Pilot study of a robotic protocol to treat shoulder subluxation in patients with chronic stroke

Abstract

Background: Shoulder subluxation is a frequent complication of motor impairment after stroke, leading to soft tissue damage, stretching of the joint capsule, rotator cuff injury, and in some cases pain, thus limiting use of the affected extremity beyond weakness. In this pilot study, we determined whether robotic treatment of chronic shoulder subluxation can lead to functional improvement and whether any improvement was robust.

Methods: 18 patients with chronic stroke (3.9 ± 2.9 years from acute stroke), completed 6 weeks of robotic training using the linear shoulder robot. Training was performed 3 times per week on alternate days. Each session consisted of 3 sets of 320 repetitions of the affected arm, and the robotic protocol alternated between training vertical arm movements, shoulder flexion and extension, in an anti-gravity plane, and training horizontal arm movements, scapular protraction and retraction, in a gravity eliminated plane.

Results: Training with the linear robot improved shoulder stability, motor power, and resulted in improved functional outcomes that were robust 3 months after training.

Conclusion: In this uncontrolled pilot study, the robotic protocol effectively treated shoulder subluxation in chronic stroke patients. Treatment of subluxation can lead to improved functional use of the affected arm, likely by increasing motor power in the trained muscles.

Figure 1

A. A patient working with the linear robot in the vertical plane (arrow locates the vertical sliding plane and the hand-machine contact). The patient is placed in a comfortable seated position, and compensatory torso movements are minimized by use of a seatbelt as well as constant supervision during the training by a skilled therapist. Visual feed-back is provided on a computer screen by a yellow ball that the patient has to move between targets. B. Demonstration of use of the robot in the horizontal, gravity eliminated plane (arrow locates the sliding plane and the point of hand-machine contact).