Robot-based assessment of motor-cognitive dual-task abilities in unimpaired adults

The addition of a cognitive task to a balance task impacts postural control. While the effects of dual-tasks on the ability to maintain an upright posture in static conditions or during walking have been extensively investigated, a limited number of studies focused on dynamic balance scenarios. Even fewer studies have examined such scenarios while sitting. In this work, we explored how a motor-cognitive dual-task influenced balance in unimpaired individuals, in two age groups, under three different balance conditions while sitting. Subjects sat on a moving robotic seat that was either static, unstable as a plate on a pivot, or tilted following a preprogrammed motion trajectory. Subjects completed the single balance tasks, and the balance tasks plus both a digital version of the Stroop Test and a simple reaction time test, both administered using the robotic device's touchscreen. Since the Stroop test required active interaction with the screen, the reaction time test was included to determine whether the expected decline in balance performance during the cognitive task was solely due to cognitive load or also influenced by physical interaction with the screen. The study showed that, as expected, the cognitive task worsened balance performance, as shown by increased trunk movements. This effect was significant in all balance conditions except when the platform was moved following a preprogrammed trajectory. Meanwhile, the physical interaction with the screen did not significantly impact balance performance. Future studies will further investigate the dualtask paradigm by incorporating additional cognitive tasks and evaluating balance also while standing.