About this trial

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.

Eligibility criteria

This trial does not accept healthy volunteers

Qualifiers

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.

Age between 3;6 and 12;11 years.

Normal structure of the oral-peripheral mechanism as determined by a motor speech examination using established lab protocol.

Participants must pass a hearing screening conducted at 20 dB SPL at 500, 1000, 2000 and 4000 Hz.

Disqualifiers

Primary dysarthria diagnosis, even if CAS is a secondary diagnosis.

Abnormal structure of the oral peripheral mechanism.

Fluency disorder, even if the child meets criteria for CAS.

Conductive or sensorineural hearing loss, even if the child meets criteria for CAS.

Trial design

Design model

Parallel

Treatments tested in this trial

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.

Treatment groups

68 Participants

are divided into 2 treatment groups

Group A: Immediate TreatmentExperimental treatment 1 intervention

Group B: Delayed TreatmentExperimental treatment 1 intervention

Trial outcomes

Primary outcomes

1

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

1

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.

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;

2

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.

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;

3

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.

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;

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

About this trial

Eligibility criteria

Qualifiers

Disqualifiers

Trial design

Treatments tested in this trial

Treatment groups

Trial outcomes

Primary outcomes

Secondary outcomes

Other outcomes

Sponsors and contacts