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Robot-assisted arm assessments in spinal cord injured patients: a consideration of concept study.

Keller U, Schölch S, Albisser U, Rudhe C, Curt A, Riener R, Klamroth-Marganska V - PLoS ONE (2015)

Bottom Line: We investigated whether a set of robot-based assessments that encompasses kinematic, kinetic and timing metrics is applicable, safe, reliable and comparable to clinical metrics for measurement of arm motor function.In conclusion, the therapy robot ARMin provides a comprehensive set of assessments that are applicable and safe.The methods applied and results can serve as a basis for the future development of end-effector and exoskeleton-based robotic assessments.

View Article: PubMed Central - PubMed

Affiliation: Sensory-Motor Systems Lab, Department of Health Sciences and Technology ETH Zurich, Zurich, Switzerland; Balgrist University Hospital, University of Zurich, Zurich, Switzerland.

ABSTRACT
Robotic assistance is increasingly used in neurological rehabilitation for enhanced training. Furthermore, therapy robots have the potential for accurate assessment of motor function in order to diagnose the patient status, to measure therapy progress or to feedback the movement performance to the patient and therapist in real time. We investigated whether a set of robot-based assessments that encompasses kinematic, kinetic and timing metrics is applicable, safe, reliable and comparable to clinical metrics for measurement of arm motor function. Twenty-four healthy subjects and five patients after spinal cord injury underwent robot-based assessments using the exoskeleton robot ARMin. Five different tasks were performed with aid of a visual display. Ten kinematic, kinetic and timing assessment parameters were extracted on joint- and end-effector level (active and passive range of motion, cubic reaching volume, movement time, distance-path ratio, precision, smoothness, reaction time, joint torques and joint stiffness). For cubic volume, joint torques and the range of motion for most joints, good inter- and intra-rater reliability were found whereas precision, movement time, distance-path ratio and smoothness showed weak to moderate reliability. A comparison with clinical scores revealed good correlations between robot-based joint torques and the Manual Muscle Test. Reaction time and distance-path ratio showed good correlation with the "Graded and Redefined Assessment of Strength, Sensibility and Prehension" (GRASSP) and the Van Lieshout Test (VLT) for movements towards a predefined position in the center of the frontal plane. In conclusion, the therapy robot ARMin provides a comprehensive set of assessments that are applicable and safe. The first results with spinal cord injured patients and healthy subjects suggest that the measurements are widely reliable and comparable to clinical scales for arm motor function. The methods applied and results can serve as a basis for the future development of end-effector and exoskeleton-based robotic assessments.

No MeSH data available.


Related in: MedlinePlus

Visual representation of the WORKSPACE assessment package.Screenshot of the WORKSPACE assessment. A room was presented on the screen. The patient looked directly into this room. The end effector of the robot (the position of the patient’s hand) was represented as a small red cube. In the shown situation the patient had to move to the green target position to the right.
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pone.0126948.g002: Visual representation of the WORKSPACE assessment package.Screenshot of the WORKSPACE assessment. A room was presented on the screen. The patient looked directly into this room. The end effector of the robot (the position of the patient’s hand) was represented as a small red cube. In the shown situation the patient had to move to the green target position to the right.

Mentions: WORKSPACE assessment aimed to measure the reachable cubic workspace of the end effector (i.e., the hand). The starting position of the hand was 30 cm in front of the breast (i.e., the xiphoid process of sternum). On the screen, a small cubic room (corresponding to an initial size of 20 cm x 20 cm x 20 cm in the real world) was presented (Fig 2). Each wall in the room indicated a direction to move to (top, bottom, left, right, towards the body, away from the body). For simplification, more directions such as diagonals were not assessed. The aimed movement direction was indicated by a green cube on the wall in randomized order. After the patient had reached the indicated wall, the room grew 5 cm in this direction. If the subject missed an indicated wall the room did not grow in this direction and the direction was shown once more later. The number of discrete increases in a certain direction refers to as a level and was used as an outcome parameter (workspace level, in numbers). Furthermore, the achieved room size (cubic volume, in dm3) was calculated from the workspace levels reached. The maximal volume of the room was 140 dm3, the initial size was 8 dm3 and the maximal distances to the given room walls were 35 cm for the left and right (five movements in each direction to reach maximum expansion), 30 cm for the top (four movements to reach maximum expansion), and 20 cm for the bottom direction, towards the body and away from the body (two movements in each direction to reach maximum expansion). This results in a total of 20 movements to discretely increase the room size to its maximum.


Robot-assisted arm assessments in spinal cord injured patients: a consideration of concept study.

Keller U, Schölch S, Albisser U, Rudhe C, Curt A, Riener R, Klamroth-Marganska V - PLoS ONE (2015)

Visual representation of the WORKSPACE assessment package.Screenshot of the WORKSPACE assessment. A room was presented on the screen. The patient looked directly into this room. The end effector of the robot (the position of the patient’s hand) was represented as a small red cube. In the shown situation the patient had to move to the green target position to the right.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4440615&req=5

pone.0126948.g002: Visual representation of the WORKSPACE assessment package.Screenshot of the WORKSPACE assessment. A room was presented on the screen. The patient looked directly into this room. The end effector of the robot (the position of the patient’s hand) was represented as a small red cube. In the shown situation the patient had to move to the green target position to the right.
Mentions: WORKSPACE assessment aimed to measure the reachable cubic workspace of the end effector (i.e., the hand). The starting position of the hand was 30 cm in front of the breast (i.e., the xiphoid process of sternum). On the screen, a small cubic room (corresponding to an initial size of 20 cm x 20 cm x 20 cm in the real world) was presented (Fig 2). Each wall in the room indicated a direction to move to (top, bottom, left, right, towards the body, away from the body). For simplification, more directions such as diagonals were not assessed. The aimed movement direction was indicated by a green cube on the wall in randomized order. After the patient had reached the indicated wall, the room grew 5 cm in this direction. If the subject missed an indicated wall the room did not grow in this direction and the direction was shown once more later. The number of discrete increases in a certain direction refers to as a level and was used as an outcome parameter (workspace level, in numbers). Furthermore, the achieved room size (cubic volume, in dm3) was calculated from the workspace levels reached. The maximal volume of the room was 140 dm3, the initial size was 8 dm3 and the maximal distances to the given room walls were 35 cm for the left and right (five movements in each direction to reach maximum expansion), 30 cm for the top (four movements to reach maximum expansion), and 20 cm for the bottom direction, towards the body and away from the body (two movements in each direction to reach maximum expansion). This results in a total of 20 movements to discretely increase the room size to its maximum.

Bottom Line: We investigated whether a set of robot-based assessments that encompasses kinematic, kinetic and timing metrics is applicable, safe, reliable and comparable to clinical metrics for measurement of arm motor function.In conclusion, the therapy robot ARMin provides a comprehensive set of assessments that are applicable and safe.The methods applied and results can serve as a basis for the future development of end-effector and exoskeleton-based robotic assessments.

View Article: PubMed Central - PubMed

Affiliation: Sensory-Motor Systems Lab, Department of Health Sciences and Technology ETH Zurich, Zurich, Switzerland; Balgrist University Hospital, University of Zurich, Zurich, Switzerland.

ABSTRACT
Robotic assistance is increasingly used in neurological rehabilitation for enhanced training. Furthermore, therapy robots have the potential for accurate assessment of motor function in order to diagnose the patient status, to measure therapy progress or to feedback the movement performance to the patient and therapist in real time. We investigated whether a set of robot-based assessments that encompasses kinematic, kinetic and timing metrics is applicable, safe, reliable and comparable to clinical metrics for measurement of arm motor function. Twenty-four healthy subjects and five patients after spinal cord injury underwent robot-based assessments using the exoskeleton robot ARMin. Five different tasks were performed with aid of a visual display. Ten kinematic, kinetic and timing assessment parameters were extracted on joint- and end-effector level (active and passive range of motion, cubic reaching volume, movement time, distance-path ratio, precision, smoothness, reaction time, joint torques and joint stiffness). For cubic volume, joint torques and the range of motion for most joints, good inter- and intra-rater reliability were found whereas precision, movement time, distance-path ratio and smoothness showed weak to moderate reliability. A comparison with clinical scores revealed good correlations between robot-based joint torques and the Manual Muscle Test. Reaction time and distance-path ratio showed good correlation with the "Graded and Redefined Assessment of Strength, Sensibility and Prehension" (GRASSP) and the Van Lieshout Test (VLT) for movements towards a predefined position in the center of the frontal plane. In conclusion, the therapy robot ARMin provides a comprehensive set of assessments that are applicable and safe. The first results with spinal cord injured patients and healthy subjects suggest that the measurements are widely reliable and comparable to clinical scales for arm motor function. The methods applied and results can serve as a basis for the future development of end-effector and exoskeleton-based robotic assessments.

No MeSH data available.


Related in: MedlinePlus