Anticipatory postural adjustments in autism

Accuracy in coordinated movement depends on postural control, and also anticipatory behaviour, which enables the individual to predict the outcomes of planned motor action, and thus contributes to the precision in human movement performance. This anticipatory capacity arises through the generation of anticipatory postural adjustments (APAs) or changes in background muscle activity that precedes volitional movement. In autism, impairments in anticipatory mechanisms have been reported in recent research, however, to date, APAs have not been examined in adults with autism. The objective of this study is therefore to quantify APAs in adults with autism spectrum disorders (ASD) compared to IQ-matched neurotypical participants to thus advance knowledge of the neural basis of substantiated motor impairments in autism, specifically in relation to movement coordination. This current study involves analysis of APAs generation via surface electromyography (sEMG) of the biceps brachii, within the framework of a bimanual load-lifting task (BMLL), requiring high-level neuromotor coordination and APAs implementation. In contrast to previous studies of APAs in autism, participants in both the autism and neurotypical groups showed similar, efficient anticipatory postural adjustments to counterbalance the unloading event in the BMLL task therefore suggesting anticipatory mechanisms for predictive motor behaviour is intact in the individuals with autism. These findings thus aid clarification in recent literature concerning anticipatory behaviour in autism.