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Comparing fNIRS-Based Cortical Activation Patterns during Communicative Gestures between Children with and without Autism Spectrum Disorder (ASD)
Children with Autism Spectrum Disorder (ASD) have difficulty using communicative gestures with others. In this study, we investigated the neural mechanisms underlying this gestural impairment. Specifically, we examined the activation within the Mirror Neuron Systems (MNS) including the inferior frontal gyrus (IFG), superior temporal sulcus (STS), and inferior parietal lobule (IPL). Past studies have used fMRI to study gesture control in relatively unnatural contexts (within a scanner bore facing 2D displays). Functional near-infrared spectroscopy (fNIRS) is a neuroimaging tool that allows for more naturalistic, face to face gestural communication between people.
Objectives:
In this study, we compared MNS activation between children with and without ASD as they observed of performed communicative gestures with an adult partner.
Methods:
Fifteen children with ASD and 16 typically developing children with ASD between the ages of 6 and 17 years wore an fNIRS cap embedded with 3x3 probe sets covering bilateral MNS regions including the inferior parietal, superior temporal and inferior frontal cortical gyri. Each child was seated across from an adult social partner. The gestural task involved 3 conditions completed using a randomized block design: a) Watch (W): child observed adult’s gestures, b) Do (D): child performed a gesture on their own c) Together (T): child performed the gesture in synchrony with the adult. 18 trials were collected, 6 per condition using a randomized blocked design. The oxy-hemoglobin response was analyzed to study differences between groups, tasks, hemispheres, and regions.
Results:
In terms of group differences, children with ASD had lower activation in the Left IFG and STS regions than the TD children, mainly for the Do/solo action condition. In contrast, children with ASD showed greater activation in the right IFG and both PI regions compared to the TD children, mainly for the Watch/observe and Together/synchrony conditions. In terms of hemispheric differences, the TD children showed greater cortical activation in the left inferior frontal and superior temporal regions compared to the right homologues for these unilateral tasks. In contrast, children with ASD had symmetrical activation across multiple ROIs even though the tasks were unilateral in nature.
Conclusions:
Children with ASD showed reduced cortical activation in the superior temporal cortices and in contrast showed greater cortical activation in the right inferior frontal and inferior parietal cortices compared to TD children. Children with ASD lack the left lateralized pattern of cortical activation clearly seen in the TD children during unilateral tasks. Multiple neurobiomarkers associated with gestural communication were obtained and seemed atypical in the children with ASD. In the future, we hope to test intervention contexts to facilitate gestural communication and normalize activation patterns in children with ASD.