Maximising Upper Limb Recovery after Stroke

Upper limb recovery after stroke is unacceptably poor. As few as one in five stroke survivors regain functional use of the arm, compared with four out of five who regain the ability to walk again. With more people surviving strokes, and with an increase in severe disability, greater demand on services has led to a reduction in hospital length of stay. As the time available for upper limb training is rapidly diminishing, the search for effective and efficient strategies to promote upper limb recovery has become more pressing. Consequently, the aim of this project was to investigate how to maximise upper limb recovery across the stroke population. The first objective was to identify factors that influence recovery, from the stroke survivors perspective and the scientific literature. The second objective was to develop and evaluate a training program to promote upper limb recovery. A mixed methodology design, which included qualitative and quantitative approaches, was utilized. The project began with a series of focus groups and in-depth interviews with stroke survivors from rural and metropolitan areas of Queensland, Australia (n = 29). A long term view of recovery, with stroke recovery services supporting stroke survivors to drive their own recovery, was advocated. Based on these findings, a quantitative mail-out survey was developed and administered to stroke survivors throughout Queensland (n = 220). The single most important factor found to contribute to recovery was the use of the arm in everyday tasks. The second most important factor, which represented the greatest barrier to upper limb recovery, was not enough movement to work with. With these findings in mind, review of the scientific literature was undertaken. Motor impairment and the loss of normal movement synergies were identified as key causes of upper limb disability. To enhance recovery across the population, interventions which increase muscle strength and flexibility, and promote reacquisition of skill were recommended. Review of the clinical evidence provided support for this recommendation in part, with intensive and repetitive task-oriented practice found to be effective in promoting upper limb recovery. However, in the context of severe paresis, the application or effectiveness of this approach had not been clearly demonstrated. Therefore, the challenge of this thesis was to make task-oriented practice possible for stroke survivors with severe paresis. Combining the perspective of stroke survivors with the scientific literature, a new intervention was developed to train the task of reaching in stroke survivors with severe paresis. This intervention included a custom built training device, the SMART Arm, for use with or without Electromyography-Triggered Functional Electrical Stimulation (ETS) to the triceps brachii muscle to augment elbow extension. The final stage of the project involved a randomised controlled trial (RCT) to assess the efficacy of this newly developed intervention in stroke survivors with severe and chronic upper limb paresis. Of the 33 participants who completed the study, 10 received training in reaching to a target using the SMART Arm with ETS, 13 received the same training but without ETS and 10 received no intervention. Significant improvements in arm impairment and activity limitations occurred after only 12 hours of training, and were maintained two months after training had ceased. No significant changes occurred for those who did not receive training. Changes in triceps and biceps electromyography (EMG) activity indicated that increased coordination of muscles involved in the reaching task may have contributed to improvements. Changes measured using transcranial magnetic stimulation (TMS) demonstrated that contralateral corticospinal excitability had improved after training in parallel with changes in arm function. While it was apparent that this was the most efficient mechanism for recovery, variation in the utilisation of contralateral and ipsilateral pathways indicated that a number of different mechanisms may have been responsible for recovery of upper limb function. Contrary to our hypothesis, training with, compared to without ETS, did not lead to greater improvements in arm function. Difficulties associated with use of EMG activity to trigger delivery of electrical stimulation (ES) may have concealed possible benefits. Hence, our future research will investigate movement outcome as an alternative method for triggering ES. The study findings confirm that intensive and repetitive task-oriented practice promotes upper limb recovery, even in stroke survivors with severe and chronic paresis. This represents a critical step towards enabling a greater proportion of stroke survivors to drive their own recovery, thereby increasing the potential for improved upper limb recovery across the population