Restitution and compensation in the recovery of function in the lower extremities of stroke survivors : design of evaluation and training methods

Abstract

Since restoration of motor function in walking and stance is an important aspect in the rehabilitation of stroke patients, insight in the responsible recovery mechanisms is of great importance. Generally, two recovery mechanisms are distinguished: restitution and compensation. In restitution, the increase in motor function is attributed to a return of original movements and or function of the paretic leg, whereas in compensation the increase in motor function is ascribed to the emergence of new movement strategies or to secondary adaptations in the non paretic leg to compensate for the decreased motor abilities in the paretic leg. To assess the contribution of the different mechanisms in the recovery of motor function, we need to develop appropriate methods to quantify restitution and compensation in time. Besides, the contributions of the separate recovery mechanisms can also be derived from the effectiveness of therapeutic interventions that focus specifically on using original movement patterns (restitution) or alternative movement strategies (compensation). Robotic rehabilitation devices can well be used in emphasizing the use of certain movement strategies during training, as they can support the movements of the subject during practicing. However, practicing compensatory\ud strategies in the device is only possible if the mechanical design of the device allows for it and if the control of the device provides the flexibility to the subjects in choosing their movement strategy. The latter requires the implementation of “assist-as-needed” algorithms that only provide assistance to the subject when it is needed to successfully fulfill the task