Neurophysiological markers of cognitive workload under altered gravity conditions using a gamified dual-task paradigm

Astronauts must maintain optimal cognitive function to complete critical tasks in demanding environments. However, stress and workload can impair executive functions and decision-making, which may ultimately affect mission success. To evaluate workload management the study investigated behavioural data (Reaction Time and Error Rate), as well as neurophysiological parameters (event-related potentials and electrocortical activity) during a continuous primary task combined with an auditory oddball paradigm as a secondary task. Data were collected across Earth gravity, hypergravity (1.8 G), and weightlessness in 25 consecutive parabolas through parabolic flights. Electrocortical activity and performance on the primary task showed no differences between gravity levels. However, the response to target stimuli in the secondary task in microgravity showed a significant increase in the error rate compared to hypergravity and normal gravity. Electrophysiological data showed a pronounced N100-P200 complex, indicating perception-related processing of the oddball paradigm sound. The typical fronto-central N200 component was triggered by both sounds of the oddball paradigm, although no differences were observed between the gravity levels. The absence of a P300 component which is an indicator of higher cognitive processing, suggests that most cognitive resources were devoted to the primary task, reducing the discrimination of the auditory stimuli. Furthermore, the presence of the N200 component, interpreted as the mismatch negativity (MMN), indicates automatic neural responses to auditory deviations that are independent of cognitive load. These findings emphasise that cognitive bottlenecks can arise easily in demanding operational environments, where cognitive resources are limited. Effective task prioritisation and training-based automation are therefore essential for sustaining performance during human spaceflight. Given the substantial variability across individuals, personalised workload-management strategies may be crucial for ensuring focus, timely decision-making, and mission safety. Further research is needed to explore cognitive workload management in such demanding environments.