Motor Task Performance Under Visual and Auditory Feedback Post Stroke: a Randomized Crossover Trial

The study was designed to evaluate the impact of a novel kinematic biofeedback system - SWORD - in the motor performance of patients after stroke. The SWORD system combines inertial motion trackers and a mobile app, allowing digitization of patient motion and providing real-time audiovisual biofeedback. The investigators hypothesize that the biofeedback feedback provided by the SWORD system improves patient performance, defined as an increase in the number of correct movements. The design of the study is a cross-over randomized clinical trial. Patients will be randomized into two groups. Both will perform two separate sessions consisting of one exercise - shoulder flexion with elbow flexion at 90 degrees - for 4 minutes in both experimental settings: with and without biofeedback. Group 1 will perform the exercise with biofeedback first and without biofeedback after, with an interval >24h. Group 2 will perform the exercise in the opposite order. The SWORD system will be used to record movement data in both sessions, but the feedback was only active in one of them.

The patient will perform one repetition of the exercise shoulder flexion with elbow flexion at 90 degrees under monitoring from SWORD. The recorded parameters will be used to define: baseline and target angle; execution time; maximum postural sway. Two additional repetitions will be performed to ensure reproducibility. During the session, SWORD will be providing real-time audiovisual feedback. The patient has to start in the baseline position and fill the progress bar without violating movement or posture constraints. If the patient does not reach the goal or violates constraints he will receive a negative audio feedback, the progress bar will turn red and be reset. The patient has to return to the baseline position to restart the movement.

The patient will perform one repetition of the exercise shoulder flexion with elbow flexion at 90 degrees under monitoring from SWORD. The recorded parameters will be used to define: baseline and target angle; execution time; maximum postural sway. Two additional repetitions will be performed to ensure reproducibility. The patient will then be instructed to perform as many movements as possible during the allocated time (4 minutes), at a comfortable pace, starting at or below the baseline and trying to reach maximum flexion without significant pain or discomfort. During the session, the SWORD system will be recording the patient´s movement without providing feedback to the patient.

Both arms will perform two separate sessions consisting of one exercise - shoulder flexion with elbow flexion at 90 degrees - for 4 minutes in two experimental conditions: with and without biofeedback. Group 1 will perform the exercise with biofeedback first and without biofeedback after; group 2 performed the exercise in the opposite order. The SWORD system will be used to record movement data in both sessions.

Between the second and first minute; between the second and third minutes; between the third and fourth minute

Inclusion Criteria: clinical symptoms and signs and CT or MRI findings compatible with a lesion in the territory of the medial cerebral artery; persistent motor deficit on the upper limb but not plegia with a score between 0 and 2 on item 5b of the National Institute of Health Stroke Scale (NIHSS) more than 2 weeks after stroke onset; the ability to sit comfortably for more than 10 minutes and perform two-step commands Exclusion Criteria: no detectable motor deficits at baseline assessment; severe aphasia; clinical dementia or mini mental state examination (MMSE) below cutoff; other cognitive or psychiatric comorbidity that impaired communication or compliance with the tasks; severe respiratory or cardiac condition incompatible with more than 5 minutes of continuous mild exercise in a sitting position; pain or deformity that limited upper limb movement on the affected side.