Comparing fNIRS-Based Cortical Activation Patterns Between Children with and without Autism, during Transitive and Intransitive Gestures

Background: Children with Autism Spectrum Disorder (ASD) have significant impairments during gestural performance including errors during tool use, pantomime, and meaningless actions. Children with ASD had more errors during meaningless gestures compared to tool use or pantomime tasks; perhaps due to lack of a clear context (Smith & Bryson, 2007). Atypical perception-action couplings during early development in the children with ASD may impair one of the following processes represented within the Mirror Neuron Systems (MNS) and the sensori-motor systems: a) gesture perception involving temporal cortices, b) storage or transcoding of learned gestural sequences in the inferior parietal or frontal cortices and/or d) execution of motor programs by the primary motor cortices (Dowell et al., 2009).

Objectives:  In the current study, we compared MNS and sensori-motor activation during three gestural tasks - object use, pantomime, meaningless.

Methods:  12 children with and without ASD between 6 and 12 years of age and 12 healthy adults were seated at a table with a hammer and pegboard. The task involved holding a hammer and hitting eight pegs on a pegboard in 3 ways: a) Holds hammer: the child hit the pegs with an actual hammer, b) Pantomimes: the child pretends to do the same hammering action, and c) Meaningless: the child performs air tapping. 24 trials were collected, 8 per condition using a randomized block design. The oxy hemoglobin response of the fNIRS signal was further analyzed to study differences in activation patterns between tasks, between hemispheres, and between the regions of interest (temporal, inferior frontal and parietal).

Results: Our preliminary data suggest greater cortical activation during the meaningless condition compared to pantomime or tool use conditions within the inferior parietal and inferior frontal cortices. We did not notice clear patterns in terms of hemispheric or regional differences.

Conclusions: Differences in MNS and sensori-motor cortex activation across gestural tasks will help explain the differing cortical contributions. In terms of intervention implications, our findings may support the notion of providing a clear context to aid successful completion of transitive gestures in children with ASD.