Parent-mediated Intervention for Toddlers With Early Social Communication Challenges or Emerging Autism: A Multi-site Randomized Controlled Trial of a Group-based Virtual Program That Empowers Parents as Change Agents
Phase: NA
Conditions: Autism Spectrum Disorder, Social Communication Disorder, Autism or Autistic Traits, Autism Spectrum Disorder With Impaired Functional Language, Autism-Related Speech Delay
Sponsor: Holland Bloorview Kids Rehabilitation Hospital

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STUDY PROTOCOL [VG-Social ABCs] 
 
Parent-mediated intervention for toddlers with early social communication challenges or 
emerging autism: A multi-site randomized controlled trial of a group-based virtual program that 
empowers parents as change agents  
 
1. The Need for a Trial 
Autism spectrum disorder (hereafter ASD or autism) is a neurodevelopmental disorder with 
increasing prevalence (>1.5%)1 and high personal, familial, and societal burdens. Core ASD 
symptoms include deficits in social communication and interaction (including impaired social-
emotional reciprocity and difficulty developing social relationships), and repetitive/restricted 
patterns of behaviour and/or interests2. Many autistic individuals require substantial and costly 
care across the lifespan from developmental, educational and behavioural services3, as well as 
health and mental health sectors4 due to high rates of comorbid conditions such as anxiety, 
depression, and ADHD5-10. Parental mental health is also often negatively affected, with elevated 
levels of stress11, anxiety, depression, and burnout12. Access to early intervention can reduce 
long-term costs3, but is severely hampered across Canada by long wait times for diagnosis and 
entry to intervention services. Developing innovative solutions that increase access to earlier 
intervention and parental supports can mitigate the need for intensive developmental services and 
later supports, thus reducing down-stream individual, family, and system costs and improving 
long-term outcomes3,13.  
 
1.1 What is the problem to be addressed? 
 
Across Canada, toddlers with autism have almost no access to diagnosis-specific intervention due 
to years-long delays in accessing a diagnosis (i.e., up to two years)14,15 followed by at least an 
additional two years’ wait to access intervention services in many areas16. These delays have only 
been exacerbated by Covid-19-related isolation measures17. This means that the vast majority of 
high-risk toddlers miss out on early intervention during the narrow developmental window when 
their brains are most amenable to treatment. Concurrently, parents of children with autism, 
already at risk for significant mental health challenges11,12, experience increasing distress as they 
watch their children fail to achieve key developmental milestones and as they struggle to manage 
their toddlers’ emotional dysregulation associated with core autism symptoms and functional 
communication deficits. Long-term cascading effects result in children requiring more intensive 
and/or longer duration of later interventions, with increased costs to the system, coupled with 
parental hopelessness leading to burnout12. This dire situation can be mitigated by capitalizing on 
parent-mediated intervention that takes place in the family’s home and can be initiated at the first 
signs of risk for autism (i.e., as early as one year of age18). Empowering parents to become 
engaged as the active agents of change for their toddlers, as early as possible, can significantly 
enhance child outcomes and mitigate parental stress. 
 
Informed by two decades of longitudinal research with high-risk infants and toddlers19,20, our 
team developed and demonstrated the efficacy of a 12-week parent-mediated intervention for 
toddlers with confirmed or suspected autism (the Social ABCs)21,22. Co-created with parents and 
Coaches, the approach operates within a developmental framework, in the child’s natural 
environment, using strategies of applied behaviour analysis (thus a Naturalistic Developmental 
Behavioural Intervention; NDBI)23. By directly targeting the parent-child dyad, the intervention 

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yields positive outcomes for both toddlers and their parents that are foundational for positive 
developmental and mental health outcomes: increased positive affect-sharing and social 
communication in toddlers, and parental empowerment via bolstering their skills and confidence 
in supporting their children’s development (study findings are further detailed below). 
 
1.2 What is the principal research question to be addressed? 
 
In toddlers (aged 18-42 months) with confirmed or suspected autism, is virtual, Group-based 
intervention using the Social ABCs model, more effective than treatment as usual at increasing 
toddlers’ vocal responsiveness to their primary caregivers (i.e., parents)? 
 
1.3 Why is a trial needed now? 
 
Given the rapidly rising prevalence of autism, and significant barriers to accessing traditional 
interventions, there is an urgent need to develop and evaluate innovative delivery models that can 
be accessed when the first signs of autism emerge. Promising ways to address this urgent need 
include (1) involving primary caregivers (hereafter, ‘parents’) as mediators of the intervention, (2) 
increasing access via virtual platforms, and (3) providing group-based interventions.  
Recent reviews highlight the promise of parent-mediated interventions for young children with 
emerging autism, with evidence of gains in key areas of social, communication, and play 
development23,24. A small number of studies have also examined the efficacy of virtual parent 
training methods, motivated by efforts to increase access. A recent systematic review25 identified 
7 studies of virtual parent-training models, three of which focused on toddlers with autism. 
Limitations due to weak study design (only 2 studies were RCTs), small samples, lack of 
measurement of child outcomes, no blinding, and variable or unspecified treatment durations 
were identified. Only three studies used live, two-way videoconferencing, and only one of these 
involved toddlers26, but with a very small sample (n = 8). Despite these limitations, the review 
concludes that virtual training in parent-mediated intervention “could benefit both parents and 
children with ASD given the barriers they face in accessing traditional services” 25.   
A very recent review of virtual delivery (“video-therapy”) in general mental health intervention 
identifies the rapid increase in virtual intervention in response to Covid-19 isolation measures, 
highlighting the need for more evidence in support of such approaches27. With respect to group-
based video-therapy, the authors conclude that the evidence is even more scant, but extant 
literature does point to feasibility and “roughly comparable outcomes between in-person and tele-
group treatments27”. Group-based mental health approaches stand apart as being more cost-
efficient than individual therapy, and having potential to add unique therapeutic value28.  
 
Supported by the above evidence, we argue that an innovative and promising approach to 
increasing access to autism intervention in the very early years involves virtual delivery of a 
group-based approach to parent training. We are currently pilot testing such an intervention 
(described below), which is now ready for formal evaluation through a well-powered RCT.   
The Social ABCs intervention is uniquely well-poised for virtual delivery as evidenced by the 
initial success of our pilot evaluation (see below). Our model differs substantially from many 
approaches in its use of a specific set of manualized, active, in-the-moment, supportive parent-
coaching strategies that are easily translated to virtual delivery. For example, although used by 
almost all other parent-mediated approaches, we intentionally avoid a training technique called 

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‘modelling’ (i.e., working directly with the child to demonstrate strategies to the parent). Our 
intentional avoidance of modelling was motivated by a commitment to supporting parents to 
develop their own ‘style’, to promote positive parent-child interaction, and foster parental 
empowerment. This unique coaching stance, shown in our previous work to successfully promote 
parent skill acquisition and self-efficacy, makes the Social ABCs ideally suited to virtual delivery. 
The virtually delivered Group-based model, proposed for the current evaluation, is an adaptation 
of our original (12-week, individual, in-person) Social ABCs program. Our original model has 
been shown to be feasible and acceptable21, and a cross-site RCT22 demonstrated improvements in 
toddlers’ communication skills (i.e., significant gains in toddler vocal responsiveness and 
initiations; p’s < .001), parent positive emotion-sharing (p = .017; which predicted gains in child 
smiling), and a trend toward increased toddler social orienting (p = .054). Parents learned the 
techniques (i.e., fidelity >80%) and reported increased self-efficacy (p = .009)22; qualitative 
analyses of parent interviews revealed themes of empowerment and hopefulness29. We have also 
now successfully completed a large community implementation (n = 183)30-33, with effectiveness 
commensurate with efficacy shown in our initial RCT, across a wide range of parent factors 
(gender, English language learner status, educational attainment [ranging from grade 9 to 
graduate school completion]) and child variables (age, sex, language skills)32. We have made two 
key adaptations to the original model, with promising pilot findings (described in section 2.19).  
 
1.4 How will the results of this trial be used? 
 
This project addresses the acute developmental and mental health needs of individuals with 
disabilities, as well as their families, identified by KBHN and CIHR as priority populations. 
Outcomes will establish the evidence needed to fill an urgent gap in the system –increasing access 
to treatment for toddlers at the first signs of risk by empowering parents as the agents of change.  
 
In most Canadian jurisdictions, ASD service funding is very difficult to access under age two. 
Moreover, there is a complete lack of funding/services specific to the needs of toddlers with 
emerging signs of ASD who do not yet have a confirmed diagnosis. There is a traditional care 
pathway of generic followed by diagnosis-specific intervention that misses opportunities for more 
targeted approaches. Similarly, there is a chronic gap, in publicly funded community service 
models, between early detection and early intervention that does not reflect the state of current 
evidence (i.e., we can identify the early signs, but despite the existence of evidence-based 
interventions, there is little that parents can access when initial signs are identified). 
 
Results from this trial will contribute evidence that can be used to make the case for very early 
intervention as soon as autism-related concerns arise. Exploratory examination of factors related 
to feasibility and acceptability will inform future implementation work. Our research is embedded 
in community-based clinical intervention programs, with training partnerships across Canada 
(e.g., McMaster Children’s Hospital, Children’s Hospital of Eastern Ontario, and Glenrose Rehab 
Speech-Language services in Alberta) and ongoing collaborations in India (Sethu Centre for 
Child Development in Goa, as part of the Indo-Canadian Autism Network Symposium; see 
www.socialabcs.ca for details) and in Israel (in collaboration with The Hebrew University; see 
www.autismchildfamily.com for details). 
 

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Knowledge mobilization will involve engaging Holland Bloorview’s Evidence-to-Care team to 
co-develop lay summaries, and support uptake of research findings into practice. We will share 
study findings through scientific conferences and community meetings (e.g., Infant Mental Health 
Promotion, Canadian Paediatric Society (CPS), infant development, psychiatry and psychology 
training programs, and relevant provincial ministries). Team members’ leadership roles within 
professional associations and relevant policy-advisory groups (see CVs and Most Significant 
Contributions) will provide platforms through which to share findings and influence provincial 
policy and national practice. Our team has an established record of translating empirical findings 
into clinical practice (e.g., CPS practice statements, 2019; www.cps.ca/en/documents/tag/autism).  
 
1.5 Are there any risks to the safety of participants involved in the trial?  
 
We have delivered the Social ABCs intervention to over 300 families (across our initial pilot 
study, two RCTs, community implementation work, and our current pilot evaluation of the in-
person and virtual Group models) without any significant adverse events. Use of a virtual 
platform presents potential risks associated with breach of privacy (mitigated by the use of Zoom 
for Healthcare which is compliant with Canadian healthcare privacy and security regulations). 
Risk of miscommunication or of missing out on important indicators of mental distress may also 
be elevated. However, “seeing” more of the family/home circumstances may also provide 
increased information that would guide the need to follow up regarding mental health or social 
supports. As with in-person intervention trials, our team is equipped to support parents who 
express distress (often associated with this early phase of identifying their young child’s 
developmental challenges) via providing supportive advice, offering families access to local team 
leads (all with clinical credentials), and/or helping families navigate community mental health 
resources, as appropriate. Notably, our parent-mediated intervention (which might be viewed as 
placing extra demands on parents) did not lead to increased stress in our original RCT22.  
 
1.6 How will potential participants learn about the study? 
 
The study team will prepare recruitment letters (to be approved by REB) and will share these 
electronically with community leaders and clinicians both within and outside of the main study 
centres (Holland Bloorview, Glenrose Rehab, and the IWK). These letters will be sent at the 
beginning of our recruitment period, and the clinicians receiving the information letters will share 
them with potential participants at the time of clinical care. This is the same process that we have 
used for recruitment in our previous and ongoing studies and it has worked very well. Families 
are given the recruitment letters and they may call our team if interested in participating or 
learning more.  
2. The Current Trial 
 
2.1 What is the trial design?  
 
This is a multi-site, single-blind, randomized group treatment trial. Participants are subjected to 
three design components (further detailed below): (1) parallel group design with a treatment and 
an active control arm, (2) own-control (within subject) design for the control arm after these 

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participants receive treatment (control-treatment), and (3) growth curve analysis of treatment 
group at Time 0 (baseline), Time 1 (after treatment), and Time 2 (follow-up).  
 
2.2 What are the planned trial interventions?  
 
Once consent is obtained, baseline (Time 0) video and questionnaire data are collected and then 
allocation to treatment arm is revealed. In cases of allocation to Arm A, an assigned Coach meets 
with each family to discuss family scheduling preferences for coaching sessions, technology 
issues, and child skills/interests, and then intervention begins.  
 
Arm A. The intervention is the Group Social ABCs, adapted for virtual delivery (VG-Social 
ABCs). The intervention will be provided to small groups of parents (4-8 per group) who meet 
virtually for a series of six didactic learning sessions led by two Coaches, supported by our 
Parent Manual available in English and French; although all coaching will be in English),  
PowerPoint slides and involves facilitation discussion, reflection, and idea generation. Each 
family is assigned a Coach, and one parent per family will receive nine individualized, 1:1 
coaching sessions over a 6-week period via the virtual platform (see Appendix A for study 
sessions). Parents will participate in an introductory virtual session at which the Coach introduces 
the aims and structure of the program, discusses family scheduling preferences, technology 
issues, and child skills/interests, obtains research consent, and collects a ten-minute pre-coaching 
video recording of the child interacting with the parent (time 1); baseline questionnaires are 
completed at this time as well. Following the 6-week intervention, a second parent-child 
interaction video is taken (time 2) and post-intervention questionnaires are completed by the 
coached parent; a follow-up video is collected at time 3 (see below). For all video recordings, 
parents are instructed to: “play with your child as you typically play, and try to capture both you 
and your child on the video”. Videos will be collected over the virtual platform, saved to virtual 
drives within institutional firewalls, and shared securely for video coding, based on formal data 
sharing agreements. Parent Coaches will be existing Social ABCs Coaches from all three sites 
(with backgrounds in Psychology, Early Childhood Education, Speech-Language Pathology, or 
Applied Behaviour Analysis), all with substantial in-person parent coaching experience, recent 
virtual coaching experience, and cross-site reliability. Our team will meet regularly to ensure 
consistency of virtual coaching practices and for supervision, using case-based video review per 
our longstanding model of cross-site reliability and clinical supervision. During this phase, 
families will be asked to limit other interventions to 1 hour/week each, as per our current 
protocols. See Appendix B for contents and selections from Parent Manual and Coaching Manual. 
 
Arm B. The active control condition controls for the co-intervention of group-based general 
support (i.e., regular contact with a supportive facilitator, interaction with other families), but 
without the ‘active ingredient’ of parent coaching that is fundamental to the Social ABCs. This 
condition involves three, bi-weekly (virtual) group-based sessions (i.e., groups of 4-8 parents, 
over 6 weeks) with a psychoeducational curriculum delivered by study personnel and Psychology 
graduate students not directly involved in the Social ABCs sessions. Families may access any 
available services in their communities (i.e., treatment as usual), which are recorded on our ST 
Form24. Given the current (extremely limited) availability of community early interventions and 
the brevity of the study, we anticipate that families will have limited access to other intervention 
while in the control condition (e.g., families in our previous study accessed < 1 hour/week of 

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“other” interventions over 6 months24). Families will be offered the VG-Social ABCs program 
after completing Arm B. Despite some concern that a waitlist control design can exaggerate 
treatment effects37, we feel ethically driven to offer the program after participation in the control 
condition. Moreover, the inclusion of a waitlist component to the active control condition may 
lessen the treatment effect, strengthening our confidence in positive findings. Data collection and 
time-points are the same as for the intervention arm (Arm A).  
 
2.3 Proposed practical arrangements for allocating participants to trial groups.  
 
Third-party randomization will be conducted. Random block sizes of 10 participants will be used 
for treatment assignment. There will be 12 blocks of each size for a total of (10*12) 120 
participants, 60 participants per treatment arm (5*12=60), drawn to account for 20% loss to 
follow-up eight blocks (8*10=80) for n = 100 in each arm. A trickle process will allow for 
sequential enrollment36. 
2.4 Proposed methods for protecting against sources of bias.  
 
This is a single-blind study. Blinding of families and Coaches to group assignment is not possible 
given the nature of the intervention, which is delivered by Coaches and mediated through parents. 
However, video coders, who will collect data for the primary outcome (and many secondary 
outcomes), will be blind to both treatment allocation and time (pre-intervention, post-intervention, 
follow-up). 
 
2.5 What are the planned inclusion/exclusion criteria? 
 
Inclusion Criteria. Eligibility will be based on elevated scores on the Autism Parent Screen for 
Infants (APSI37) supported by expert clinician impression of red flags for autism spectrum 
disorder (ASD), or a confirmed diagnosis of ASD made by a qualified professional (parents will 
be asked to provide the clinical report). Toddlers will be between ages 12 and 42 months at 
enrollment, having been born between 36 and 42 weeks’ gestation, with birthweight >2,500g and 
no neurological, genetic, or severe sensory or motor conditions. Participating families must be 
residing in Ontario, Nova Scotia, or Alberta at the time of participation. 
 
Requirements for participation include ability to comprehend verbal English instructions. Our 
Parent Training Manual is written at a grade four language level, but concepts are shared verbally 
and through images, so literacy is not a requirement. Participation is also dependent on access to 
high-speed internet and willingness to be video-recorded, for cross-site consistency checks and 
data acquisition. Parents will be asked to limit other social communication intervention programs 
(e.g., through Speech-Language Pathology, Occupational Therapy, Applied Behaviour Analysis, 
or related services) to 1 hour per week. Parents will also complete weekly services log to 
document involvement in such programs. Finally, parents will be encouraged to try not to miss 
more than 2 sessions in a row. Missed sessions will be rescheduled if possible. However, all 
families will be invited to provide end-of-study data even if multiple sessions are missed (number 
of sessions attended will be used as a covariate in analyses). Families may withdraw at any time. 
 
There are no exclusion criteria other than failure to meet inclusion criteria.  

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2.6 Proposed duration of treatment period.  
 
Treatment duration is 6 weeks. Time span between data collection time points will range from 7 
to 9 weeks to allow for re-scheduling if necessary.   
 
2.7 Proposed frequency and duration of follow up.  
 
Data will be collected for both groups at: baseline (Time 0), 6 weeks later (Time 1; within 6-8 
weeks), and following the next 6 weeks (Time 2; within next 6-8 weeks). Time 2 for the treatment 
group provides follow-up data to examine maintenance of gains in our primary outcome (toddler 
vocal responsiveness) and parent fidelity. 
 
2.8 What are the proposed primary and secondary outcome measures? 
 
Primary Outcome: Toddler vocal responsiveness (blind video-coded). 
Secondary Outcomes: 1. Toddler outcomes: (a) vocal initiations, (b) social orienting, (c) words 
understood and used, (d) autism symptoms; 2. Parent outcomes: (a) implementation fidelity, (b) 
self-efficacy, (c) stress.  
 
Exploratory Analyses: 1. Predictors: Child factors (e.g., sex assigned at birth, age, baseline 
language level, ASD symptoms) and parent/family factors that may influence outcomes (e.g., 
parent gender, parenting role, educational attainment, employment, stress, ethnicity, English 
spoken at home, family structure)40; 2. Implementation metrics: Feasibility and acceptability (see 
below). 
 
2.9 How will the outcome measures be measured at follow up? 
 
Primary Outcome: Toddler vocal responsiveness. Consistent with our previous work21,22, video 
coding will be used to measure toddlers’ vocal responsiveness (proportion of appropriate child 
vocal responses following a caregiver prompt, from 10-minute video). All video coding will be 
conducted by blinded research staff with established reliability, per established protocols. The 
primary outcome is change in toddler vocal responsiveness from time 0 to time 1. 
 
*For all parent-child interaction videos, parents are instructed to: “play with your child as you 
typically play” and reminded that: “we want to see both of you on the screen as much as 
possible”. Two 10-minute video clips will be collected and coded per time point (using average 
per time-point for analyses); no coaching occurs during data videos. Videos will be collected 
by research staff over the virtual platform, saved to virtual drives within institutional firewalls, 
and shared securely for coding, based on formal data-sharing agreements. Blinded research staff 
with established inter-rater reliability will code all videos, per established protocols. 
 
Secondary Outcomes (all measures used in our previous and/or ongoing work):  
1. Toddlers. (a) Vocal initiations and (b) social orienting (both blind-coded from video); (c) 
parent-rated word inventory (MacArthur-Bates Communicative Development Inventory [CDI]38); 
(d) autism symptoms (APSI37). 2. Parents. (a) Correct use of Social ABCs strategies (% 

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implementation fidelity from blind-coded video), (b) self-efficacy (Parent Self-Efficacy Scale22 
developed for our previous work), (c) parenting stress (Parenting Stress Index-4-Short Form39).  
 
Exploratory Analyses:  
1. Predictor variables: Continuous (parenting stress, child age, baseline word inventory, ASD 
symptoms) and categorical (toddler sex, parent gender, parenting role, educational attainment, 
employment, ethnicity, English spoken at home, family structure), variables (collected from the 
Family Profile Form24) will be assessed for their effect on the outcomes; 2. Implementation 
metrics. We will measure acceptability using our post-treatment Parent Satisfaction Scale22, and a 
Coaches’ Satisfaction Scale (under development) to capture Coaches’ perceptions of the adapted 
model relative to the standard approach. Program quality metrics will include evaluation of 
Coaches’ fidelity (based on pre-established video-coding methods). We will examine participant 
flow metrics such as referral sources, ages of children, and number referred, eligible, enrolled, and 
completed, as well as number of sessions attended/missed/rescheduled.  
2. Sub-group and predictor analyses will explore child factors (e.g., age, sex, baseline language 
level) and family factors that are facilitators or barriers to treatment uptake and successful 
outcomes (e.g., parents’ educational attainment, current employment, family structure, parent 
gender)40, using data collected from a Family Profile Form used in our previous work22.  
3. Follow-up (treatment group only). A 10-minute parent-child interaction video will be collected 
and coded for toddler responsiveness and parent implementation fidelity using the same 
procedures as for time 1 and time 2.  
 
2.10 Proposed sample size and justification for assumptions underlying power calculations. 
 
We aim to enroll 120 families into the RCT, across the three participating sites. 
 
This project has two phases, differing only by number of participants and funding source.  
Specifically, phase 1 (funded by Kids Brain Health Network) involves enrollment of 30 families 
across the 3 participating sites. For phase 2, funds are being sought through CIHR (to be 
adjudicated in March 2021). If funded, we will submit an amendment to increase recruitment up 
to 100. The proposed sample (n = 100; ~50 per treatment arm) will yield 80% power to detected a 
medium effect (at alpha = .05)41. The assumption of a medium effect comes from our previous 
RCT which yielded R2 = .43 for the same primary outcome22. We will over-sample by 20% (i.e., 
recruit to n = 120) to allow for attrition (see 2.14). Given that this is an individually randomized 
group treatment trial (with 1 group-based and 1 individually administered arm) analyses will 
account for the intra-class correlations associated with group participation, as recommended34. If 
Phase 2 is not funded, we will use data from Phase 1 as pilot data for further funding applications.  
 
2.11 If applicable, will health service research issues be addressed?  
 
This is not primarily a health services proposal. However, exploratory investigation of issues 
related to feasibility (# of families invited, enrolled, completed) and acceptability (via parents’ 
satisfaction ratings) will inform future implementation work. Our ongoing KBHN-funded work 
focuses on training and community implementation, including health economics analyses, with 
ongoing consultative support from M Barwick (Senior Scientist in the Department of Psychiatry 
and Child Health Evaluative Sciences program at SickKids’ Research Institute in Toronto). 

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2.12 Planned recruitment rate, organization, time period.  
 
Families will be recruited from our three collaborating sites through clinical and research units 
and community partners. Recruitment will begin in Year 1 (2nd quarter; Q2) and conclude in Year 
3 (end of Q1), allowing sufficient time to code and analyze data for manuscript preparation in 
Year 3 (see Timeline in Appendix C). Per regional populations and enrollment rates in related 
work, expected recruitment rates are as follows: (Toronto: 50, Edmonton: 40, Halifax: 30). 
Recruitment is anticipated to be successful based on the current pilot phase (i.e., the number of 
interested families currently far exceeds our capacity to enroll them). All three sites have been 
recruiting high-risk infant siblings of children with autism for longitudinal studies for almost two 
decades, and are thus well known in our respective communities and have established recruitment 
pipelines through community partners.  
 
2.13 Are there likely to be any problems with compliance?  
 
We will measure both program compliance and treatment fidelity. Compliance rates will be 
measured by the number of training sessions attended. As in our previous and ongoing work, 
families will be permitted to miss and reschedule up to 3 individual coaching sessions. Families 
who miss up to two group didactic sessions will receive session content in a subsequent 1:1 
session with their coach. Since the program does not require families to use the strategies for any 
pre-specified amount of time per day, attendance is our best measure of compliance. However, 
our established measure of parent implementation fidelity provides an index of parents’ skill 
acquisition which serves as a proxy for their amount of practice. In our RCT, 87% of families in 
the treatment condition achieved our target fidelity rate by the end of the program19. 
 
2.14 What is the likely rate of loss to follow up?  
 
Retention rates of 85-90% are expected, based on our previous RCT22 and current pilot work. In 
the initial RCT, >90% of families remained at 6-month follow-up (Treatment: 90.3%; Control: 
93.8%). Retention in our pilot evaluation of the virtual Group-based model is currently at 86% 
(19 of 22 have completed the program). Retention rates are anticipated to be similar to previous 
rates and may be further supported by the virtual nature of the project (i.e., families do not have to 
travel to participate). However, due to uncertainties associated with family availability (e.g., in 
response to Covid-19-related changes in work stoppages or isolation practices), we will over-
sample to 120 to ensure we reach our target of 100 completers.  
 
2.15 How many centres will be involved?  
 
Three collaborating sites across Canada: Holland Bloorview (Toronto, ON), IWK Health 
(Halifax, NS), and Glenrose Rehab (Edmonton, AB). 
 
2.16 What is the proposed type of analyses? 
 
The primary analysis will yield a comparison of rates of toddler vocal responsiveness between the 
two conditions, controlling for the variables described above. The statistical model for the  

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Primary Outcome will be either a Poisson or negative binomial regression (if there is 
overdispersion of the counts), using the number of prompts and/or time as offsets and applying 
the appropriate correlation structure for observations by participant, and controlling for intraclass 
correlation due to clustering. Growth curve analysis will be used to calculate the trajectory of 
change in responsive vocalizations over time for each person based on whatever data are available 
(if at least 2 measurements), and then estimates (imputes) the missing data if the person followed 
the same trajectory. Otherwise, a worst-case (no vocal response) scenario can be used.  
 
Secondary Outcomes: We will analyze as per the primary outcome for count variables (e.g., 
video-coded toddler initiations). We will use repeated measures ANOVA or Generalized 
Estimating Equations for scores (e.g., word inventory, ASD symptoms, parent efficacy, stress). 
 
Exploratory Analyses: (1) Predictors of primary and secondary outcomes will first be assessed 
univariately for their effect on the outcomes, and significant factors will be subjected to 
multivariate analysis using the appropriate regression model. We will examine the influence of 
sex (toddlers), parent gender, and parenting roles by entering these factors as covariates. Given 
that sample size calculations are not done for all these factors, these analyses are exploratory. (2) 
Implementation metrics (feasibility, acceptability) will be examined descriptively.  
 
2.17 Proposed frequency of analyses. Analyses will be conducted at two time points: (1) 
following the end of Phase 1 (n = 30), and (2) at the end of the larger trial (n = 100).  
 
2.18 Planned subgroup analyses.  
 
Subgroup analyses, run separately for treatment and control groups, will explore effects of: (1) 
sex: Do outcomes differ for boy vs. girl toddlers?; (2) gender: Are there differences in parent 
fidelity and self-efficacy based on self-identified parent gender?; (3) baseline language 
functioning: Do outcomes differ for toddlers who begin the program below (vs. at or above) a 12-
month language level (based on parent-reported CDI scores)?  
 
2.19 Has any pilot study been carried out using this design? 
 
We have made two substantive adaptations to the standard Social ABCs program, each with 
some pilot data. First, we developed a Group-based protocol for didactic learning and shortened 
the duration of 1:1 coaching (6 vs. 12 weeks). We have pilot tested the Group adaptation (n = 45 
in-person families) with positive reports from families and Coaches (see Report to Alva 
Foundation, attached). Preliminary analyses43 reveal significant gains in toddler responsiveness 
and parent fidelity comparable to those for the original model (see Fig. 1 and 2). Unique to the 
Group model is evidence of reduced parenting stress (Fig 3), which highlights the enhanced 
clinical impact of a Group-based intervention that goes beyond increased efficiency28. Parents in 
the Group model also reported improved toddler language (words understood and spoken38 
significantly increased, p’s < .001), reduced toddler autism symptoms (APSI37 scores decreased 
significantly from 20.5 to 17.2; p = .0005), and high satisfaction (33.1 out of a possible 35). 
 
 

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The second key adaptation to our original model involved developing a virtual coaching 
protocol for the Group model. Our team made this additional adaptation in April 2020, in 
response to the Covid-19 pandemic, and we have already piloted this adapted virtual Group 
model with an additional 22 families (and 11 in progress), demonstrating the feasibility and 
promise of this novel approach. Preliminary analyses of the virtual Group-based adaptation 
reveal outcomes similar to the in-person Group model, with comparable gains in parent fidelity 
(from 30.8% to 72.2%; p = .009) and a trend toward reduced parenting stress (from 31.8 to 25.5) 
similar in magnitude to the in-person values. Although child-level video data have not yet been 
coded, parent-reported autism symptoms (on the APSI37) decreased significantly (23.2 to 18.5; p 
= .004), and satisfaction was high (32.5 out of 35). Parent-reported toddler language also 
increased (p’s = .003, .018, respectively for words understood and spoken). On all metrics 
evaluated to date, changes are commensurate across in-person and virtual delivery methods.  
  
The adapted, virtual group delivery model is a promising, innovative and cost-efficient way to 
provide intervention to toddlers with probable or confirmed autism at the first signs of concern.  
 
3. Trial Management 
 
3.1 What are the arrangements for day to day management of the trial?  
 
The team already has procedures in place to facilitate trial management; we have access to a 
senior Research Coordinator (RC), experienced in clinical trials management on multi-site 
intervention trials. She will oversee registration of the trial with clinicaltrials.gov and 
management of cross-site collaboration to ensure consistency and compliance. The central RC 
will assign randomization codes and ensure blinding of videos in preparation for coding. We have 
a full complement of trained Coaches and Research Assistants at each site. Because the project is 
entirely virtual, we do not anticipate any study delays or stoppages related to current or future 
Covid-19 measures. 
  
3.2 What will be the role of each principal applicant and co-applicant proposed? 
 
Nominated Principal Applicant: J Brian PhD is a clinical-developmental psychologist and 
clinician-investigator with extensive expertise in early ASD characterization, family support, and 
intervention. She will lead all aspects of project development, realization, interpretation, and 
knowledge mobilization (2 days/week on this project). Dr. Brian led the cross-site RCT22 of the 
original model, currently co-leads a multi-site attention co-intervention RCT (analyses 
underway), and collaborates on several RCTs investigating pharmacological treatments in autism. 
 

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Co-Applicants: IM Smith PhD (Halifax Lead), psychologist, will oversee and supervise program 
delivery, data collection, and video coding at the Halifax site. She will contribute considerable 
expertise in community-based ASD early intervention research, and will contribute to 
interpretation of study findings and manuscript preparation (.5 day/wk). L Zwaigenbaum MD 
(Edmonton Lead), developmental paediatrician, will oversee and supervise program delivery and 
data collection at the Edmonton site. He has expertise in research design and biostatistics, early 
ASD detection, and community partnerships to facilitate uptake into care. He will contribute to 
statistical analysis, interpretation, and manuscript preparation (.5 day/wk). P Andreou PhD is a 
Biostatistician at Dalhousie University with expertise in clinical trials, sample surveys, and 
statistical modelling. He will be responsible for issues related to trial design, randomization, 
analyses, and interpretation (.5 day/wk at study initiation and year 3 analyses and interpretation). 
 
Collaborators –Knowledge Users (KUs): KU’s represent organizations that currently use or are 
interested in implementing the Social ABCs if the trial shows positive effects, and community 
stakeholders who can advise on implementation considerations. C Roncadin PhD, clinical 
psychologist and Clinical Director ASD services; I Drmic PhD, clinical psychologist in mental 
health and autism (both McMaster Children’s); D Chitty PhD, clinical psychologist and 
Provincial Leader for Nova Scotia (NS) Early IBI, and N Beswick MSc-SLP, Speech Language 
Pathologist/ Clinical Lead Pediatrics; Communication Disorders (Glenrose Rehab, AB. Annual 
stakeholder meetings with KUs, steering committee members, and family advisors will occur 
virtually to review study progress and to advise on implementation factors (e.g., participant flow, 
feedback). See letters of support from additional community stakeholders (attached). 
 
Family Advisors: S Cosgrove and A Zarem, both with considerable experience on family 
advisory boards, will each bring a unique parent perspective to stakeholder meetings, 
interpretation of findings, and idea-generation regarding future wide-scale implementation; one 
family advisor will be invited to join the steering committee. Program Partner: We have secured 
funds from Kids Brain Health Network (KBHN; see partner letter) to support this project (n=30). 
We will leverage these funds to supplement the current proposal and reach our recruitment target.  
Consultation: S Bryson (Professor Emerita, Dalhousie U), program co-developer, will support 
interpretation of findings and manuscript preparation.  
 
3.3 Trial steering committee and data safety and monitoring committee. 
 
The steering committee will consist of J Brian, IM Smith, L Zwaigenbaum, two senior Coaches 
(E Dowds and K Bernardi), and one family advisor, and will meet formally every six months 
throughout the project, with ad hoc meetings as needed. Statistical analyses will be conducted by 
J Brian and L Zwaigenbaum, with consulting support through the University of Toronto (OISE) 
statistical support service. Despite low anticipated risk, we will establish a data safety and 
monitoring board using processes in place in our current work, with members external to the 
conduct of the study: one scientist, one member with biostatistics expertise, and one family 
advisor (different from those named above). This committee will meet twice yearly to review 
enrollment, completion, and withdrawal rates, adherence to the study protocol, protocol violations 
or deviations, any adverse events (which are also reported to our Research Ethics Boards), and 
external factors that might affect the ethics of the study.    
 
 
 

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