Trunk Restraint Therapy: the Continuous Use of the Harness Could Promote Feedback Dependence in Post-stroke Patients. A Randomized Trial.

Twenty stroke subjects were recruited from the Physiotherapy and Occupational Therapy Outpatient Unit of the University Hospital at Campinas - UNICAMP and all of them signed informed consent forms previously approved by the Research Ethics Committee of the University (#110/2004). Ten healthy subjects were also selected to obtain normal reference parameters of kinematic assessment. Patients had sustained a single and chronic (>6 months post-event) unilateral stroke of non-traumatic origin, with hemiparetic sequel in the upper limb, could understand simple instructions, perform community gait, and had a good sitting balance. Those with shoulder pain or other neurological and orthopedic conditions affecting the reaching movement ability or trunk, hemispatial neglect or apraxia were excluded. The patients who met the inclusion criteria were stratified to one of two groups. A sealed opaque envelope containing a single cheat of paper marked with numbers 1 (group 1) or 2 (group 2), was used to allocate the patient. This procedure was made by an external assessor. The patients were not informed about the different treatment groups and therefore, they were blind for the type of intervention applied.

The muscle tone (shoulder and elbow flexors) was evaluated using the Modified Ashworth Scale (MAS)9; motor impairment was evaluated using the upper limb section of Fugl-Meyer Assessment Scale (FM) and activities of daily living was assessed by the Barthel Index (BI). Kinematic data were recorded by an infrared system of motion analysis (Qualisys Motion Capture System - 2.57 Sweden) with sample frequency of 240 Hz, during 8 seconds. The coordinated data was low-pass filtered using a 6 Hz, finite impulse response filter with order 26 using the Matlab software. Five infrared reflexive markers were used. For the kinematic capture, the subjects were seated in a chair and invited to fit a cone in a target placed within arm's length (measured on the non-affected arm from the medial border of axilla to the distal wrist crease). The target was placed so that only the arm movement was required to reach the target. The initial hand position of the affected arm was on the lateral trunk, with the shoulder in neutral position and the elbow close to the side of the body (90°). Three trials of 6 to 8 seconds' time were recorded and a media was used to calculate the evaluated data.From the collected dates, values concerning to sagittal (YZ), horizontal (XY) and 3-dimensional (XYZ) planes were computed.

Trunk displacement was verified in millimeters as sagittal movement of marker 3.

Index of curvature was measured from marker 5. This index shows the straightness of the wrist trajectory from the initial position to the goal, resulting in a ratio of actual end point path to a straight line (index = 1, whereas a semicircle has an index of 1.57).

Shoulder angles were calculated using 2 vectors formed from marker 1 to marker 2, and from marker 2 to marker 4; with flexion/extension movements in sagittal plane and adduction/abduction movement in horizontal plane. Full horizontal abduction and the anatomical position were considered at 0°. Flexion/extension elbow angles were measured using 2 vectors formed from marker 2 to 4 and from marker 4 to 5, using the sagittal and horizontal planes. The elbow full extension was considered at 180°.