O-19 Impact of attentional abilities on step initiation in healthy people: An EEG study

Abstract

Background Step initiation can vary according to attentional resources. Components of visuospatial attention (alerting, orienting, and executive control or conflict resolution) have shown to be able to modulate specifically anticipatory postural adjustments (APAs) and step execution phase, and can be assessed simultaneously within a single paradigm: the “Attention Network Test” (ANT). The present study aims to a better understanding of the interaction between visuospatial attention and step initiation in a healthy population through the observation of: (1) the modulation of step initiation while performing the ANT and (2) the potential modifications of cortical motor preparation. Material and methods Thirty-two healthy subjects performed an attentional task adapted from the ANT and combined with step initiation. Cortical activity during movement preparation (APA) and execution was assessed via high-resolution encephalography. Results Step initiation was particularly perturbed in conflict resolution condition. Conflict resolution also affected event-related spectral perturbations (ERSPs) in alpha and beta bands: movement-related desynchronization over the sensorimotor cortex occurred earlier and was longer and of higher amplitude after response to a target with incongruent flankers. Conclusions Tasks with attentional load such as conflict resolution lead to an alteration of step initiation and concomitant modifications of ERSPs during APAs. The ANT combined with step initiation could be therefore used to better understand pathologies such as Parkinson’s disease with gait akinesia.