22063
Effects of Reciprocal Imitation Training on Brain and Behaviour: A Pilot Randomized Controlled Trial
Reciprocal Imitation Training (RIT) is a play-based developmental-behavioural intervention focused on increasing imitation skills and gesture use, developed to address social imitation deficits in individuals with autism. Previous research has demonstrated RIT to be effective for increasing spontaneous object and gesture-based imitation.
Objectives:
The current study is an examination of electroencephalographic (EEG) measures of brain activity as potential biomarkers for these intervention effects, in the context of an external-laboratory replication trial.
Methods:
Participants in this completed Randomized Controlled Trial were 24 children with autism aged 2- to 6-years. An intervention group received 20 sessions of RIT over a period of 12 weeks, relative to a Wait-List control group. Stratified randomization was conducted utilizing pre-defined chronological age and verbal ability criteria at intake. Pre- and post-intervention assessments included the verbal portion of the Mullen Scales of Early Learning, the Autism Diagnostic Observation Schedule, and two experimental-behavioural change measures: Unstructured Imitation Assessment (UIA) and Structured Imitation Assessment (SIA), administered by experimenters who were blinded to intervention status. Event-related potentials were recorded at post-training utilizing a Rapid Auditory Mismatch paradigm for Human versus Non-Human Action Sound Processing previously utilized in our laboratory to study children with and without Autism Spectrum Disorder.
Results:
Behavioral effects of RIT were evaluated using a repeated-measures ANOVA, with post-hoc t-tests further comparing baseline scores with scores after 12 weeks. Children in the intervention group (N = 12; M = 11.08, S.D. = 10.4) made significantly more gains in spontaneous imitation measured via the UIA as compared to children in the wait-list group (N = 12; M = 6.3, S.D. = 9.3), F (1,22) = 8.09, p < .01, ηp2 = .27. Follow-up t-tests on the intervention group data further supported this finding, exhibiting a significant difference between pre-intervention and post-intervention imitation scores, t (11) = -3.1, p = .01. Repeated measures ANOVAs conducted on event-related potentials data recorded over medial central and medial parietal cortex produced interactions of Participant Group (Intervention, Wait-List) by Stimulus (Human, Non-Human) by Congruency (Match, Mismatch) which indicated that children in the Intervention group (N = 8) exhibited larger amplitude responses for human stimuli which were preceded by a non-human stimulus (mismatch) whereas Wait-List participants (N = 7) exhibited larger amplitude responses for human stimuli which were preceded by a human stimulus (match), F (1,13) = 11.45, p < .01, ηp2 = .47 and F(1,13) = 5.59, p=0.02, ηp2= 0.3 for central and parietal components respectively.
Conclusions:
The current findings produced an external-laboratory replication of previous behavioural intervention effects driven by RIT, providing further experimental evidence for the effectiveness of RIT for improving socially interactive imitation during unstructured play. The results of the event-related potentials assessment provide further experimental evidence to suggest that these behavioural effects are associated with increased attentional orienting responses to social stimuli, reflected in increased central and parietal brain activity in response to human sounds which are not predicted from the preceding context.