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20.18 Inverse-dynamics based assessment of walking using a robotic gait orthosis
Chapter 20. Rehabilitation and training I2~
Use of real-time bandwidth kinematic feedback in learning a cyclical lower limb movement skill
M. Hanlon, R. Anderson. Biomechanics Research Unit, University
of Limerick, Ireland
of young healthy subjects. These results also stress usefulness of coordinated head movements during balance exercises at unstable surface.
•
Introduction: Simple bandwidth feedback (SBF) tells when per-
formance is within or outside prescribed limits [1]. This study investigates the use of real-time SBF of knee angle in learning a novel cyclical lower limb movement skill. Methods: Sixteen healthy adult volunteers gave informed consent to participate in the study for 4 weeks (2 sessions/week). Each session consisted of 50 SBF training trials where subjects attempted to learn and accurately replicate a 4-second movement of the fight leg in the sagittal plane followed by 5 non-feedback retention trials. An instrumented knee brace provided real-time values for the subject's knee angle (at 50 Hz). This allowed comparison of the subject's movement to the ideal values. During the 4-second movement, SBF was given via two indicators, one triggered at every instant the subject's knee angle was above the prescribed limit, another at every instant the subject's knee angle was below the prescribed limit. Results: Early results (n 6) show a 49±32% reduction in error during feedback trials from session 1 to 6 and a 26±21% reduction in error during non-feedback trials from session 1 to 6. Full results will follow as training is still in progress. Discussion: Steady performance improvements can be made when learning a novel skill with relatively simple feedback which just indicates when the movement is outside prescribed bands, but not the amplitude of the error. Further training may be required to learn to accurately carry out skill when feedback is removed. Gait rehabilitation could benefit from similar techniques. Funding for this research is provided by the Irish Research Council for Science, Engineering and Technology: funded by the National Development Plan.
References [1] Schiffman JM, Luchies CW, Richards LG, Zebas CJ. The effects of age and feedback on isometric knee extensor force control abilities. Clin Biomech 2002; 17:486 493.
$131
Inverse-dynamics based assessment of walking using a robotic gait orthosis
J.M. Hidler 1'2, S. Goldberg 1'3. 1Center for Applied Biomechanics
and Rehabilitation Research, National Rehabilitation Hospital, Washington, DC, USA; 2Department of Biomedical Engineering, Catholic University, Washington, DC, USA; 3PhysicalDisabilities Branch, National Institutes of Health, Bethesda, MD, USA Introduction: The goal of this work is to develop a quantitative method for evaluating walking performance in individuals with significant gait impairments during robotic-assisted gait training. The ability to monitor walking performance under various training conditions will, for the first time, provide therapists the information necessary to establish the optimal training parameters for maximizing patient recovery. Methods: The device used in this study is a Lokomat ® roboticgait orthosis [1], which actively assists leg movements during bodyweight supported treadmill training. The leg curls that couple the subject to the Lokomat have been modified with six-axis force sensors to record interaction forces, while an ADAL3D treadmill is used to record ground reaction forces and centers of pressure. Using these kinetic data along with measured joint kinematics, a real-time inverse dynamics technique [2] has been developed to quantify ankle, knee, and hip moments exerted by the subject while ambulating on the treadmill within the Lokomat. Results: The proposed technique is now being tested using healthy individuals with no gait disorders, where we are evaluating the sensitivity of the predicted joint moments on important anatomical measures, including leg centers of mass, inertial components, and joint w~es of rotation. Conclusions: Using this technique, we will study the influence of key gait training parameters such as walking speed and level of body-weight support on stepping ability in individuals following neurological injury.
References I2~
The effects of four weeks aerotrim ® training period on postural balance
H. Hannola 1, H. Pekkarinen 2. 1Rovaniemi Polytechnic, School of Sports' and Leisure, Rovaniemi, Finland," 2University of Kuopio, Faculty of Medicine, Kuopio, Finland Introduction: Sufficient ability to maintain static and dynamic balance is necessary both in world-class sports and normal daily living. The purpose of this study was to examine the effects of four weeks Aerotfim ® training period on postural balance. Methods: Twenty-six sport instructor students participated in this study. Students were divided into two groups, test group (n 13) and control group (n 13). Postural stability was assessed using Head Shake Sensory Organization Test (HS-SOT) on the NeuroCom SmartEquitest. Test group was training for four weeks, three times ® a week, with Aerotfim training equipment. After this intervention postural stability was assessed again. The differences between assessments were statistically calculated using a paired samples t-test design. Results: The results of the study indicate that head motions at unstable surface significantly decrease equilibrium scores of normal subjects. They also indicate that four weeks Aerotfim ® training period significantly improves the HS-SOT equilibrium scores under altered support surface conditions. Discussion and Conclusions: Preliminary published results indicate that the HS-SOT does significantly expand the sensitivity and utility of the standard Sensory Organization Test (SOT). This study also indicated that especially HS-SOT under altered support surface conditions is sensitive enough to differentiate balance abilities
[1] Colombo G, Joerg M, Schreier R, Dietz V. Treadmill training of paraplegic patients using a robotic orthosis. Journal of Rehabilitation Research and Development 2000; 37:693 700. [2] Winter D, Biomechanics and motor control of human movement, John Wiley & Sons, 1990.
•
Audio biofeedback: sensory substitution for vestibular loss
EB. Horak 1, M. Dozza 1'2, L. Chiafi 2. 1Neurological Sciences' Institute, Oregon Health & Science University, Beaverton, OR, USA; 2Dept. of Electronics Computer Science and Systems, University of Bologna, Bologna, Italy Introduction: This study tests the hypothesis that audio-biofeedback
(ABF) signaling accelerations related to body center of mass movements can provide an effective and specific sensory substitution for loss of vestibular information. Methods: We quantified the effects of ABF on standing postural sway (center of foot pressure area) of 9 subjects with profound, bilateral loss of vestibular function (BVL) and 9 age-matched, healthy control subjects under 3 conditions: eyes closed on solid surface and eyes open or closed on a foam support surface. When using ABE subjects received a unique, nonlinear frequency- and volumemodulation of stereo sound that represented the anterior-posterior(AP) and medial-lateral- displacement and velocity of trunk sway [1]. Results: ABF significantly reduced postural sway more in BVL subjects (39%, SE ±7.51) than control subjects (28%, SE ±4.23) when standing on foam with eyes closed. The benefit from ABF
Use of real-time bandwidth kinematic feedback in learning a cyclical lower limb movement skill
M. Hanlon, R. Anderson. Biomechanics Research Unit, University
of Limerick, Ireland
of young healthy subjects. These results also stress usefulness of coordinated head movements during balance exercises at unstable surface.
•
Introduction: Simple bandwidth feedback (SBF) tells when per-
formance is within or outside prescribed limits [1]. This study investigates the use of real-time SBF of knee angle in learning a novel cyclical lower limb movement skill. Methods: Sixteen healthy adult volunteers gave informed consent to participate in the study for 4 weeks (2 sessions/week). Each session consisted of 50 SBF training trials where subjects attempted to learn and accurately replicate a 4-second movement of the fight leg in the sagittal plane followed by 5 non-feedback retention trials. An instrumented knee brace provided real-time values for the subject's knee angle (at 50 Hz). This allowed comparison of the subject's movement to the ideal values. During the 4-second movement, SBF was given via two indicators, one triggered at every instant the subject's knee angle was above the prescribed limit, another at every instant the subject's knee angle was below the prescribed limit. Results: Early results (n 6) show a 49±32% reduction in error during feedback trials from session 1 to 6 and a 26±21% reduction in error during non-feedback trials from session 1 to 6. Full results will follow as training is still in progress. Discussion: Steady performance improvements can be made when learning a novel skill with relatively simple feedback which just indicates when the movement is outside prescribed bands, but not the amplitude of the error. Further training may be required to learn to accurately carry out skill when feedback is removed. Gait rehabilitation could benefit from similar techniques. Funding for this research is provided by the Irish Research Council for Science, Engineering and Technology: funded by the National Development Plan.
References [1] Schiffman JM, Luchies CW, Richards LG, Zebas CJ. The effects of age and feedback on isometric knee extensor force control abilities. Clin Biomech 2002; 17:486 493.
$131
Inverse-dynamics based assessment of walking using a robotic gait orthosis
J.M. Hidler 1'2, S. Goldberg 1'3. 1Center for Applied Biomechanics
and Rehabilitation Research, National Rehabilitation Hospital, Washington, DC, USA; 2Department of Biomedical Engineering, Catholic University, Washington, DC, USA; 3PhysicalDisabilities Branch, National Institutes of Health, Bethesda, MD, USA Introduction: The goal of this work is to develop a quantitative method for evaluating walking performance in individuals with significant gait impairments during robotic-assisted gait training. The ability to monitor walking performance under various training conditions will, for the first time, provide therapists the information necessary to establish the optimal training parameters for maximizing patient recovery. Methods: The device used in this study is a Lokomat ® roboticgait orthosis [1], which actively assists leg movements during bodyweight supported treadmill training. The leg curls that couple the subject to the Lokomat have been modified with six-axis force sensors to record interaction forces, while an ADAL3D treadmill is used to record ground reaction forces and centers of pressure. Using these kinetic data along with measured joint kinematics, a real-time inverse dynamics technique [2] has been developed to quantify ankle, knee, and hip moments exerted by the subject while ambulating on the treadmill within the Lokomat. Results: The proposed technique is now being tested using healthy individuals with no gait disorders, where we are evaluating the sensitivity of the predicted joint moments on important anatomical measures, including leg centers of mass, inertial components, and joint w~es of rotation. Conclusions: Using this technique, we will study the influence of key gait training parameters such as walking speed and level of body-weight support on stepping ability in individuals following neurological injury.
References I2~
The effects of four weeks aerotrim ® training period on postural balance
H. Hannola 1, H. Pekkarinen 2. 1Rovaniemi Polytechnic, School of Sports' and Leisure, Rovaniemi, Finland," 2University of Kuopio, Faculty of Medicine, Kuopio, Finland Introduction: Sufficient ability to maintain static and dynamic balance is necessary both in world-class sports and normal daily living. The purpose of this study was to examine the effects of four weeks Aerotfim ® training period on postural balance. Methods: Twenty-six sport instructor students participated in this study. Students were divided into two groups, test group (n 13) and control group (n 13). Postural stability was assessed using Head Shake Sensory Organization Test (HS-SOT) on the NeuroCom SmartEquitest. Test group was training for four weeks, three times ® a week, with Aerotfim training equipment. After this intervention postural stability was assessed again. The differences between assessments were statistically calculated using a paired samples t-test design. Results: The results of the study indicate that head motions at unstable surface significantly decrease equilibrium scores of normal subjects. They also indicate that four weeks Aerotfim ® training period significantly improves the HS-SOT equilibrium scores under altered support surface conditions. Discussion and Conclusions: Preliminary published results indicate that the HS-SOT does significantly expand the sensitivity and utility of the standard Sensory Organization Test (SOT). This study also indicated that especially HS-SOT under altered support surface conditions is sensitive enough to differentiate balance abilities
[1] Colombo G, Joerg M, Schreier R, Dietz V. Treadmill training of paraplegic patients using a robotic orthosis. Journal of Rehabilitation Research and Development 2000; 37:693 700. [2] Winter D, Biomechanics and motor control of human movement, John Wiley & Sons, 1990.
•
Audio biofeedback: sensory substitution for vestibular loss
EB. Horak 1, M. Dozza 1'2, L. Chiafi 2. 1Neurological Sciences' Institute, Oregon Health & Science University, Beaverton, OR, USA; 2Dept. of Electronics Computer Science and Systems, University of Bologna, Bologna, Italy Introduction: This study tests the hypothesis that audio-biofeedback
(ABF) signaling accelerations related to body center of mass movements can provide an effective and specific sensory substitution for loss of vestibular information. Methods: We quantified the effects of ABF on standing postural sway (center of foot pressure area) of 9 subjects with profound, bilateral loss of vestibular function (BVL) and 9 age-matched, healthy control subjects under 3 conditions: eyes closed on solid surface and eyes open or closed on a foam support surface. When using ABE subjects received a unique, nonlinear frequency- and volumemodulation of stereo sound that represented the anterior-posterior(AP) and medial-lateral- displacement and velocity of trunk sway [1]. Results: ABF significantly reduced postural sway more in BVL subjects (39%, SE ±7.51) than control subjects (28%, SE ±4.23) when standing on foam with eyes closed. The benefit from ABF