People without stroke used explicit audiovisual cues to proactively modify lower-extremity work and improve subsequent stability during gait perturbations, whereas people post-stroke did not use the cues to update their control strategy, instead relying on a general reactive control strategy regardless of perturbation predictability.
Key Findings
Results
Following unexpected treadmill accelerations, both people with and without chronic stroke had smaller margins of stability on the recovery step compared to unperturbed walking.
Both groups were tested on single-belt treadmill accelerations as gait perturbations
Margins of stability were measured on the recovery step following perturbations
This finding held for both the stroke and neurotypical groups, indicating a shared baseline reactive response
The perturbations spanned a continuum from fully unexpected to predictable based on explicit audiovisual cues
Results
People without stroke performed less leg and joint work, especially at the ankle, during cued perturbations compared to uncued perturbations.
Audiovisual cues specified the impending perturbation step explicitly
Reductions in work were observed at the leg level and specifically at the ankle joint
This proactive reduction in push-off work occurred when participants knew the perturbation was coming
The adjustment reflects a proactive control strategy in response to predictive cuing
Results
People without stroke increased their margins of stability by approximately 3 cm on the recovery step when audiovisual cues were provided.
The increase in margin of stability was approximately 3 cm (~3 cm) on the recovery step
This improvement occurred specifically when audiovisual cues specifying the impending perturbation step were given
The improvement was associated with the proactive reduction in ankle and leg work during the perturbation step
This demonstrates that neurotypical individuals effectively translate predictive cue information into improved balance outcomes
Results
People post-stroke did not make the same proactive adjustments as neurotypical individuals when given audiovisual cues about impending perturbations.
Despite receiving explicit audiovisual cues specifying the timing and nature of the perturbation, people post-stroke did not modify their lower-extremity work proactively
The lack of proactive adjustment was observed even though cues provided precise timing information about the impending gait perturbations
This failure to update control strategy was attributed to a combination of motor and cognitive impairments resulting from brain lesions
The finding held regardless of perturbation predictability, suggesting cue information was not effectively integrated into motor planning
Results
After any perturbation, people post-stroke modified their stepping to maintain their center of mass position within their base of support, and this strategy remained unchanged with audiovisual cues.
People post-stroke used a reactive stepping strategy to keep the center of mass within the base of support following perturbations
This general control strategy was employed after both unexpected and cued perturbations
The strategy did not change with the introduction of audiovisual cues, indicating an inability or failure to shift from reactive to proactive control
The authors describe this as reliance on 'a general control strategy rather than proactively modifying push-off work'
Discussion
The inability of people post-stroke to use predictive cues to update their gait control strategy may contribute to their fall risk during predictable balance challenges.
The authors explicitly link the failure to implement proactive adjustments to fall risk in people post-stroke
Predictable balance challenges in daily life (e.g., known terrain changes) would normally afford opportunity for proactive control
Stroke-related motor and cognitive impairments are proposed as the mechanism underlying the impaired proactive control
The findings suggest that rehabilitation strategies targeting proactive balance control may be relevant for stroke survivors
What This Means
This research suggests that after a stroke, people lose the ability to prepare for a balance challenge even when they are told it is coming. In the study, participants walked on a treadmill that could suddenly speed up, throwing off their balance. When non-stroke participants were given a warning cue (a light or sound) before the treadmill sped up, they automatically adjusted how hard they pushed off with their feet — particularly at the ankle — and as a result they recovered their balance about 3 centimeters more effectively than when the disturbance was unexpected. Stroke survivors, however, made the same reactive stepping response whether or not they received the warning cue, meaning the advance information did not change how they moved.
This matters because in everyday life, many balance challenges are at least partially predictable — stepping off a curb, walking on a moving bus, or navigating a known uneven surface. Non-stroke individuals naturally use such predictive information to prepare their bodies before the challenge occurs, which helps prevent falls. This research suggests that people who have had a stroke may not be able to apply this kind of anticipatory adjustment, even when given clear and explicit information about what is about to happen. This could help explain why stroke survivors remain at high fall risk even in familiar or predictable environments.
The findings point toward a potentially important gap in current stroke rehabilitation: training programs may need to specifically target the ability to use advance information to modify movement, rather than focusing only on reactive recovery from unexpected falls. Understanding why stroke survivors default to reactive rather than proactive balance strategies — whether due to motor weakness, cognitive changes, or both — could help guide more tailored approaches to fall prevention after stroke.
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Cornwell T, Finley J. (2026). Proactive adjustments to cued gait perturbations in people with and without chronic stroke.. Journal of neurophysiology. https://doi.org/10.1152/jn.00521.2025