Enriched Environments for Stroke Rehabilitation; Pilot Study to Determine Appropriate Outcome Measures and Their Sensitivity to Different Training Protocols

A. Scientific Background

Stroke is the third leading cause of death in Western countries and upper limb (UL) sensorimotor dysfunction contributes significantly to the incidence of physical disabilities and handicaps (Olsen 1990). One explanation for poor arm recovery is the focus on task accomplishment rather than performance quality. This may reinforce alterative (compensatory) movement strategies instead of encouraging the reappearance of pre-morbid movement patterns (recovery). Although the rehabilitative goal is recovery of function, whether this is achieved through true motor recovery or compensation is still under debate. Indeed, for some patients with severe impairment, compensation should be encouraged to maximize functional ability. Alternatively, for those with good prognosis, motor recovery is emphasized for several reasons. First, given appropriate training, recovery can continue well into the chronic stage of stroke (e.g., Michaelsen & Levin 2004). Second, while compensation may assist immediate performance, it may lead to longer-term problems such as pain and contracture (Ada et al. 1994; Levin 1997). Third, permitting compensations could encourage learned nonuse limiting the capacity for subsequent motor gains (Allred et al. 2005). While performance gains have been documented after repetitive training of isolated movements (e.g., Whitall et al. 2000), few studies have addressed whether patients can use explicit information to optimize motor skill acquisition and whether true behavioural recovery occurs. Points to consider in developing optimal training programs is that learning occurs when participants are motivated, practice a variety of related tasks and are given relevant feedback (Nudo & Friel 1999; Winstein et al. 1999). In addition, patients may not benefit from variable practice until missing motor elements are recovered (Carr & Shepherd 1987) and motor relearning is related to physical and cognitive impairment level (Cirstea et al. 2006).

To date, most studies have used only clinical measures to evaluate functional change (e.g., Jang et al. 2003) without considering how movement is performed. This study will focus on the ability to distinguish between whether functional improvement results from an increase in compensation or from true motor recovery. This can only be done by correlating functional improvement (clinical measures) with changes in arm motor patterns through detailed movement analysis (kinematics). Since there are a large number of possible kinematic indicators of improvement, the investigators need to identify which measures are most indicative of change. This is a first step in the determination of clinically meaningful outcome measures to be used in randomized control trials of the effectiveness of interventions. Clinical salience is essential to translate knowledge from research studies to evidence-based practice (van Peppen et al. 2007).

B. Study Design: 1. Detailed Plan of the Study

Two groups of 8 stroke subjects will participate in an A-B-A design in which data from post-intervention (within one week of the completion of the intervention) and follow-up (one month after the completion of the intervention)tests will be compared to data from two pre-tests (held at beginning and end of the first week of the study just prior to the start of the intervention). Multiple clinical and kinematic motor performance outcomes will be measured to determine which ones best describe arm motor recovery. This will be done by comparing changes in outcomes before and after training to mean scores of 8 age- and gender-matched healthy volunteers (recorded in a single session). Stroke survivors will practice movement in two different training environments providing different levels of motivation and feedback: Training Environment 1 will be created in a 2D video-based VR environment that will provide high motivation, Knowledge of Results (KR) about motor outcome (i.e., speed, precision) and non-specific Knowledge of Performance (KP) feedback about trunk movement. Environment 2 will be created in a physical environment that provides only KP feedback but no KR or additional motivation.