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Trial registered on ANZCTR

Registration number
Ethics application status
Submitted, not yet approved
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
A randomised-controlled trial of low-intensity Early Start Denver Model therapy and parent coaching for young children with autism.
Scientific title
A randomised-controlled trial investigating the impact of low-intensity Early Start Denver Model therapy and parent coaching on child engagement, adaptive behaviour, social responsiveness, language and communication, compared to treatment-as-usual for young children with autism.
Secondary ID [1] 302636 0
HRC Emerging Research First Grant- 20/581
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
autism spectrum disorder 319534 0
Condition category
Condition code
Mental Health 317485 317485 0 0
Autistic spectrum disorders

Study type
Description of intervention(s) / exposure
Low intensity Early Start Denver Model (ESDM) group
The low-intensity ESDM package will be delivered by a team of two trained therapists/ researchers and one parent coach/researcher. Each child will receive two 1-hour direct therapy sessions per week for the full 26 weeks. All therapy sessions will take place in the Autism NZ Resource Centre in Petone. Their parents will receive a 1-hour home-based coaching session per week for the first 13 weeks, and 1-hour per fortnight for the remaining 13 weeks.
The therapists will be trained to implement the therapy according to the principles of the ESDM, as detailed in the official ESDM intervention manual. Each of the two weekly sessions will involve play with highly preferred objects and ‘sensory social routines’ with the therapist. Parents may be present during the sessions but will be instructed to minimise interaction with their child. The therapist will implement the therapy using the following ESDM fidelity items: (a) management of attention; (b) behavioural teaching; (c) modulation of affect and arousal; (d) management of unwanted behaviours; (e) dyadic engagement; (f) optimisation of child motivation; (g) positive affect; (h) sensitivity and responsivity; (i) use of multiple and varied communicative functions; (j) appropriateness of language; (k) use of flexible joint activity routines; and (l) smooth transitions.
The coach/researcher will implement each parent session according to the ESDM coaching manual. All information covered during the sessions will be based on the ESDM parent manual which will be given to each of the parents. One consistent parent will be required to participate in all of the coaching sessions. In the first 13 weeks, sessions will occur weekly and will last for one hour. The parent will select a strategy to learn every week, will practice this strategy with their child, and will reflect on this with the coach. In the following 13 weeks, when the parents have learned all the strategies, sessions will take place once a fortnight, and will focus on an area of the parents choosing or an area where parents have not yet reached fidelity. Sessions will involve the parent practicing all strategies with their child and reflecting on this with the coach.
Therapist and coach fidelity will be assessed by a trained researcher during 5% of sessions. Parents will also complete a log of the amount of hours per week that they use the ESDM strategies.
Intervention code [1] 318926 0
Comparator / control treatment
Treatment as usual control group
Families in the treatment as usual control group will receive 30-minute support phone calls from a researcher once a month. The researcher will listen to parents’ concerns, give general advice in response to parent questions, and provide referrals if requested by the parent. The support phone calls will not include any ESDM related content.
Control group

Primary outcome [1] 325519 0
Child engagement measured using an adapted version of Bakeman and Adamson's (1984) engagement measure.
Timepoint [1] 325519 0
At baseline, and six months after randomisation
Secondary outcome [1] 388263 0
Child language and communication- Eliciting Language Samples for Analysis – Toddler (ELSA-T)
Timepoint [1] 388263 0
At baseline, and six months after randomisation
Secondary outcome [2] 388264 0
Child developmental functioning- Mullen Scales of Early Learning (MSEL)
Timepoint [2] 388264 0
At baseline, and six months after randomisation
Secondary outcome [3] 388265 0
Child adaptive behaviour- Vineland Adaptive Behaviour Scales – 3rd edition (VABS-III)
Timepoint [3] 388265 0
At baseline, and six months after randomisation
Secondary outcome [4] 388266 0
Child social responsivity- Social Responsiveness Scale – Second Edition (SRS-2). This is a measure of autistic traits.
Timepoint [4] 388266 0
At baseline, and six months after randomisation
Secondary outcome [5] 388267 0
Parent use of ESDM techniques using the ESDM fidelity checklist
Timepoint [5] 388267 0
At baseline, and six months after randomisation
Secondary outcome [6] 388268 0
Parent use of NDBI techniques- Measure of NDBI Strategy Implementation- Caregiver Change (MONSI-CC )
Timepoint [6] 388268 0
At baseline, and six months after randomisation
Secondary outcome [7] 388269 0
Parent stress- Autism parent stress index (APSI)
Timepoint [7] 388269 0
At baseline, and six months after randomisation
Secondary outcome [8] 388270 0
Family quality of life questionnaire (FQOL)
Timepoint [8] 388270 0
At baseline, and six months after randomisation
Secondary outcome [9] 388326 0
Parent sense of competence questionnaire
Timepoint [9] 388326 0
At baseline, and six months after randomisation

Key inclusion criteria
Children and families will be eligible for this trial if: (a) the child is between the ages of 1 and 5 years at the start of the study; (b) the child has an official diagnosis of ASD, or the child is highly likely to be diagnosed with ASD because they meet the criteria for ASD diagnosis based on a clinician-administered ADOS-2 assessment; (c) the primary caregiver involved in the trial speaks sufficient English to understand the requirements of the study and to be able to participate fully in the coaching sessions; (d) the child does not have another serious medical, genetic, neurological or sensory condition (e.g., Down syndrome, fragile X); (e) the child is not receiving 15 or more hours per week of professionally implemented early intervention; and (f) the family does not intend to move out of the Wellington region during the 6 month pre-and post-assessment period.
Minimum age
1 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation will be done by a blinded investigator based solely on an ID number, and participant chronological age. Randomisation will occur centrally, on a computer.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Randomisation will be based on the Urn design method, which randomises participants while minimising group differences in chronological age.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?

The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
We will test changes in each of the primary and secondary child and parent outcomes with a 2 (intervention: low-intensity ESDM; treatment-as-usual) x 2 (time: baseline; follow-up) repeated measures ANOVA, comparing changes in the low-intensity ESDM group relative to the treatment-as-usual group.
The study is sufficiently powered to detect changes in the primary outcome measure of child engagement accounting for the population (children with ASD under 5 in the
Wellington region) and the intensity and duration of the intervention (2.5 – 3 hours per week for 6 months). The prior effect size for the impact of the intervention on engagement as 0.81. We aim to recruit 48 children, which will provide a two-tailed repeated measures ANOVA with 86% power to detect a 0.81 effect size and will allow for up to 6 families to drop out (retaining a level of power above 80%). The estimated effect sizes for tests involving secondary and tertiary outcomes are currently unknown, but we will take a conservative approach by adopting a more critical alpha to account for the multiple comparisons.

Recruitment status
Not yet recruiting
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment outside Australia
Country [1] 23077 0
New Zealand
State/province [1] 23077 0

Funding & Sponsors
Funding source category [1] 307067 0
Name [1] 307067 0
Health Research Council
Address [1] 307067 0
Level 3 - ProCARE Building, Grafton Mews, at 110 Stanley Street (GPS: 50 Grafton Road), Grafton, Auckland 1010
Country [1] 307067 0
New Zealand
Primary sponsor type
Dr Hannah Waddington
15C Waiteata Road
New Zealand
Secondary sponsor category [1] 307640 0
Name [1] 307640 0
Address [1] 307640 0
Country [1] 307640 0

Ethics approval
Ethics application status
Submitted, not yet approved
Ethics committee name [1] 307191 0
Health and Disability Ethics Committee
Ethics committee address [1] 307191 0
Ministry of Health
Health and Disability Ethics Committees
PO Box 5013
Wellington 6140
Ethics committee country [1] 307191 0
New Zealand
Date submitted for ethics approval [1] 307191 0
Approval date [1] 307191 0
Ethics approval number [1] 307191 0

Brief summary
Research suggests that 20 or more hours per week of intervention over several years
may lead to significant improvements in long-term outcomes for young children with autism spectrum disorder (ASD). However, many families are unable to access or afford intensive early intervention. In these cases, it is possible that intervention for a few hours per week may be of some benefit. The early start Denver model (ESDM) is a promising intervention approach which has not been carefully tested when implemented at a low-intensity. This proposed study will examine the effectiveness of 2 hours a week of ESDM therapy delivered by a training and 1 hour a week or fortnight of parent coaching for 6 months. Families will be assigned at random to receive this treatment or to receive monthly support calls (“treatment-as-usual). The children will be aged between one and five years. We will measure each child’s engagement. Child outcome measures will include engagement, life skills, cognitive abilities, autistic traits, and language and communication. We will also measure parents’ use of therapy strategies, their stress levels, their sense of competence, and their quality of life. Intervention approaches that only require a few hours of professional input per week have the potential to significantly improve outcomes for individuals on the autism spectrum and their whanau.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 106346 0
Dr Hannah Waddington
Address 106346 0
Victoria University of Wellington
15C Waiteata Road
Country 106346 0
New Zealand
Phone 106346 0
Fax 106346 0
Email 106346 0
Contact person for public queries
Name 106347 0
Dr Hannah Waddington
Address 106347 0
Victoria University of Wellington
15C Waiteata Road
Country 106347 0
New Zealand
Phone 106347 0
Fax 106347 0
Email 106347 0
Contact person for scientific queries
Name 106348 0
Dr Hannah Waddington
Address 106348 0
Victoria University of Wellington
15C Waiteata Road
Country 106348 0
New Zealand
Phone 106348 0
Fax 106348 0
Email 106348 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
What data in particular will be shared?
If participants consent, an excel file with their deidentified data for all outcome measures will be made available
When will data be available (start and end dates)?
Data will be available indefinitely following the study conclusion, which is anticipated to be in early 2023.
Available to whom?
Available for what types of analyses?
Analyses directly pertaining to the effects of low-intensity ESDM intervention for young children with autism.
How or where can data be obtained?
The data can be obtained by contacting the primary investigator (hannah.waddington@vuw.ac.nz)
What supporting documents are/will be available?
Study protocol
Informed consent form
Ethical approval
How or where can supporting documents be obtained?
Type [1] 9546 0
Study protocol
Citation [1] 9546 0
Link [1] 9546 0
Email [1] 9546 0
Other [1] 9546 0
Available from the principal investigator upon request
Attachment [1] 9546 0
Type [2] 9547 0
Informed consent form
Citation [2] 9547 0
Link [2] 9547 0
Email [2] 9547 0
Other [2] 9547 0
Available from the principal investigator upon request
Attachment [2] 9547 0
Type [3] 9548 0
Ethical approval
Citation [3] 9548 0
Link [3] 9548 0
Email [3] 9548 0
Other [3] 9548 0
Available from the principal investigator upon request
Attachment [3] 9548 0
Summary results
No Results