Effects of Early Social-Communicative Intervention on the Brain Activity of Toddlers with ASD: An ERP Study.

Poster Presentation
Thursday, May 2, 2019: 5:30 PM-7:00 PM
Room: 710 (Palais des congres de Montreal)
A. Piatti, S. Van der Paelt, P. Warreyn and H. Roeyers, Department of Experimental-Clinical and Health Psychology, Ghent University, Ghent, Belgium

There is large consensus that objective and insightful evaluations of autism interventions should include neurophysiological measures.


This randomised controlled trial tests the effects of Project ImPACT, an early parent-run intervention targeting social-communicative skills, on the behaviour and brain activity of toddlers with Autism Spectrum Disorder (ASD).


Toddlers with ASD have been randomised to receive either Project ImPACT or treatment as usual (TAU), which does not specifically focus on social-communicative abilities. Researchers involved in data acquisition and analysis were blind to group assignation. Outcome measures include event related potentials (ERPs) in response to standard and deviant voice and non-voice stimuli.

The ImPACT (n=12, 1 girl, mean age: 3.1 ±.6, mean IQ: 62.67 ± 24.42) and TAU groups (n=8, 1 girl, mean age: 3.5 ±.5, mean IQ: 59.38 ± 22.5) were compared at baseline and outcome separately to typically developing (TD) children (n=16, 4 girls, mean age: 3.0 ±.9) in the P1, N2, P3 and N4 time windows. Sample size will increase to n = 20 or higher per group before the INSAR meeting. A 2 X (voice/non-voice standard sound) X 2(voice/non-voice deviant sound) X 2 (group) interaction was tested using permutation-based t-test (n=5000) over differences between levels and between factors. Time was added as a two-level factor when comparing ImPACT and TAU.


This section highlights the most prominent findings of this study (complete overview in Table 1).

A significant main effect of group was found over N2 mean voltages when comparing the ImPACT group at baseline and the TD group (t(1,26) = 1.849, p = .031), as well as the TAU group at baseline and the TD group (t(1,22) = 1.759, p = .048).

For the ImPACT group, the difference with TD became non-significant after the intervention (t(1,26) = .576, p = .279). For the TAU group, the difference with TD was still significant after the intervention (t(1,22) = 1.937, p = .033). A paired samples t-test within the ImPACT group confirmed the effect of treatment on the N2 component (t(1,11) = 3.256, p =.005), which became less negative (Figure 1).

The differential effect of intervention over the N2 response to deviant stimuli was further supported by the time X group interaction approaching significance when comparing the ImPACT and TAU groups (t(1,18) = 1.412, p = .085).

Exploratory analysis suggests that a larger N2 in children with ASD correlates with worse response to joint attention (r = .442 [.017 767], p =.049). We will further investigate whether the treatment effect on the N2 ERP component is associated with improved response to joint attention.


Initial group differences, as well as treatment effects, were mostly observed on the N2 ERP component. A larger N2 response at baseline in children with ASD may reflect hypersensitivity to sound change or a more effortful attentional disengagement, with possible repercussions on the children’s social behaviour. These preliminary results suggest a deeper effect of early intervention focused on social-communicative skills training compared to intervention that does not primarily focus on social communicative abilities.