Pivotal Response Treatment Alters Brain Function in Children with Autism

Background:  

Autism Spectrum Disorder (ASD) is characterized by severe deficits in social information processing (Levy, Mandell, & Schultz, 2009), which are most visible in natural social settings (Volkmar et al., 2004). Pivotal response treatment (PRT) is a naturalistic behavioral intervention that promotes social communication development in children with ASD. Although PRT is an empirically validated treatment, the neural and behavioral mechanisms by which PRT is efficient are lacking. 

Objectives:  

We aim at identifying neural and behavioral mechanisms of PRT related improvements in the social functioning of children with ASD using well-validated eye-tracking and fMRI paradigms. 

Methods:  

We are randomly assigned 4- to 6-year-old children with ASD (N=20) to either a waitlist control group (WTC, n=10) or the PRT group (n=10). Additionally, we include typically developing children (TD, n=20, matched for age, sex and IQ) as a point of reference for the interpretation of changes in brain function and visual scan paths. All children are assessed twice, at time 1 (T1) and time 2 (T2) separated by a four-month interval, during which the PRT group receives treatment. 

Results:  

Preliminary eye-tracking data from 8 children with ASD (6 males) pre and post PRT indicates that at T2, the proportion of fixations on the mouth region significantly increases, relative to T1. FMRI analysis including 10 children with ASD (9 male) at T1 yields activity of the right fusiform gyrus, and the bilateral lateral occipital cortex for faces vs. houses. Analysis of treatment effects (T2 > T1) reveals significant increases in activity in the medial prefrontal cortex (MPFC) for social stimuli (faces vs. houses) in PRT (n=5) vs. WTC (n=5) group. 

Conclusions:  

Preliminary analyses of PRT-related effects indicate that the treatment modulates behavior and brain function. In particular, the MPFC has been closely linked to consciously engaging in social cognition (e.g., taking another’s perspective into account (Amodio & Frith, 2006)). Increased activity in the MPFC after treatment might underlie the positive effects of PRT on social behavior.