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Senatore SC, Takahashi KZ, Malcolm P. Using human-in-the-loop optimization for guiding manual prosthesis adjustments: a proof-of-concept study. Front Robot AI 2023; 10:1183170. [PMID: 37538962 PMCID: PMC10394618 DOI: 10.3389/frobt.2023.1183170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 06/28/2023] [Indexed: 08/05/2023] Open
Abstract
Introduction: Human-in-the-loop optimization algorithms have proven useful in optimizing complex interactive problems, such as the interaction between humans and robotic exoskeletons. Specifically, this methodology has been proven valid for reducing metabolic cost while wearing robotic exoskeletons. However, many prostheses and orthoses still consist of passive elements that require manual adjustments of settings. Methods: In the present study, we investigated if human-in-the-loop algorithms could guide faster manual adjustments in a procedure similar to fitting a prosthesis. Eight healthy participants wore a prosthesis simulator and walked on a treadmill at 0.8 ms-1 under 16 combinations of shoe heel height and pylon height. A human-in-the-loop optimization algorithm was used to find an optimal combination for reducing the loading rate on the limb contralateral to the prosthesis simulator. To evaluate the performance of the optimization algorithm, we used a convergence criterium. We evaluated the accuracy by comparing it against the optimum from a full sweep of all combinations. Results: In five out of the eight participants, the human-in-the-loop optimization reduced the time taken to find an optimal combination; however, in three participants, the human-in-the-loop optimization either converged by the last iteration or did not converge. Discussion: Findings from this study show that the human-in-the-loop methodology could be helpful in tasks that require manually adjusting an assistive device, such as optimizing an unpowered prosthesis. However, further research is needed to achieve robust performance and evaluate applicability in persons with amputation wearing an actual prosthesis.
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Affiliation(s)
- Siena C. Senatore
- Biomechanics Research Building, University of Nebraska at Omaha, Omaha, NE, United States
| | - Kota Z. Takahashi
- Department of Health and Kinesiology, University of Utah, Salt Lake City, UT, United States
| | - Philippe Malcolm
- Biomechanics Research Building, University of Nebraska at Omaha, Omaha, NE, United States
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Tiwari A, Kujur A, Kumar J, Joshi D. Investigating the Effect of Real-Time Center of Pressure (CoP) Feedback Training on the Swing Phase of Lower Limb Kinematics in Transfemoral Prostheses with SACH foot. J Biomech Eng 2021; 144:1130976. [PMID: 34951460 DOI: 10.1115/1.4053364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Indexed: 11/08/2022]
Abstract
Transfemoral amputee often encounters reduced toe clearance resulting in trip-related falls. Swing phase joint angles have been shown to influence the toe clearance therefore, training intervention that targets shaping the swing phase joint angles can potentially enhance toe clearance. The focus of this study was to investigate the effect of the shift in the location of the center of pressure (CoP) during heel strike on modulation of the swing phase joint angles in able-bodied participants (n=6) and transfemoral amputees (n=3). We first developed a real-time CoP-based visual feedback system such that participants could shift the CoP during treadmill walking. Next, the kinematic data were collected during two different walking sessions- baseline (without feedback) and feedback (shifting the CoP anteriorly/posteriorly at heel strike to match the target CoP location). Primary swing phase joint angle adaptations were observed with feedback such that during the mid-swing phase, posterior CoP shift feedback significantly increases (p<0.05) the average hip and knee flexion angle by 11.55 degrees and 11.86 degrees respectively in amputees, whereas a significant increase (p<0.05) in ankle dorsiflexion, hip and knee flexion angle by 3.60 degrees, 3.22 degrees, and 1.27 degrees respectively compared to baseline was observed in able-bodied participants. Moreover, an opposite kinematic adaptation was seen during anterior CoP shift feedback. Overall, results confirm a direct correlation between the CoP shift and the modulation in the swing phase lower limb joint angles.
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Affiliation(s)
- Ashutosh Tiwari
- Centre for Biomedical Engineering, Indian Institute of Technology Delhi, New Delhi 110016, India; Department of Biomedical Engineering, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Abhijeet Kujur
- Department of Design, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Jyoti Kumar
- Department of Design, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Deepak Joshi
- Centre for Biomedical Engineering, Indian Institute of Technology Delhi, New Delhi 110016, India; Department of Biomedical Engineering, All India Institute of Medical Sciences, New Delhi, 110029, India
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Tiwari A, Joshi D. Design and Validation of a Real-Time Visual Feedback System to Improve Minimum Toe Clearance (mTC) in Transfemoral Amputees. IEEE Trans Neural Syst Rehabil Eng 2021; 29:1711-1722. [PMID: 34398756 DOI: 10.1109/tnsre.2021.3105139] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Tripping is accompanied by reduced minimum toe clearance (mTC) during the swing phase of gait. The risk of fall due to tripping among transfemoral amputees is nearly 67% which is greater than the transtibial amputees. Therefore, intervention to improve mTC can potentially enhance the quality of life among transfemoral amputees. In this paper, we first develop a real-time visual feedback system with center of pressure (CoP) information. Next, we recruited six non-disabled and three transfemoral amputees to investigate the effect on mTC while participants were trained to shift the CoP anteriorly/posteriorly during heel strike. Finally, to assess the lasting effect of training on mTC, retention trials were conducted without feedback. During feedback, posterior shift in the CoP improved the mTC significantly from 4.68 ± 0.40 cm to 6.12 ± 0.68 cm (p < 0.025) in non-disabled participants. A similar significant improvement in mTC from 4.60 ± 0.55 cm to 5.62 ± 0.57 cm was observed in amputees during posterior shift of CoP. Besides mTC, maximal toe clearances, i.e., maxTC1 and maxTC2, also showed a significant increase (p < 0.025) during the posterior shift of CoP in both the participants. Moreover, during retention, mTC did not differ significantly (p > 0.05) from feedback condition in amputee, suggesting a positive effect of feedback training. The foot-to-ground angle (FGA) at mTC increased significantly (p < 0.025) during posterior shift feedback in non-disabled suggests active ankle dorsiflexion in increasing mTC. However, in amputees, FGA at mTC did not differ significantly during both anterior and posterior CoP shift feedback. The present findings suggest CoP feedback as a potential strategy during gait rehabilitation of transfemoral amputees.
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Rhythmic neural activity is comodulated with short-term gait modifications during first-time use of a dummy prosthesis: a pilot study. J Neuroeng Rehabil 2020; 17:134. [PMID: 33032621 PMCID: PMC7542708 DOI: 10.1186/s12984-020-00761-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 09/16/2020] [Indexed: 01/10/2023] Open
Abstract
Background After transfemoral amputation, many hours of practice are needed to re-learn walking with a prosthesis. The long adaptation process that consolidates a novel gait pattern seems to depend on cerebellar function for reinforcement of specific gait modifications, but the precise, step-by-step gait modifications (e.g., foot placement) most likely rely on top-down commands from the brainstem and cerebral cortex. The aim of this study was to identify, in able-bodied individuals, the specific modulations of cortical rhythms that accompany short-term gait modifications during first-time use of a dummy prosthesis. Methods Fourteen naïve participants walked on a treadmill without (one block, 4 min) and with a dummy prosthesis (three blocks, 3 × 4 min), while ground reaction forces and 32-channel EEG were recorded. Gait cycle duration, stance phase duration, step width, maximal ground reaction force and, ground reaction force trace over time were measured to identify gait modifications. Independent component analysis of EEG data isolated brain-related activity from distinct anatomical sources. The source-level data were segmented into gait cycles and analyzed in the time–frequency domain to reveal relative enhancement or suppression of intrinsic cortical oscillations. Differences between walking conditions were evaluated with one-way ANOVA and post-hoc testing (α = 0.05). Results Immediate modifications occurred in the gait parameters when participants were introduced to the dummy prosthesis. Except for gait cycle duration, these modifications remained throughout the duration of the experimental session. Power modulations of the theta, mu, beta, and gamma rhythms, of sources presumably from the fronto-central and the parietal cortices, were found across the experimental session. Significant power modulations of the theta, beta, and gamma rhythms within the gait cycle were predominately found around the heel strike of both feet and the swing phase of the right (prosthetic) leg. Conclusions The modulations of cortical activity could be related to whole-body coordination, including the swing phase and placing of the prosthesis, and the bodyweight transfer between legs and arms. Reduced power modulation of the gamma rhythm within the experimental session may indicate initial motor memories being formed. Better understanding of the sensorimotor processes behind gait modifications may inform the development of neurofeedback strategies to assist gait rehabilitation.
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Hisano G, Hashizume S, Kobayashi Y, Murai A, Kobayashi T, Nakashima M, Hobara H. Factors associated with a risk of prosthetic knee buckling during walking in unilateral transfemoral amputees. Gait Posture 2020; 77:69-74. [PMID: 31999980 DOI: 10.1016/j.gaitpost.2020.01.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 12/06/2019] [Accepted: 01/02/2020] [Indexed: 02/02/2023]
Abstract
BACKGROUND Walking and mobility are essential for a satisfactory quality of life. However, individuals with transfemoral amputations have difficulties in preventing falls due to prosthetic knee buckling, defined as the sudden loss of postural support during weight-bearing activities. The risk of prosthetic knee buckling can be evaluated by determining the prosthetic knee angular impulse (PKAI) during the early stance phase. However, little is known about the factors associated with PKAI in individuals with unilateral transfemoral amputations. RESEARCH QUESTION What are the demographic factors that can be associated with the risk of prosthetic knee buckling, quantified by PKAI, during walking in individuals with unilateral transfemoral amputations? METHODS Thirteen individuals with unilateral transfemoral amputations were instructed to perform level walking at a comfortable, self-selected speed on a straight, 10-m walkway. PKAI was calculated as the time integral of the prosthetic knee external flexion-extension moment during the initial 40 % of the prosthetic gait cycle. We used Pearson's correlation coefficients to examine the relationship of PKAI with the following variables: the subject's body height, body mass, and age; the time since amputation; and the current prosthesis use history. Furthermore, an independentt-test was used to compare PKAI according to the sex (male vs. female) and etiology (trauma vs. nontrauma). RESULTS PKAI exhibited a significant negative linear relationship with the subject's body height and body mass. However, it showed no significant correlation with age, the time since amputation, and the current prosthesis use history. It was also significantly greater in women than in men and was not significantly influenced by the etiology. SIGNIFICANCE Awareness about demographic factors associated with PKAI during walking can contribute to fall assessments in gait rehabilitation programs for individuals with unilateral transfemoral amputations.
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Affiliation(s)
- Genki Hisano
- Department of Systems and Control Engineering, Tokyo Institute of Technology, Tokyo, Japan; Artificial Intelligence Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tokyo, Japan
| | - Satoru Hashizume
- Department of Systems and Control Engineering, Tokyo Institute of Technology, Tokyo, Japan
| | - Yoshiyuki Kobayashi
- Human Augmentation Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tokyo, Japan
| | - Akihiko Murai
- Human Augmentation Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tokyo, Japan
| | - Toshiki Kobayashi
- Department of Prosthetics and Orthotics, Faculty of Health Sciences, Hokkaido University of Science, Sapporo, Hokkaido, Japan
| | - Motomu Nakashima
- Department of Systems and Control Engineering, Tokyo Institute of Technology, Tokyo, Japan
| | - Hiroaki Hobara
- Artificial Intelligence Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tokyo, Japan.
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Schlafly M, Reed KB. Novel passive ankle-foot prosthesis mimics able-bodied ankle angles and ground reaction forces. Clin Biomech (Bristol, Avon) 2020; 72:202-210. [PMID: 31991286 DOI: 10.1016/j.clinbiomech.2019.12.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 04/24/2019] [Accepted: 12/17/2019] [Indexed: 02/07/2023]
Abstract
BACKGROUND During gait, the human ankle both bends with ease and provides push-off forces that facilitate forward motion. The ankle is crucial for support, stabilization, and adapting to different slopes and terrains. Individuals with lower limb amputation require an ankle-foot prosthesis for basic mobility. METHODS Inspired by the role of the ankle-foot in an able-bodied gait, the 3D printed Compliant and Articulating Prosthetic Ankle (CAPA) foot was designed. It consists of four articulating components connected by torsion springs and produces forces that are dependent on the ankle angle. Using the Computer Assisted Rehabilitation Environment, able-bodied individuals walked wearing a prosthetic simulator with the Solid Ankle Cushioned Heel foot, Renegade® AT, and multiple versions of the CAPA. These versions test compliant vs. stiff, small vs. large rocker radius, and pretension vs. none. We hypothesized that the CAPA would have larger ankle range of motion, push-off forces, and braking forces. FINDINGS Compared to existing prostheses, the novel prosthesis exhibits greater and significantly different ankle range of motion and sagittal plane ground reaction forces than existing prostheses during gait. Nine out of ten individuals prefer the novel prosthesis to the existing prostheses, and there is a statistically significant difference in difficulty level ratings. INTERPRETATION By providing a personalizable and passive alternative to existing designs, the CAPA could improve the quality of life for the growing number of individuals living with limb loss in the United States and around the world.
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Affiliation(s)
- Millicent Schlafly
- Rehabilitation Engineering and Electromechanical Design Lab, Department of Mechanical Engineering, University of South Florida, United States.
| | - Kyle B Reed
- Rehabilitation Engineering and Electromechanical Design Lab, Department of Mechanical Engineering, University of South Florida, United States.
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Koehler-McNicholas SR, Lipschutz RD, Gard SA. The biomechanical response of persons with transfemoral amputation to variations in prosthetic knee alignment during level walking. ACTA ACUST UNITED AC 2018; 53:1089-1106. [PMID: 28355034 DOI: 10.1682/jrrd.2014.12.0311] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 09/29/2015] [Indexed: 11/05/2022]
Abstract
Prosthetic alignment is an important factor in the overall fit and performance of a lower-limb prosthesis. However, the association between prosthetic alignment and control strategies used by persons with transfemoral amputation to coordinate the movement of a passive prosthetic knee is poorly understood. This study investigated the biomechanical response of persons with transfemoral amputation to systematic perturbations in knee joint alignment during a level walking task. Quantitative gait data were collected for three alignment conditions: bench alignment, 2 cm anterior knee translation (ANT), and 2 cm posterior knee translation (POST). In response to a destabilizing alignment perturbation (i.e., the ANT condition), participants significantly increased their early-stance hip extension moment, confirming that persons with transfemoral amputation rely on a hip extensor strategy to maintain knee joint stability. However, participants also decreased the rate at which they loaded their prosthesis, decreased their affected-side step length, increased their trunk flexion, and maintained their prosthesis in a more vertical posture at the time of opposite toe off. Collectively, these results suggest that persons with transfemoral amputation rely on a combination of strategies to coordinate stance-phase knee flexion. Further, comparatively few significant changes were observed in response to the POST condition, suggesting that a bias toward posterior alignment may have fewer implications in terms of stance-phase, knee joint control.
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Affiliation(s)
- Sara R Koehler-McNicholas
- Northwestern University Prosthetics-Orthotics Center, Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, IL.,Jesse Brown VA Medical Center, Chicago, IL
| | - Robert D Lipschutz
- Northwestern University Prosthetics-Orthotics Center, Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, IL.,Rehabilitation Institute of Chicago, Chicago, IL
| | - Steven A Gard
- Northwestern University Prosthetics-Orthotics Center, Department of Physical Medicine and Rehabilitation, Feinberg School of Medicine, Northwestern University, Chicago, IL.,Jesse Brown VA Medical Center, Chicago, IL
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Koehler SR, Dhaher YY, Hansen AH. Cross-validation of a portable, six-degree-of-freedom load cell for use in lower-limb prosthetics research. J Biomech 2014; 47:1542-7. [DOI: 10.1016/j.jbiomech.2014.01.048] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 01/30/2014] [Accepted: 01/31/2014] [Indexed: 11/16/2022]
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Criterion and construct validity of prosthesis-integrated measurement of joint moment data in persons with transtibial amputation. J Appl Biomech 2014; 30:431-8. [PMID: 24603673 DOI: 10.1123/jab.2013-0309] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Prosthesis-integrated sensors are appealing for use in clinical settings where gait analysis equipment is unavailable, but accurate knowledge of patients' performance is desired. Data obtained from load cells (inferring joint moments) may aid clinicians in the prescription, alignment, and gait rehabilitation of persons with limb loss. The purpose of this study was to assess the accuracy of prosthesis-integrated load cells for routine use in clinical practice. Level ground walking of persons with transtibial amputation was concurrently measured with a commercially available prosthesis-integrated load cell, a 10-camera motion analysis system, and piezoelectric force plates. Ankle and knee flexion/extension moments were derived and measurement methods were compared via correlation analysis. Pearson correlation coefficients ranged from 0.661 for ankle pronation/supination moments to 0.915 for ankle flexion/extension moments (P < .001). Root mean squared errors between measurement methods were in the magnitude of 10% of the measured range and were explainable. Differences in results depicted differences between systems in definition and computation of measurement variables. They may not limit clinical use of the load cell, but should be considered when data are compared directly to conventional gait analysis data. Construct validity of the load cell (ie, ability to measure joint moments in-situ) is supported by the study results.
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