Considerable evidence attests to a relationship between executive function and falls. Notable among cognitive elements related to fall risk is the ability to suppress a highly automatic but unwanted action—that is, response inhibition. Although the ability to stop may seem like an unlikely foundation for maintaining balance, there are many situations in daily life where the ability to adapt planned action is critical to reducing instability. Most of what we know about the role of inhibition in balance control is based on correlations between cognitive test performance and self-reported falls, leaving a sizable gap in understanding mechanisms linking inhibition and balance control. Here, we expand from traditional balance assessments that accentuate reflexive action and instead impose a need to suppress a prepotent balance recovery step. We leveraged techniques developed in cognitive neuroscience to expose neuromuscular events leading to successful inhibition. Specifically, we used high-density electroencephalography to measure neural markers previously shown to predict successful inhibition in seated voluntary reaction tasks using hand responses (ß-bursts) and applied this to a balance recovery step task. Contrary to our hypothesis, higher ß-burst volume after a stop cue was associated with failed step suppression. Other ß oscillation characteristics revealed slightly earlier ß-burst onsets in successful suppression trials and higher average ß power prior to the stop signal for successful versus failed stop trials. The current study offers insight into potential key markers underlying suppression of a recovery step, and we highlight unique challenges associated with studying cognitive processes during rapid, whole-body balance recovery.
Background Research shows compensatory balance responses can be improved with training. The present study is a coincidental finding from a registered report that provides insight into trainability of response inhibition in a balance recovery stepping task. Research question Can suppression of response inhibition in a rapid balance recovery step be improved with training? Methods Young, healthy participants (N = 20) were released from a supported, forward lean to prompt a rapid balance recovery step. In most trials, participants were instructed to recover balance by quickly stepping forward (i.e., GO trials). However, in 20 % of the trials, a high-pitch tone was randomly played immediately after postural perturbation, signaling participants to suppress a step and relax into a catch harness (i.e., STOP). This balance recovery task was repeated on two separate days. Force plates measured GO reaction time post-perturbation and stepping errors on STOP trials. Results Task performance improved on the second day of testing, including faster steps (321 ± 37 ms vs. 348 ± 40 ms; p < 0.001) and more successful inhibition (46 ± 19% vs. 36 ± 19%; p = 0.005). Also, stop signal reaction time was faster on day two (286 ± 41 ms vs. 308 ± 46 ms; p = 0.041), suggesting the cognitive ability to suppress a highly prepotent action was directly influenced. Significance Our results build from past studies where balance reactions improve with practice and we now demonstrate that outright action cancellation within a balance recovery stepping task can be trained, suggesting behavioral flexibility can be improved without compromising response speed.