTTC-Connect. The following aims are examined: Aim 1: Quantify the effects of DTTC-Connect on connected speech accuracy and whether previous DTTC modifies response to DTTC-Connect. 68 children with CAS will receive 8 weeks of DTTC-Connect, with a subset of children returning from the prior DTTC randomized controlled trial (RCT). The working hypothesis is that untreated phrase accuracy (primary outcome) and speech intelligibility (secondary outcome) will increase pre-post DTTC-Connect with gains maintained at 8 weeks post-treatment in all children. It is hypothesized that prior DTTC RCT performance (returning participants) will predict untreated phrase accuracy pre-post DTTC-Connect. Linear mixed-effects models will be used to estimate the DTTC-Connect treatment effect and the moderation effect of prior DTTC exposure. Aim 2: Quantify the effects of DTTC-Connect on speech motor variability and whether previous DTTC modifies response to DTTC-Connect. Acoustic and kinematic (lip/jaw movement) data will be obtained pre- and post- DTTC-Connect from 68 children with CAS, including a subset of children returning from the prior DTTC RCT. The working hypothesis is that variability (secondary outcome) will be reduced in all children following DTTC-Connect, with changes maintained at 8 weeks post-treatment. Inclusion of returning children will allow the examination of extended treatment on speech motor control. It is hypothesized that the change in variability in the prior DTTC RCT will moderate the treatment effect with DTTC-Connect. Linear mixed-effects models will be used to estimate changes in variability over time as in Aim 1. Aim 3: Evaluate the effect of DTTC-Connect on communicative participation in children with CAS. Communicative participation (secondary outcome) will be assessed in all children pre- and post- DTTC-Connect. The working hypothesis is that children with CAS who receive DTTC-Connect will show meaningful gains in their attitudes about speaking and in caregiver-reported functional communication. Linear mixed-effects models will be used to estimate changes in communicative participation following DTTC-Connect. Upon completion of these aims, the expected outcome is to establish the efficacy of DTTC-Connect in a large cohort of children with CAS, while uncovering how previous response to word-level DTTC informs individualized treatment planning. In doing so, it will generate actionable insights to enhance clinical outcomes while also deepening theoretical understanding of speech motor learning in CAS.

Interventions

Dynamic Temporal and Tactile Cueing - Connect (DTTC-Connect)BEHAVIORAL

DTTC-Connect is a motor-based intervention designed to improve speech accuracy in children with CAS by targeting movement transitions within phrases. Treatment begins with selecting a target phrase identified through dynamic assessment as being within the child's optimal challenge point. Using this initial target, four additional phrases are constructed that systematically build in structural, phonetic, and grammatical complexity to support gradual progression in motor skill. Treatment begins with two-word phrases and follows the first three levels of the DTTC temporal hierarchy: Simultaneous Production → Direct Imitation → Delayed Imitation. The final step is Elicited Production where children produce the target at random intervals in the absence of a prior model. Aligned with standard DTTC, children initially receive maximal support during Simultaneous Production. As accuracy improves, support is faded and the child progresses to less supported levels of production.

Eligibility

Sex: ALLMin age: 3 YearsMax age: 12 Years

Medical Language ↔ Plain English

Inclusion Criteria: 1. Diagnosis of childhood apraxia of speech (CAS). The diagnosis will be made by two speech language pathologists (SLPs) who have extensive experience in the differential diagnosis of CAS. 2. Age between 3;6 and 12;11 years. 3. Normal structure of the oral-peripheral mechanism as determined by a motor speech examination using established lab protocol. 4. Participants must pass a hearing screening conducted at 20 dB SPL at 500, 1000, 2000 and 4000 Hz. 5. Not receiving speech treatment elsewhere over the course of this study, although language, augmentative and alternative communication (AAC) treatment, or similar non-speech treatment, would be permitted. 6. Language Testing: Receptive Language Index standard score greater than or equal to 70 on the Clinical Evaluation of Language Fundamentals - Preschool 3rd edition (CELF-P3) for children 3;6-5;11 years of age, or the Clinical Evaluation of Language Fundamentals - 5th edition (CELF-5) for children 6;0-12;11 years of age. 7. Nonverbal Cognition Testing: Standard score greater than or equal to 70 on the Developmental Assessment of Young Children-2nd edition (DAYC-2) for children 3;6- 5;11 years of age, or the Reynolds Intellectual Assessment Scales- 2nd edition, Remote (RIAS) for children 6;0-12;11 years old. 8. Evidence of multi-word spontaneous speech up to five syllables in length. 9. English as the primary language. Exclusion Criteria: 1. Primary dysarthria diagnosis, even if CAS is a secondary diagnosis. 2. Abnormal structure of the oral peripheral mechanism. 3. Fluency disorder, even if the child meets criteria for CAS. 4. Conductive or sensorineural hearing loss, even if the child meets criteria for CAS. 5. English is not the primary language.

Outcomes

Primary Outcomes

Phrase Accuracy

The primary outcome measure will be untreated phrase accuracy, quantified using the adapted Multilevel word Accuracy Composite Score (MACS) ratings for phrase-level stimuli. This composite score reflects the accuracy of four key areas: (I) segments (consonant \& vowel accuracy within-word and across-word boundaries); (II) phrase structure (maintenance of structures across the phrase); (III) movement transitions (smoothness and fluency across sounds, syllable, or words); and (IV) prosody (lexical \& phrasal stress). Each component receives a binary rating (0/1). Ratings will consider co-articulatory effects that naturally occur between words within connected speech.

Time frame: Immediate Group: Pre-Treatment Baseline; 1-week Post-Treatment; 8-week Post-Treatment; 16-weeks Post-Treatment; Delayed Group: Pre-Delay Baseline; Pre-Treatment Baseline (8-weeks post Pre-Delay Baseline); 1-week Post-Treatment; 8-weeks Post-Treatment;

Secondary Outcomes

Speech Intelligibility

Speech intelligibility will be assessed to evaluate how well a listener understands a child's connected speech. To elicit naturalistic yet structured speech, children will be audio-recorded while narrating a short story depicting a picture card series using the School-Aged Language Assessment Measures (SLAM). Ten representative utterances per child per time point will be selected, randomized, and presented to five naïve adult listeners for transcription. A mean intelligibility score will be derived from the percentage of words correctly transcribed. This method captures connected speech in a developmentally appropriate and controlled format while supporting consistency and ecological validity.

Variability

Acoustic variability will be quantified using the coefficient of variation from phrase duration. Kinematic variability will be measured using jaw and lip aperture Spatiotemporal Index (STI) values. To ensure reliable estimates, each session must yield a minimum of four analyzable productions per target, with a maximum of eight to balance representation across children with differing levels of speech accuracy.

Communicative Participation

The treating SLP will administer the Focus on the Outcomes of Communication Under Six (FOCUS-34) and the Intelligibility in Context Scale (ICS) to caregivers, who can complete these measures in person while their child receives treatment. If the caregiver is not present, the forms will be sent electronically, and the clinician will schedule a brief Zoom meeting to provide instructions. Completed forms can then be returned electronically. To examine children's feelings towards speech, the Communication Attitude Test (CAT) will be administered to children age six years and older and the KiddyCAT Communication Attitude Test for Preschool and Kindergarten Children Who Stutter (KiddyCAT) will be administered to children under 6 years of age.