Stimulating rehabilitation: A new hybrid rehabilitation device combining robot and functional electrical stimulation for early stroke rehabilitation

The combination of robotic technology and Functional Electrical Stimulation (hybrid technology) utilizes the strength of each modality and counteracts the drawbacks. Currently, the knowledge about the effectiveness and clinical applicability of hybrid devices for the early rehabilitation of the lower extremity after stroke is limited. Therefore, the main aim of this thesis was to assess the feasibility, efficacy and clinical applicability of a new prototype of a robot rehabilitation device combined with functional electrical stimulation for the early rehabilitation of the lower extremities after a stroke. This dissertation consists of six studies. The first is a review, which investigated what hybrid devices are available for the lower extremity rehabilitation and the added value of electrical stimulation to robot therapy in stroke patients. ROBERT-SAS® is a new prototype combining robot support with FES for the lower extremity in early stroke rehabilitation. Ideally, the participants should actively-initiate FES, to increase its potential benefits. This actively-initiated FES can be based on voluntary muscle activity. To initiate FES, a threshold is needed as cut-off point to provide FES. The second study in this dissertation investigated four different threshold estimation methods based on muscle activity, to initiate FES, in stroke patients. Subsequently, a more sophisticated system was developed with an Assist-As-Needed approach to provide patients specific assistance and maximize the active involvement of the participant. The feasibility and efficacy of Assist-As-Needed robot combined with FES support were assessed among healthy volunteers (third study) and sub-acute stroke patients (fourth study), in a lab-based setting. The fifth study evaluated the relation between voluntary generated isometric force (six single joint movement) and functional ability, by means of sit-to-stand transfer and gait velocity. Furthermore, coupled forces (forces in other direction than the intended direction) where evaluated to assess the ability to perform selective movements and to assess the confounding factors of the measurement set-up. The last study of this dissertation evaluated the clinical applicability of ROBERT-SAS® training (three-six weeks intervention) in a clinical early rehabilitation setting for stroke patients. In general, this dissertation shows that it is feasible to execute a training of robot combined with FES in (sub) acute stroke patients. It is a promising tool to provide patient-specific active training, however the clinical applicability is dependent on environmental factors, like the workflow of specific rehabilitation centers.