Consistent rising-to-walk parameters in health as candidates to assess rehabilitative change in transitional walking after stroke

Abstract

Optimal physiotherapeutic strategies to rehabilitate walking post-stroke and biomechanical parameters that differentiate health from impairment during the complex transitional movement of rising-to-walk (RTW) remain to be defined. However, parameters that remain consistent within the extremes of healthy RTW performance, defined as sit-to-walk (STW) and sit-to-stand-and-walk (STSW), represent candidates that might discriminate normal from impaired movement control and evaluate change in RTW performance during stroke rehabilitation. This is because normal movement control remains a feature of healthy RTW irrespective of how it is performed. So, consistent parameters are candidates with which to discriminate impairment and assess rehabilitative change in transitional walking after stroke by virtue of their consistency in health. Initially a systematic literature review assessed if consistent biomechanical parameters across the extremes of RTW performance have been reported. It revealed 5 full-text studies in which any two RTW sub-tasks (STW, sit-to-stand (STS), or gait-initiation (GI)) in healthy participants were biomechanically assessed. No evidence of an explicit aim to determine consistent parameters was revealed in the studies, they lacked a common protocol, their sample sizes were small, and most parameters abstracted were unique to only one study. Meta-analyses could only conclude potential evidence of consistent parameters. Therefore, a novel RTW protocol designed to be safe for stroke survivors (rising from "2I% knee-height upon a visual cue, walking purposefully ahead [m and stopping, non-dominant leg-lead) was developed from which three parameters (flexionmomentum time, peak rising vertical-momentum, and peak 3rd step postural-stability) were found to be consistent across "I healthy individuals performing STW and STSW, where a pause separates STS from GI. To determine representative RTW transition phase-times (seat-off to GI-onset) in health and pathology, the protocol was replicated in 2" ambulatory stroke survivors and in 2I aged-matched healthy adults. Two parameters (flexion-momentum time, and peak 3rd step postural-stability) remained consistent during STW and STSW. Peak lateral groundreaction- force (towards the stance-limb) was found to be a valid and reliable GI-onset estimate method irrespective of RTW performance, with representative transition phasetimes found to range between I and J.Is. Then, a third experiment was performed in another "4 ambulatory stroke survivors and "5 age-matched healthy adults where transition phase-times were manipulated randomly between I, ".[[, 3.[4, and J.I2s after seat-off using an audible signal. Flexion-momentum time, and peak 3rd step postural-stability remained consistent independent of transition phase-time in health, but were able to discriminate pathology. Therefore, flexionmomentum time and peak 3rd step postural-stability appear to be strong candidates to discriminate RTW performance between health and pathology, and to potentially evaluate change in response to rehabilitation treatments for pathological RTW performance after stroke.

Date of Award	1 Jun 2020
Original language	English
Awarding Institution	King's College London
Supervisor	David Green (Supervisor) & Michael Thacker (Supervisor)