Oates Alison

Publications (3) View all

• Article: Control of dynamic stability during adaptation to gait termination on a slippery surface.

  Alison R Oates, James S Frank, Aftab E Patla
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  ABSTRACT: An unexpected slip during gait termination results in a generalised slip response designed to regain stability and prevent a fall. With knowledge of and experience with a slippery surface, locomotor behaviour adapts to proactively diminish the effect of the slip and improve the reactive control during the slip. Our purpose was to examine the organisation of the adaptation to a slippery surface during gait termination. After receiving an unexpected slip during gait termination, participants (N = 8) experienced cued gait termination trials in which they were given knowledge of the surface characteristics (i.e., slippery or non-slippery). The observed strategy used to repeatedly stop on a slippery surface involves proactively diminishing the size of the slip perturbation through a flattened foot at heel contact, anterior shift of the COM, shorter step, stance leg extension and swing limb slowing, as well as improving the reaction to the slippery surface through decreased muscle activity and an appropriate decrease in the braking force generation. The implications of this research are that a combination of knowledge of and experience with a slippery surface enables proactive and reactive adjustments in behaviour to effectively and more safely stop walking on a slippery surface.
  Experimental Brain Research 10/2009; 201(1):47-57. · 2.39 Impact Factor
• Article: Control of dynamic stability during gait termination on a slippery surface in Parkinson's disease

  Alison R. Oates PhD, Jim S. Frank PhD, Aftab E. Patla PhD, Karen VanOoteghem BSc, PhD Fay B. Horak PT, Alison R. Oates, Jim S. Frank, Aftab E. Patla, Karen VanOoteghem, Fay B. Horak
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  ABSTRACT: This study investigated how Parkinson's disease (PD) affects the ability to switch from locomotion to gait termination (GT) during planned and cued GT and examined the effect of PD on the integration of a reactive, balance maintenance strategy into voluntary GT. After a series of stops on a stable surface, eight participants with and 10 without PD stopped on a surface, which slid quickly and unexpectedly forward mimicking a slippery surface. PD caused instability during the completely voluntary nonslippery stops (P = 0.012) but not during the slippery stops, which required a reactive movement. The PD group walked slower [0.9–1.0 m/s vs. 1.3 m/s, respectively (P < 0.001)] with shorter steps during the first step of nonslippery GT (P = 0.016) and with wider steps during all steps of nonslippery GT (P ≤ 0.05). Similar to controls, the PD group increased lateral stability during planned GT compared to cued GT (P = 0.007). The timing of gait termination was similar between groups in all conditions. During the unexpected perturbation, both groups used a generalized slip response to regain balance after the perturbation. PD did not affect the ability to stop walking or to integrate a balance-correcting response into GT but did affect movement speed, size, and stability of the voluntary movement. © 2008 Movement Disorder Society
  Movement Disorders 10/2008; 23(14):1977 - 1983. · 4.51 Impact Factor
• Conference Proceeding: A VR-haptic locomotor system to retrain anticipatory postural adjustments post stroke

  A.R. Oates, C.F. Perez, J. Fung
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  ABSTRACT: The ability to use haptic input through light contact to improve stability while walking post-stroke is investigated in a virtual environment (VE). Persons with stroke and healthy participants walk in a VE where they encounter changes in the slope of the support surface. Kinematic, kinetic, and electromyographic data analyses will be used to show the anticipatory postural adjustments made leading up to and after a transition to a sloped surface. Pilot testing shows that the transition to sloped surface is more challenging for the stroke participant tested, as compared to an age-matched control. Modifications to the current protocol will improve the feasibility of not only task completion by both healthy and neurologically impaired participants, but also the ability to use and evaluate the use of haptic information for stability while walking in a VE with slope changes.
  Virtual Rehabilitation, 2008; 09/2008