Biology subjects

Brodie, M. A.

Publications and source records attributed to Brodie, M. A..

2 recordsLinked to original sources

bioRxiv2025

Foot placement coordination is impaired in people with Parkinson's Disease

BackgroundGait instability is a common and disabling symptom of Parkinsons disease (PD), contributing to frequent falls and reduced quality of life. While clinical balance tests and spatiotemporal gait measures can predict fall risk, they do not fully explain the underlying control mechanisms. In healthy individuals, foot placement is actively adjusted based on an internal estimate of the center of mass state to maintain gait stability, known as foot placement control. This estimation relies on the integration of multisensory information, which has been shown to be impaired in PD, potentially disrupting the control of gait stability through foot placement. ObjectiveTo investigate whether foot placement coordination during overground walking is impaired in people with PD. MethodsFifty people with PD and 51 healthy older adults walked overground for ten minutes at self-selected, comfortable walking speed. Foot placement errors were quantified as the deviation between the actual foot placement and the predicted placement derived from the center of mass kinematic state during the preceding swing phase. ResultsFoot placement errors were significantly higher in people with PD than in healthy older adults in both mediolateral (p < .05) and anteroposterior directions (p < .0001), at both mid-swing and terminal swing. Relative explained variance in mediolateral direction was significantly higher in people with PD compared to healthy older adults (p < .005). ConclusionWe provide first evidence of impaired coordination between the center of mass and foot placement in PD. Future work should investigate a causal relationship between impaired foot placement control, sensorimotor integration and gait instability.

pathology↗

bioRxiv2018

Exposure to unpredictable trips and slips while walking can improve balance recovery responses with minimum predictive gait alterations

INTRODUCTIONThis study aimed to determine if repeated exposure to unpredictable trips and slips while walking can improve balance recovery responses when predictive gait alterations (e.g. slowing down) are minimised.\n\nMETHODSTen young adults walked on a 10-m walkway that induced slips and trips in fixed and random locations. Participants were exposed to a total of 12 slips, 12 trips and 6 non-perturbed walks in three conditions: 1) right leg fixed location, 2) left leg fixed location and 3) random leg and location. Kinematics during non-perturbed walks and previous and recovery steps were analysed.\n\nRESULTSThroughout the three conditions, participants walked with similar gait speed, step length and cadence(p>0.05). Participants extrapolated centre of mass (XCoM) was anteriorly shifted immediately before slips at the fixed location (p<0.01), but this predictive gait alteration did not transfer to random perturbation locations. Improved balance recovery from trips in the random location was indicated by increased margin of stability and step length during recovery steps (p<0.05). Changes in balance recovery from slips in the random location was shown by reduced backward XCoM displacement and reduced slip speed during recovery steps (p<0.05).\n\nCONCLUSIONSEven in the absence of most predictive gait alterations, balance recovery responses to trips and slips were improved through exposure to repeated unpredictable perturbations. A common predictive gait alteration to lean forward immediately before a slip was not useful when the perturbation location was unpredictable. Training balance recovery with unpredictable perturbations may be beneficial to fall avoidance in everyday life.

physiology↗