Evaluation of upper extremity robot-assistances in subacute and chronic stroke subjects.
BACKGROUND
Robotic systems are becoming increasingly common in upper extremity stroke rehabilitation. Recent studies have already shown that the use of rehabilitation robots can improve recovery. This paper evaluates the effect of different modes of robot-assistances in a complex virtual environment on the subjects' ability to complete the task as well as on various haptic parameters arising from the human-robot interaction.


METHODS
The MIMICS multimodal system that includes the haptic robot HapticMaster and a dynamic virtual environment is used. The goal of the task is to catch a ball that rolls down a sloped table and place it in a basket above the table. Our study examines the influence of catching assistance, pick-and-place movement assistance and grasping assistance on the catching efficiency, placing efficiency and on movement-dependent parameters: mean reaching forces, deviation error, mechanical work and correlation between the grasping force and the load force.


RESULTS
The results with groups of subjects (23 subacute hemiparetic subjects, 10 chronic hemiparetic subjects and 23 control subjects) showed that the assistance raises the catching efficiency and pick-and-place efficiency. The pick-and-place movement assistance greatly limits the movements of the subject and results in decreased work toward the basket. The correlation between the load force and the grasping force exists in a certain phase of the movement. The results also showed that the stroke subjects without assistance and the control subjects performed similarly.


CONCLUSIONS
The robot-assistances used in the study were found to be a possible way to raise the catching efficiency and efficiency of the pick-and-place movements in subacute and chronic subjects. The observed movement parameters showed that robot-assistances we used for our virtual task should be improved to maximize physical activity.
Laboratory of Robotics, Faculty of Electrical Engineering, University of Ljubljana, Trzaska c, 25, 1001 Ljubljana, Slovenia. jaka.ziherl@robo.fe.uni-lj.si
Jaka
J
Ziherl
Domen
D
Novak
Andrej
A
Olenšek
Matjaž
M
Mihelj
Marko
M
Munih
D000328:Adult; D000368:Aged; D002908:Chronic Disease; D003627:Data Interpretation, Statistical; D005260:Female; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010291:Paresis / Q000534:rehabilitation; D011597:Psychomotor Performance / Q000502:physiology; D012371:Robotics; D012656:Self-Help Devices; D000071939:Stroke Rehabilitation; D013647:Task Performance and Analysis; D034941:Upper Extremity / Q000502:physiology*; D014937:Work; D055815:Young Adult