People make anticipatory changes in gait patterns prior to initiating a rapid change of direction. How they prepare will change based on their knowledge of the maneuver. To investigate specific and general strategies used to facilitate locomotor maneuvers, we manipulated subjects’ ability to anticipate the direction of an upcoming lateral “lane-change” maneuver. To examine specific anticipatory adjustments, we observed the four steps immediately preceding a maneuver that subjects were instructed to perform at a known time in a known direction. We hypothesized that to facilitate a specific change of direction, subjects would proactively decrease margin of stability in the future direction of travel. Our results support this hypothesis: subjects significantly decreased lateral margin of stability by 69% on the side ipsilateral to the maneuver during only the step immediately preceding the maneuver. This gait adaptation may have improved energetic efficiency and simplified the control of the maneuver. To examine general anticipatory adjustments, we observed the two steps immediately preceding the instant when subjects received information about the direction of the maneuver. When the maneuver direction was unknown, we hypothesized that subjects would make general anticipatory adjustments that would improve their ability to actively initiate a maneuver in multiple directions. This second hypothesis was partially supported as subjects increased step width and stance phase hip flexion during these anticipatory steps. These modifications may have improved subjects’ ability to generate forces in multiple directions and maintain equilibrium during the onset and execution of the rapid maneuver. However, adapting these general anticipatory strategies likely incurred an additional energetic cost.

People with incomplete spinal cord injury (iSCI) expend considerable energy to walk, which can lead to rapid fatigue and limit community ambulation. Selecting locomotor patterns that enhance lateral stability may contribute to this population’s elevated cost of transport. The goal of the current study was to quantify the metabolic energy demands of maintaining lateral stability during gait in people with iSCI. To quantify this metabolic cost, we observed ten individuals with iSCI walking with and without external lateral stabilization. We hypothesized that with external lateral stabilization, people with iSCI would adapt their gait by decreasing step width, which would correspond with a substantial decrease in cost of transport. Our findings support this hypothesis. Subjects significantly (p < 0.05) decreased step width by 22%, step width variability by 18%, and minimum lateral margin of stability by 25% when they walked with external lateral stabilization compared to unassisted walking. Metabolic cost of transport also decreased significantly (p < 0.05) by 10% with external lateral stabilization. These findings suggest that this population is capable of adapting their gait to meet changing demands placed on balance. The percent reduction in cost of transport when walking with external lateral stabilization was strongly correlated with functional impairment level as assessed by subjects’ scores on the Berg Balance Scale (R = 0.778) and Lower Extremity Motor Score (R = 0.728). These relationships suggest that as functional balance and strength decrease, the amount of metabolic energy used to maintain lateral stability during gait will increase.

In CLN3 disease, impairments in motor function are frequently reported to have later onset compared to visual and cognitive decline, but upper limb motor function has yet to be explored in this population. In a cohort of 22 individuals with CLN3, we used a novel application of multiple measures to (1) characterize motor function, particularly of the upper limbs, in activities of daily living (ADLs), and (2) explore associations between motor function and age as well as visual ability, disease severity, and cognitive function, as evaluated by the Unified Batten Disease Rating Scale (UBDRS), a validated CLN3 disease measure. ADLs that required coordination, speed, and fine motor control were particularly challenging for children with CLN3 based on item‐level performance across direct assessments (Jebsen–Taylor Hand Function Test [JTHFT] and MyoSet Tools) and caregiver reports (Pediatric Evaluation of Disability Inventory‐Computer Adaptive Testing [PEDI‐CAT] and Patient‐Reported Outcomes Measurement Information System [PROMIS] Pediatric Upper Extremity). Poorer visual ability, disease severity, and cognitive function were associated with worse performance on these measures, whereas age had limited impact. These findings support the need for children with CLN3 to receive skilled clinical evaluation and treatment tailored to their individual needs, particularly in the context of ADLs, as their symptom profile progresses.