Scientific Evidence


Robotic training with the ArmeoPower reduces motor impairment faster and more effectively than conventional therapy after stroke.1 This was shown in a multicenter trial by Verena Klamroth-Marganska and colleagues that was published recently in “The Lancet Neurology”.

To assess whether robotic training with the ARMin*, reduces motor impairment more effectively than conventional therapy, the team around Robert Riener from the Sensomotor Systems Lab of the ETH Zurich trained 77 chronic stroke patients with moderate to severe arm paresis in four clinical centers in Switzerland. Patients were randomly assigned into two groups, where they received either robotic or conventional therapy for at least 45min, three times per week for 8 weeks resulting in a total of 24 sessions. Assessment (Fugl Meyer Assessment of upper extremity, FMA-UE) was conducted 3 to 4 weeks before assignment, immediately before therapy, after 4 weeks,at the end of therapy and in week 16 and 34 as a follow up.

Robotic Therapy leads to Better Results than Conventional Therapy
After therapy, the changes in FMA-UE scores were significantly higher in patients assigned to robotic therapy than in those assigned to conventional therapy. About a third of these patients achieved FMA-UE gains of at least 5 points, known as the threshold for the minimum clinically important difference. Although most gains occurred in the first 4 weeks, patients still improved during the second half of the therapy without a plateau at the end of training. These results point at a possibility for further improvements if the training was continued.

Severely Impaired Patients Profit Most From Robotic Therapy
When patients were stratified by severity (<19 points versus >19 points in baseline FMA-UE), most severely affected patients seemed to profit the most from robot assisted therapy.

The authors conclude that task-oriented robotic training with the ARMin was safe and reduced motor impairment of the arm and hand more effectively than conventional therapy after stroke, particularly in chronic patients with moderate to severe impairment. Patients assigned to robotic therapy gained motor function faster than those assigned to conventional therapy. In the authors’ opinion the higher intensity of training with the ARMin might have been an important factor contributing to the differences, especially in patients with severe impairments.

Their findings are in accordance with a Cochrane meta-analysis2 published by Mehrholz et al. in 2012 comparing the efficacy of robotic devices with conventional therapeutic interventions for treatment of motor dysfunctions in upper limbs after stroke. The Cochrane meta-analysis also showed that arm function and activities of daily living improve with robotic devices. However, the devices used in those clinical studies mainly supported one joint or allowed for planar movements only. The study by Klamroth-Marganska is the first one investigating the efficacy of a multidimensional device like the ArmeoPower with advantages of robot assisted therapy over conventional approaches.

Please find a free abstract of the paper at

* Based on the ARMin technology developed at ETH Zurich and University Hospital Balgrist, the ArmeoPower allows a large range of motion in three dimensions and seven degrees of freedom. It supports the physiological movements of the shoulder and arm, as well as the opening and closing of the hand, and provides intensive and task-specific training strategies.

1. Mehrholz J, Hädrich A, Platz T, Kugler J, Pohl M. Electromechanical and robot-assisted arm training for improving generic activities of daily living, arm function, and arm muscle strength after stroke. Cochrane Database Syst Rev. 2012 Jun 13;6:CD006876.
2. Klamroth-Marganska V, Blanco J, Campen K, Curt A, Dietz V, Ettlin T, Felder M, Fellinghauer B, Guidali M, Kollmar A, Luft A, Nef T, Schuster-Amft C, Stahel W, Riener R. Three-dimensional, task-specific robot therapy of the arm after stroke: a multicentre, parallel-group randomised trial. Lancet Neurol. 2014 Feb;13(2):159-66.



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