Biology subjects

Lambrecht, E.

Publications and source records attributed to Lambrecht, E..

2 recordsLinked to original sources

bioRxiv2026

Aging impairs control of center of mass during repeated visual perturbations in walking

Sensory degradation with aging can impair balance control, partly by disrupting visual contributions to self-motion estimation. We investigated age-related differences in center of mass (CoM) trajectories controlling in the frontal plane during exposure to repeated visual perturbations in walking. We hypothesized that the older adults would show larger responses to visual perturbations and less adaptation to repeated visual perturbation exposure. We applied three visual perturbations to 14 healthy older (age: 75.0{+/-}2.4) and 16 younger adults (age: 23.4{+/-}3.9) walking on a treadmill: fixating a stationary target with the background moving to the right (MB), tracking a target moving rightward over a stationary background with head rotation (MT-HR), and tracking a moving target with eye movement only (MT-EM). CoM position deviations due to the visual perturbations were assessed. Over the whole trial, the older adults did not show larger CoM position variability than the younger during visual perturbation walking, which was contrary to our hypothesis. During visual perturbation epochs, both age groups deviated in the same direction except MB. In MB, the older adults deviated to an opposite direction after a few perturbation repetitions. Moreover, in MT-HR and MT-EM, the older adults deviated earlier than the younger adults and they deviated more in the MT-HR condition. This indicates that older adults exhibit reduced ability to accurately estimate self-motion through correction by other sensory modalities when exposed to visual perturbations. Over repeated perturbations, the older adults showed decreased CoM deviations in MT-EM, which suggests that they still maintain the capacity to downweight visual information after repeated exposure.

neuroscience↗

bioRxiv2025

The Impact of Visual Perturbations on Balance Control during Walking

Visual perturbations may lead to an illusory self-motion and affect balance control. We studied effects of different visual perturbations in 16 healthy young participants walking on a treadmill, by assessing foot placement and center of mass (CoM) states. Three different visual perturbations were applied: fixating on a stationary target while the background moved to the right (MB), tracking the target moving rightward over a stationary background with head rotation (MT-HR), and tracking the moving target with eye movement only (MT-EM). Deviations of foot placement, CoM and trunk orientation due to the visual perturbation were assessed. Linear models were fit to the kinematic data to predict foot placement from CoM state at mid-swing. Over the whole trial, MT-HR and MT-EM caused an increase in step width variability, CoM position variability and RMS of foot placement errors simultaneously. During visual perturbation epochs specifically, in MB, a left deviation of foot and CoM trajectories was observed from the start of the background movement. In MT-HR and MT-EM, a right deviation of foot and CoM trajectories was observed only after the target had stopped moving. Contrary to our expectations, foot placement errors did not coincide with subsequent CoM deviations in the opposite direction. An obvious change in frontal plane trunk orientation was found only in MT-HR. While all visual perturbations affected control of the CoM trajectory in the frontal plane, these effects appeared caused by effects on control of heading as well. Head rotation appears to additionally disturb balance through a coupling with trunk orientation. Summary statementVisual perturbations during walking alter foot placement and body motion in humans, revealing how eye and head movements influence walking balance.

neuroscience↗