Exploring the Relationship between Postural Control and Brain Activity using Dual-Task Methodology

Understanding how attention is allocated during a balance task, when paired with competing cognitive tasks, can be used to develop therapeutic protocols for elderly individuals as well as those with particular disease conditions requiring a higher efficacy of balance control. Using dual-task methodology, a balance task was paired with a cognitive distractor task. Attention tradeoff between the two tasks was monitored using functional near-infrared spectroscopy (fNIRS), which measured oxygen utilization in various regions of the brain to determine how oxygen use patterns varied in single and dual-tasks. It was hypothesized that participants will prioritize balance/posture and cognitive task scores will drop, and that this performance pattern will be associated with particular patterns of frontal lobe oxygen utilization that can be detected with fNIRS. There were three test conditions, all while the subjects stood. The first condition was a cognitive task that required subjects to listen and identify the number of times they heard the ‘probe’ sound. The second condition was a balance control task that required the participant to sway about the ankles in response to light vibration applied to the abdomen and lower back. If the participant accurately responded to the vibration by swaying either forward or backward, they followed the programmed pattern. A sensor determined the subject’s error of movement. The third condition combined the two tasks. It was found that the dual-task condition resulted in extreme decline of cognitive task accuracy, suggesting that the balance task was prioritized in the non-threatening environment of the study.