PEERS Treatment Leads to Increased Neural Activity in Adolescents with ASD

Background:  

The Program for the Education and Enrichment of Relational Skills (PEERS), a 14-week, manualized, empirically-validated treatment, focuses on improving friendship quality, decreasing social isolation, and increasing social skills among adolescents with high-functioning ASD (Laugeson et al., 2009; 2010).  However, few studies to date have examined neurological change or plasticity in ASD due to intervention, even though evidence increasingly highlights the brain-based nature of the disorder.  Plasticity measures would also significantly assist in understanding how and why certain treatments are effective in ASD. Likely candidates for plasticity in ASD include the frontal lobe, a key area of the “social brain” known to contribute to initiation and regulation of social behavior (Adolphs, 1999).  Additionally, measures of continuous electroencephalogram (EEG) activity may be especially well-suited to studying overarching changes in neural activation due to intervention, with gamma band activity (30-45 Hz) of particular interest, as activity in this range has been linked to higher-order cognitive function and synchronized neuronal firing (Miltner et al., 1999), processing of faces (Balconi&Lucchiari, 2008), and response to emotion (Li & Lu, 2009), all of which likely contribute to social behavior.

Objectives:  

The objectives of this study were to examine changes/plasticity in EEG gamma activity, and behavioral correlates of neural change, in adolescents with ASD who underwent PEERS treatment.

Methods:  

Forty 11-15 year-old adolescents with ASD were recruited and randomly assigned to either an Experimental Treatment Group (EXP) or a Waitlist Control Group (WL).Pre- and post-PEERS (pre- and post- a 14-week delay for the WL group) measures included parent report of symptoms of autism, via the Social Communication Questionnaire (SCQ: Rutter, Bailey, & Lord, 2003).  Pre- and post-PEERS continuous EEG activity was collected from adolescents during a 3-minute resting, eyes open condition, using an Electrical Geodesics amplifier and 64-channel net. Artifact-free activity from left (9, 10/FP1, 11, 12/F3, 13, 17, and 18/F7) and right frontal hemisphere (1, 2, 3, 5/FP2, 58/F8, 59, and 60/F4) electrodes was epoched and averaged in the spectral domain using a Fourier transform in Neuroscan Edit 4.5, with gamma activity defined as 30-45 Hz. 

Results:  

Preliminary results include available data from the EXP group(n = 10).  A significant time x hemisphere interaction, F (1, 9) = 10.238, p<  .05, partial eta² = .53, indicated that both left and right frontal hemisphere gamma power increased from pre- to post-treatment, with more dramatic increases in left versus right hemisphere. Increases in left and right frontal EEG gamma activity after PEERS were significantly associated with parent-report of fewer autistic symptoms on the SCQ at post-treatment, r = -.63, p< .05.

Conclusions:  

Initial results suggest that adolescents who complete PEERS intervention show evidence of increased higher-order neural activity in the frontal lobe.  An increase in frontal lobe activity was also associated with fewer symptoms of autism at post-treatment. Ongoing analyses will include additional participants in the EXP group, add the WL group data, and analyze additional data from other cortical sites, frequency bands, and EEG connectivity (coherence).