Pilot Randomized Controlled Trial of the Effects of Reciprocal Imitation Training on Children with Autism

Background: Children with autism exhibit pervasive social and communication difficulties, including particular deficits and delays in social imitation skills.  Reciprocal Imitation Training (RIT) is a play-based behavioural intervention focused on increasing imitation skills and gesture use in individuals with autism.  Previous research has demonstrated RIT to be effective for increasing spontaneous object and gesture-based imitation. However, a limitation in existing literature includes independent replication of effectiveness of intervention outside the parent lab. 

Objectives: The current study is an attempted replication of the previous behavioural effects, as well as an examination of electroencephalographic (EEG) measures of brain activity as potential biomarkers for intervention effects. 

Methods: Participants to date in this on-going Randomized Controlled Trial are 17 children with autism aged 2- to 6-years.  Participants in the intervention group receive 20 sessions of RIT over a period of 12 weeks, relative to a Wait-List control group.  Stratified randomization is conducted utilizing pre-defined chronological age and verbal ability criteria at intake.  Pre- and post-intervention assessments include the verbal portion of the Mullen Scales of Early Learning, Autism Diagnostic Observation Schedule, and two experimental-behavioural change measures: Unstructured Imitation Assessment (UIA) and Structured Imitation Assessment (SIA), administered by experimenters who are blinded to intervention status.  EEG assessments of auditory and visual human versus non-human action processing are also recorded at pre- and post-training. 

Results:   To date, we have analyzed data from the Unstructured Imitation Assessment.  The effect of the intervention was evaluated using repeated-measures ANOVA including Condition (Immediate Intervention, Wait-List) as a between-subjects factor and Time (Pre, Post) as a within-subjects factor. A significant Condition by Time interaction showed that children in the Immediate Intervention group (N = 9; pre-intervention M = 5.4, S.E. = 2.1; post-intervention M = 13.6, S.E. = 3.6) made significantly more gains in spontaneous imitation compared with children in the Wait-List group (N = 8; pre-intervention M = 7.9, S.E. = 3.1; post wait-list M = 6.8, S.E. = 3.8), F (1,15) = 8.47, p = .01, η_p²= .36. Follow-up t-tests on the intervention group data also supported this finding, where a significant difference between pre-intervention scores and post-intervention imitation was observed, t (9) = 3.73, p <.01. Preliminary results from an event-related potentials assessment of human versus non-human action sound processing will also be presented.

Conclusions: The current results suggest that children who received RIT showed significant improvements in spontaneous imitation during play with an unfamiliar adult, compared with children who were in a wait-list control group. Because reciprocal imitation of the actions of others in unstructured contexts is considered to be a core deficit that impacts negatively upon socialization and learning in this population, the results of this study are very encouraging.  Although this study is on-going and the results preliminary at this point, these findings provide further support for RIT as an effective intervention for teaching critical social imitation skills to this population.  Preliminary results from the ERP assessments of this study will provide an initial assessment of potential biomarkers for the observed intervention effects.