Ambulation recovery after stroke

Abstract

Most stroke survivors regard successful independent ambulation important. However, ambulation recovery is limited following stroke. Historically, limited availability of objective tools and measures to characterise free-living ambulation recovery has restricted investigation of this outcome after survivors return home. However, commercially available devices, including accelerometers and portable global positioning systems, are now available. Thus, this thesis aimed to characterise free-living ambulation recovery over the first six months after stroke survivors returned home from hospital and determine what factors at discharge contributed to ambulation recovery across this time. The first study of this thesis investigated the concurrent validity and retest reliability of accelerometers (ActivPAL and Sensewear Pro2 Armband) and global positioning systems (GPS) (Garmin forerunner 405CX) to measure free-living ambulation after stroke. Measures of step counts, time spent walking, energy expenditure, distance and location were taken during walking tasks that impose demands similar to those encountered when walking in the community as well as free-living community ambulation over four days. This study determined that the ActivPAL was valid and reliable for measuring ambulation after stroke. The GPS was valid and reliable for all measures except distance, whereas the Sensewear Pro2 Armband recorded with high error during all walking tests. The second study aimed to characterise ambulation activity after stroke across the first six months following discharge from hospital and investigate how ambulation activity changed across this time period. Free-living ambulation activity was measured over four days using the ActivPAL accelerometer at one, three and six months after stroke survivors left hospital. Measures of volume (daily step counts and time spent walking, sitting/lying, standing and upright), frequency (total number of ambulation bouts; number of bouts and total time spent in short, medium and long duration ambulation bouts) and intensity (number of bouts and total time per day spent in low, moderate and high intensity ambulation bouts) of ambulation activity were collected. This study highlighted that volume of ambulation activity was low across the first six months following hospital discharge, with a majority of ambulation bouts short and low in intensity. Stroke survivors rarely engaged in long duration and high intensity ambulation bouts across the first six months. Daily volume of ambulation activity increased from one month to both three and six months after discharge from hospital through an increase in medium duration and moderate intensity ambulation only. The third study aimed to determine what factors at discharge were related to and predicted ambulation activity outcomes over the first six months following hospital discharge in stroke. Factors including age, fatigue, mood, executive function, gait speed, gait endurance, perceived stroke recovery, pre-stroke physical activity, ambulatory self- efficacy and perceived health outcome and status were assessed for their ability to predict volume, frequency and intensity of ambulation activity at one, three and six months after hospital discharge. Gait endurance predicted all outcomes of ambulation activity at one month, and intensity of ambulation at three and six months after discharge from hospital. Beyond one month, pre-stroke activity, age and executive function also contributed to ambulation activity outcomes. The fourth study explored characteristics of community ambulation across one, three and six months after stroke survivors were discharged from hospital and determined if community ambulation changed over time. Stroke survivors regularly accessed their community, spending most time each day in long duration and moderate intensity ambulation bouts, except at three months, where most time was spent in medium duration bouts. No changes in community ambulation were observed until six months, when stroke survivors spent more time in long duration ambulation bouts. The final study aimed to determine what factors at discharge predicted community ambulation outcomes at one, three and six months following hospital discharge. Discharge gait endurance best predicted community ambulation at one month after hospital-discharge. However, similar to ambulation activity, beyond one month, age, pre-stroke activity and executive function predicted outcomes. Volume of community ambulation could not be predicted by any factor at discharge after one month. This thesis concludes that, ambulation activity after stroke is low following discharge from hospital. Improvements in activity are generally realised through increased time spent in medium duration and moderate intensity ambulation bouts, with no change in long duration or high intensity activity over time. Recovery of community ambulation is not observed until months after discharge home. Discharge gait endurance best predicts all ambulation outcomes at one month after hospital discharge. After one month, age, pre-stroke activity and executive function contribute to free-living ambulation outcomes. Increasing gait endurance should be a goal during rehabilitation after stroke. Further, characteristics of stroke survivors who are younger, active prior to stroke and able to initiate and manage multiple tasks should be harnessed during management of free-living ambulation recovery. Further investigation of other factors is required, as not all outcomes were explained by the factors measured in this thesis.