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Harshe K, Conner BC, Lerner ZF. Predicting Steady-State Metabolic Power in Cerebral Palsy, Stroke, and the Elderly During Walking With and Without Assistive Devices. Ann Biomed Eng 2024:10.1007/s10439-024-03614-w. [PMID: 39245696 DOI: 10.1007/s10439-024-03614-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Accepted: 09/01/2024] [Indexed: 09/10/2024]
Abstract
PURPOSE Individuals with walking impairment, such as those with cerebral palsy, often face challenges in leading physically active lives due to the high energy cost of movement. Assistive devices like powered exoskeletons aim to alleviate this burden and improve mobility. Traditionally, optimizing the effectiveness of such devices has relied on time-consuming laboratory-based measurements of energy expenditure, which may not be feasible for some patient populations. To address this, our study aimed to enhance the state-of-the-art predictive model for estimating steady-state metabolic rate from 2-min walking trials to include individuals with and without walking disabilities and for a variety of terrains and wearable device conditions. METHODS Using over 200 walking trials collected from eight prior exoskeleton-related studies, we trained a simple linear machine learning model to predict metabolic power at steady state based on condition-specific factors, such as whether the trial was conducted on a treadmill (level or incline) or outdoors, as well as demographic information, such as the participant's weight or presence of walking impairment, and 2 minutes of metabolic data. RESULTS We demonstrated the ability to predict steady-state metabolic rate to within an accuracy of 4.71 ± 2.7% on average across all walking conditions and patient populations, including with assistive devices and on different terrains. CONCLUSION This work seeks to unlock the use of in-the-loop optimization of wearable assistive devices in individuals with limited walking capacity. A freely available MATLAB application allows other researchers to easily apply our model.
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Affiliation(s)
- Karl Harshe
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ, 86001, USA
| | - Benjamin C Conner
- College of Medicine - Phoenix, University of Arizona, Phoenix, AZ, USA
| | - Zachary F Lerner
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ, 86001, USA.
- College of Medicine - Phoenix, University of Arizona, Phoenix, AZ, USA.
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Bowersock CD, Lerner ZF. Comparing the effectiveness of robotic plantarflexion resistance and biofeedback between overground and treadmill walking. J Biomech 2024; 175:112282. [PMID: 39182263 DOI: 10.1016/j.jbiomech.2024.112282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 07/22/2024] [Accepted: 08/16/2024] [Indexed: 08/27/2024]
Abstract
Individuals with diminished walking performance caused by neuromuscular impairments often lack plantar flexion muscle activity. Robotic devices have been developed to address these issues and increase walking performance. While these devices have shown promise in their ability to increase musculature engagement of the lower limbs when used on a treadmill, most have not been developed or validated for overground walking and community use. Overground walking may limit the effectiveness of robotic devices due to differences in gait characteristics between walking terrains and reduced user engagement. The purpose of this study was to validate our multimodal robotic gait training system for overground walking in individuals with neuromuscular gait impairments. This untethered wearable robotic device can provide an ankle resistive torque proportional to the users' biological ankle torque. The device can also provide audio biofeedback based on users' plantar pressure intending to increase ankle power and muscle activity of the plantar flexors. Seven individuals with cerebral palsy participated. Participants walked overground and on a treadmill with our robotic gait training system in a single testing session. Results showed all seven participants to increase peak plantar flexor muscle activity, 10.3% on average, when walking with the gait trainer overground compared to treadmill. When compared to typical baseline overground walking, overground gait trainer use caused individuals to have slightly less knee joint excursion (3°) and moderately more ankle joint excursion (7°). This work supports our vision of using the wearable robotic device as a gait aid and rehabilitation tool in the home and community settings.
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Affiliation(s)
- Collin D Bowersock
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ, United States.
| | - Zachary F Lerner
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ, United States; College of Medicine - Phoenix, University of Arizona, Phoenix, AZ, United States.
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3
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Devine TM, Alter KE, Damiano DL, Bulea TC. A randomized cross-over study protocol to evaluate long-term gait training with a pediatric robotic exoskeleton outside the clinical setting in children with movement disorders. PLoS One 2024; 19:e0304087. [PMID: 38976710 PMCID: PMC11230531 DOI: 10.1371/journal.pone.0304087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 05/02/2024] [Indexed: 07/10/2024] Open
Abstract
Individuals with neuromuscular disorders display a combination of motor control deficits and lower limb weakness contributing to knee extension deficiency characterized by exaggerated stance phase knee flexion. There is a lack of evidence for long-term improvement of knee extension deficiency with currently available clinical treatment programs. Our previous work testing a wearable robotic exoskeleton with precisely timed assistive torque applied at the knee showed immediate increases in knee extension during walking for children with cerebral palsy, which continued to improve over an acute practice period. When we applied interleaved assistance and resistance to knee extension, we observed improvements in knee extension and increased muscle activation indicating the potential for muscle strengthening when used over time. There is a need for additional, high-quality trials to assess the impact of dosage, intensity and volume of training necessary to see persistent improvement in lower limb function for these patient populations. This randomized crossover study (ClinicalTrials.gov: NCT05726591) was designed to determine whether 12 weeks of overground gait training with a robotic exoskeleton outside of the clinical setting, following an initial in clinic accommodation period, has a beneficial effect on walking ability, muscle activity and overall motor function. Participants will be randomized to either complete the exoskeleton intervention or continue their standard therapy for 12 weeks first, followed by a crossover to the other study component. The primary outcome measure is change in peak knee extension angle during walking; secondary outcome measures include gait speed, strength, and validated clinical scales of motor function and mobility. Assessments will be completed before and after the intervention and at 6 weeks post-intervention, and safety and compliance will be monitored throughout. We hypothesize that the 12-week exoskeleton intervention outside the clinical setting will show greater improvements in study outcome measures than the standard therapy.
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Affiliation(s)
- Taylor M. Devine
- Rehabilitation Medicine Department, National Institutes of Health Clinical Center, Bethesda, Maryland, United States of America
| | - Katharine E. Alter
- Rehabilitation Medicine Department, National Institutes of Health Clinical Center, Bethesda, Maryland, United States of America
| | - Diane L. Damiano
- Rehabilitation Medicine Department, National Institutes of Health Clinical Center, Bethesda, Maryland, United States of America
| | - Thomas C. Bulea
- Rehabilitation Medicine Department, National Institutes of Health Clinical Center, Bethesda, Maryland, United States of America
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Buccilli B. Exploring new horizons: Emerging therapeutic strategies for pediatric stroke. Exp Neurol 2024; 374:114701. [PMID: 38278205 DOI: 10.1016/j.expneurol.2024.114701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 12/31/2023] [Accepted: 01/23/2024] [Indexed: 01/28/2024]
Abstract
Pediatric stroke presents unique challenges, and optimizing treatment strategies is essential for improving outcomes in this vulnerable population. This review aims to provide an overview of new, innovative, and potential treatments for pediatric stroke, with a primary objective to stimulate further research in this field. Our review highlights several promising approaches in the realm of pediatric stroke management, including but not limited to stem cell therapy and robotic rehabilitation. These innovative interventions offer new avenues for enhancing functional recovery, reducing long-term disability, and tailoring treatments to individual patient needs. The findings of this review underscore the importance of ongoing research and development of innovative treatments in pediatric stroke. These advancements hold significant clinical relevance, offering the potential to improve the lives of children affected by stroke by enhancing the precision, efficacy, and accessibility of therapeutic interventions. Embracing these innovations is essential in our pursuit of better outcomes and a brighter future for pediatric stroke care.
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Affiliation(s)
- Barbara Buccilli
- Icahn School of Medicine at Mount Sinai, Department of Neurosurgery, 1 Gustave L. Levy Pl, New York, NY 10029, United States of America.
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Dierwechter B, Kolakowsky-Hayner SA. Journey to 1 Million Steps: A Retrospective Case Series Analyzing the Implementation of Robotic-Assisted Gait Training Into an Outpatient Pediatric Clinic. Pediatr Phys Ther 2024; 36:285-293. [PMID: 38349640 DOI: 10.1097/pep.0000000000001097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/16/2024]
Abstract
PURPOSE To describe the implementation of an exoskeleton program in a rehabilitation setting using a Design Thinking framework. METHODS This is a retrospective case series of 3 randomly selected children who participated in skilled physical therapy using a pediatric exoskeleton that occurred on our journey to walking 1 000 000 steps in the exoskeleton devices. Participants ranged in age from 3 to 5 years, and all had neurologic disorders. RESULTS All participants improved toward achieving their therapy goals, tolerated the exoskeleton well, and had an increased number of steps taken over time. CONCLUSION The implementation of new technology into pediatric care and an established outpatient therapy clinic is described. The Design Thinking process applies to health care professionals and improves clinical care. Exoskeletons are effective tools for use in pediatric physical therapy.
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Affiliation(s)
- Brittany Dierwechter
- Outpatient Physical Therapy Department (Dr Dierwechter) and Research and Clinical Outcomes Department (Dr Kolakowsky-Hayner), Good Shepherd Rehabilitation Network, Allentown, Pennsylvania
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Kuska EC, Steele KM. Does crouch alter the effects of neuromuscular impairments on gait? A simulation study. J Biomech 2024; 165:112015. [PMID: 38394953 PMCID: PMC10939721 DOI: 10.1016/j.jbiomech.2024.112015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 12/18/2023] [Accepted: 02/19/2024] [Indexed: 02/25/2024]
Abstract
Cerebral palsy (CP) is a neurologic injury that impacts control of movement. Individuals with CP also often develop secondary impairments like weakness and contracture. Both altered motor control and secondary impairments influence how an individual walks after neurologic injury. However, understanding the complex interactions between and relative effects of these impairments makes analyzing and improving walking capacity in CP challenging. We used a sagittal-plane musculoskeletal model and neuromuscular control framework to simulate crouch and nondisabled gait. We perturbed each simulation by varying the number of synergies controlling each leg (altered control), and imposed weakness and contracture. A Bayesian Additive Regression Trees (BART) model was also used to parse the relative effects of each impairment on the muscle activations required for each gait pattern. By using these simulations to evaluate gait-pattern specific effects of neuromuscular impairments, we identified some advantages of crouch gait. For example, crouch tolerated 13 % and 22 % more plantarflexor weakness than nondisabled gait without and with altered control, respectively. Furthermore, BART demonstrated that plantarflexor weakness had twice the effect on total muscle activity required during nondisabled gait than crouch gait. However, crouch gait was also disadvantageous in the presence of vasti weakness: crouch gait increased the effects of vasti weakness on gait without and with altered control. These simulations highlight gait-pattern specific effects and interactions between neuromuscular impairments. Utilizing computational techniques to understand these effects can elicit advantages of gait deviations, providing insight into why individuals may select their gait pattern and possible interventions to improve energetics.
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Affiliation(s)
- Elijah C Kuska
- Department of Mechanical Engineering, University of Washington, Seattle, WA, United States.
| | - Katherine M Steele
- Department of Mechanical Engineering, University of Washington, Seattle, WA, United States
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Spomer AM, Conner BC, Schwartz MH, Lerner ZF, Steele KM. Audiovisual biofeedback amplifies plantarflexor adaptation during walking among children with cerebral palsy. J Neuroeng Rehabil 2023; 20:164. [PMID: 38062454 PMCID: PMC10704679 DOI: 10.1186/s12984-023-01279-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 11/01/2023] [Indexed: 12/18/2023] Open
Abstract
BACKGROUND Biofeedback is a promising noninvasive strategy to enhance gait training among individuals with cerebral palsy (CP). Commonly, biofeedback systems are designed to guide movement correction using audio, visual, or sensorimotor (i.e., tactile or proprioceptive) cues, each of which has demonstrated measurable success in CP. However, it is currently unclear how the modality of biofeedback may influence user response which has significant implications if systems are to be consistently adopted into clinical care. METHODS In this study, we evaluated the extent to which adolescents with CP (7M/1F; 14 [12.5,15.5] years) adapted their gait patterns during treadmill walking (6 min/modality) with audiovisual (AV), sensorimotor (SM), and combined AV + SM biofeedback before and after four acclimation sessions (20 min/session) and at a two-week follow-up. Both biofeedback systems were designed to target plantarflexor activity on the more-affected limb, as these muscles are commonly impaired in CP and impact walking function. SM biofeedback was administered using a resistive ankle exoskeleton and AV biofeedback displayed soleus activity from electromyography recordings during gait. At every visit, we measured the time-course response to each biofeedback modality to understand how the rate and magnitude of gait adaptation differed between modalities and following acclimation. RESULTS Participants significantly increased soleus activity from baseline using AV + SM (42.8% [15.1, 59.6]), AV (28.5% [19.2, 58.5]), and SM (10.3% [3.2, 15.2]) biofeedback, but the rate of soleus adaptation was faster using AV + SM biofeedback than either modality alone. Further, SM-only biofeedback produced small initial increases in plantarflexor activity, but these responses were transient within and across sessions (p > 0.11). Following multi-session acclimation and at the two-week follow-up, responses to AV and AV + SM biofeedback were maintained. CONCLUSIONS This study demonstrated that AV biofeedback was critical to increase plantarflexor engagement during walking, but that combining AV and SM modalities further amplified the rate of gait adaptation. Beyond improving our understanding of how individuals may differentially prioritize distinct forms of afferent information, outcomes from this study may inform the design and selection of biofeedback systems for use in clinical care.
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Affiliation(s)
- Alyssa M Spomer
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA.
- Gillette Children's, 200 University Avenue East, Stop 490105, St. Paul, MN, 55101, USA.
| | - Benjamin C Conner
- College of Medicine - Phoenix, University of Arizona, Phoenix, AZ, USA
| | - Michael H Schwartz
- Department of Orthopedic Surgery, University of Minnesota, Minneapolis, MN, USA
- Gillette Children's, 200 University Avenue East, Stop 490105, St. Paul, MN, 55101, USA
| | - Zachary F Lerner
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA
- Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ, USA
| | - Katherine M Steele
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA
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Conner BC, Spomer AM, Steele KM, Lerner ZF. Factors influencing neuromuscular responses to gait training with a robotic ankle exoskeleton in cerebral palsy. Assist Technol 2023; 35:463-470. [PMID: 36194197 PMCID: PMC10070554 DOI: 10.1080/10400435.2022.2121324] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/29/2022] [Indexed: 10/10/2022] Open
Abstract
A current limitation in the development of robotic gait training interventions is understanding the factors that predict responses to treatment. The purpose of this study was to explore the application of an interpretable machine learning method, Bayesian Additive Regression Trees (BART), to identify factors influencing neuromuscular responses to a resistive ankle exoskeleton in individuals with cerebral palsy (CP). Eight individuals with CP (GMFCS levels I - III, ages 12-18 years) walked with a resistive ankle exoskeleton over seven visits while we measured soleus activation. A BART model was developed using a predictor set of kinematic, device, study, and participant metrics that were hypothesized to influence soleus activation. The model (R2 = 0.94) found that kinematics had the largest influence on soleus activation, but the magnitude of exoskeleton resistance, amount of gait training practice with the device, and participant-level parameters also had substantial effects. To optimize neuromuscular engagement during exoskeleton training in individuals with CP, our analysis highlights the importance of monitoring the user's kinematic response, in particular, peak stance phase hip flexion and ankle dorsiflexion. We demonstrate the utility of machine learning techniques for enhancing our understanding of robotic gait training outcomes, seeking to improve the efficacy of future interventions.
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Affiliation(s)
- Benjamin C. Conner
- College of Medicine – Phoenix, University of Arizona, Phoenix, AZ 85004, USA
| | - Alyssa M. Spomer
- Department of Mechanical Engineering, University of Washington, Seattle, WA 98195, USA
| | - Katherine M. Steele
- Department of Mechanical Engineering, University of Washington, Seattle, WA 98195, USA
| | - Zachary F. Lerner
- College of Medicine – Phoenix, University of Arizona, Phoenix, AZ 85004, USA
- Department of Mechanical Engineering, Northern Arizona University, AZ 86011, USA
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Harshe K, Williams JR, Hocking TD, Lerner ZF. Predicting Neuromuscular Engagement to Improve Gait Training with a Robotic Ankle Exoskeleton. IEEE Robot Autom Lett 2023; 8:5055-5060. [PMID: 38283263 PMCID: PMC10812839 DOI: 10.1109/lra.2023.3291919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2024]
Abstract
The clinical efficacy of robotic rehabilitation interventions hinges on appropriate neuromuscular recruitment from the patient. The first purpose of this study was to evaluate the use of supervised machine learning techniques to predict neuromuscular recruitment of the ankle plantar flexors during walking with ankle exoskeleton resistance in individuals with cerebral palsy (CP). The second goal of this study was to utilize the predictive models of plantar flexor recruitment in the design of a personalized biofeedback framework intended to improve (i.e., increase) user engagement when walking with resistance. First, we developed and trained multilayer perceptrons (MLPs), a type of artificial neural network (ANN), utilizing features extracted exclusively from the exoskeleton's onboard sensors, and demonstrated 85-87% accuracy, on average, in predicting muscle recruitment from electromyography measurements. Next, our participants completed a gait training session while receiving audio-visual biofeedback of their personalized real-time planar flexor recruitment predictions from the online MLP. We found that adding biofeedback to resistance elevated plantar flexor recruitment by 24 16% compared to resistance alone. This study highlights the potential for online machine learning frameworks to improve the effectiveness and delivery of robotic rehabilitation systems in clinical populations.
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Affiliation(s)
- Karl Harshe
- Mechanical Engineering Department, Northern Arizona University, Flagstaff, AZ 86011 USA
| | - Jack R Williams
- Mechanical Engineering Department, Northern Arizona University, Flagstaff, AZ 86011 USA
| | - Toby D Hocking
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ 86011 USA
| | - Zachary F Lerner
- Mechanical Engineering Department, Northern Arizona University, Flagstaff, AZ 86011 USA, and also with the Department of Orthopedics, The University of Arizona College of Medicine-Phoenix, Phoenix, AZ 85004 USA
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Ebers MR, Rosenberg MC, Kutz JN, Steele KM. A machine learning approach to quantify individual gait responses to ankle exoskeletons. J Biomech 2023; 157:111695. [PMID: 37406604 DOI: 10.1016/j.jbiomech.2023.111695] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 06/14/2023] [Accepted: 06/19/2023] [Indexed: 07/07/2023]
Abstract
Predicting an individual's response to an exoskeleton and understanding what data are needed to characterize responses remains challenging. Specifically, we lack a theoretical framework capable of quantifying heterogeneous responses to exoskeleton interventions. We leverage a neural network-based discrepancy modeling framework to quantify complex changes in gait in response to passive ankle exoskeletons in nondisabled adults. Discrepancy modeling aims to resolve dynamical inconsistencies between model predictions and real-world measurements. Neural networks identified models of (i) Nominal gait, (ii) Exoskeleton (Exo) gait, and (iii) the Discrepancy (i.e., response) between them. If an Augmented (Nominal+Discrepancy) model captured exoskeleton responses, its predictions should account for comparable amounts of variance in Exo gait data as the Exo model. Discrepancy modeling successfully quantified individuals' exoskeleton responses without requiring knowledge about physiological structure or motor control: a model of Nominal gait augmented with a Discrepancy model of response accounted for significantly more variance in Exo gait (median R2 for kinematics (0.928-0.963) and electromyography (0.665-0.788), (p<0.042)) than the Nominal model (median R2 for kinematics (0.863-0.939) and electromyography (0.516-0.664)). However, additional measurement modalities and/or improved resolution are needed to characterize Exo gait, as the discrepancy may not comprehensively capture response due to unexplained variance in Exo gait (median R2 for kinematics (0.954-0.977) and electromyography (0.724-0.815)). These techniques can be used to accelerate the discovery of individual-specific mechanisms driving exoskeleton responses, thus enabling personalized rehabilitation.
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Affiliation(s)
- Megan R Ebers
- Department of Mechanical Engineering, University of Washington, Seattle, WA, 98195, USA.
| | - Michael C Rosenberg
- Department of Mechanical Engineering, University of Washington, Seattle, WA, 98195, USA; Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA, 30322, USA
| | - J Nathan Kutz
- Department of Applied Mathematics, University of Washington, Seattle, WA, 98195, USA
| | - Katherine M Steele
- Department of Mechanical Engineering, University of Washington, Seattle, WA, 98195, USA
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Swaminathan K, Porciuncula F, Park S, Kannan H, Erard J, Wendel N, Baker T, Ellis TD, Awad LN, Walsh CJ. Ankle-targeted exosuit resistance increases paretic propulsion in people post-stroke. J Neuroeng Rehabil 2023; 20:85. [PMID: 37391851 PMCID: PMC10314463 DOI: 10.1186/s12984-023-01204-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 06/15/2023] [Indexed: 07/02/2023] Open
Abstract
BACKGROUND Individualized, targeted, and intense training is the hallmark of successful gait rehabilitation in people post-stroke. Specifically, increasing use of the impaired ankle to increase propulsion during the stance phase of gait has been linked to higher walking speeds and symmetry. Conventional progressive resistance training is one method used for individualized and intense rehabilitation, but often fails to target paretic ankle plantarflexion during walking. Wearable assistive robots have successfully assisted ankle-specific mechanisms to increase paretic propulsion in people post-stroke, suggesting their potential to provide targeted resistance to increase propulsion, but this application remains underexamined in this population. This work investigates the effects of targeted stance-phase plantarflexion resistance training with a soft ankle exosuit on propulsion mechanics in people post-stroke. METHODS We conducted this study in nine individuals with chronic stroke and tested the effects of three resistive force magnitudes on peak paretic propulsion, ankle torque, and ankle power while participants walked on a treadmill at their comfortable walking speeds. For each force magnitude, participants walked for 1 min while the exosuit was inactive, 2 min with active resistance, and 1 min with the exosuit inactive, in sequence. We evaluated changes in gait biomechanics during the active resistance and post-resistance sections relative to the initial inactive section. RESULTS Walking with active resistance increased paretic propulsion by more than the minimal detectable change of 0.8 %body weight at all tested force magnitudes, with an average increase of 1.29 ± 0.37 %body weight at the highest force magnitude. This improvement corresponded to changes of 0.13 ± 0.03 N m kg- 1 in peak biological ankle torque and 0.26 ± 0.04 W kg- 1 in peak biological ankle power. Upon removal of resistance, propulsion changes persisted for 30 seconds with an improvement of 1.49 ± 0.58 %body weight after the highest resistance level and without compensatory involvement of the unresisted joints or limb. CONCLUSIONS Targeted exosuit-applied functional resistance of paretic ankle plantarflexors can elicit the latent propulsion reserve in people post-stroke. After-effects observed in propulsion highlight the potential for learning and restoration of propulsion mechanics. Thus, this exosuit-based resistive approach may offer new opportunities for individualized and progressive gait rehabilitation.
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Affiliation(s)
- Krithika Swaminathan
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA, 02134, USA
| | - Franchino Porciuncula
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA, 02134, USA
- Sargent College of Health and Rehabilitation Sciences, Boston University, Boston, MA, 02215, USA
| | - Sungwoo Park
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA, 02134, USA
| | - Harini Kannan
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA, 02134, USA
| | - Julien Erard
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA, 02134, USA
| | - Nicholas Wendel
- Sargent College of Health and Rehabilitation Sciences, Boston University, Boston, MA, 02215, USA
| | - Teresa Baker
- Sargent College of Health and Rehabilitation Sciences, Boston University, Boston, MA, 02215, USA
| | - Terry D Ellis
- Sargent College of Health and Rehabilitation Sciences, Boston University, Boston, MA, 02215, USA
| | - Louis N Awad
- Sargent College of Health and Rehabilitation Sciences, Boston University, Boston, MA, 02215, USA
| | - Conor J Walsh
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA, 02134, USA.
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12
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Washabaugh EP, Augenstein TE, Koje M, Krishnan C. Functional Resistance Training With Viscous and Elastic Devices: Does Resistance Type Acutely Affect Knee Function? IEEE Trans Biomed Eng 2023; 70:1274-1285. [PMID: 36240034 PMCID: PMC10170553 DOI: 10.1109/tbme.2022.3214773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVE Functional resistance training (FRT) during walking is an emerging approach for rehabilitating individuals with neuromuscular or orthopedic injuries. During FRT, wearable exoskeleton/braces can target resistance to a weakened leg joint; however, the resistive properties of the training depend on the type of resistive elements used in the device. Hence, this study was designed to examine how the biomechanical and neural effects of functional resistance training differ with viscous and elastic resistances during both treadmill and overground walking. METHODS Fourteen able-bodied individuals were trained on two separate sessions with two devices that provided resistance to the knee (viscous and elastic) while walking on a treadmill. We measured gait biomechanics and muscle activation during training, as well as kinematic aftereffects and changes in peripheral fatigue and neural excitability after training. RESULTS We found the resistance type differentially altered gait kinetics during training-elastic resistance increased knee extension during stance while viscous resistance primarily affected swing. Also, viscous resistance increased power generation while elastic resistance could increase power absorption. Both devices resulted in significant kinematic and neural aftereffects. However, overground kinematic aftereffects and neural excitability did not differ between devices. CONCLUSION Different resistance types can be used to alter gait biomechanics during training. While there were no resistance-specific changes in acute neural adaptation following training, it is still possible that prolonged and repeated training could produce differential effects. SIGNIFICANCE Resistance type alters the kinetics of functional resistance training. Prolonged and repeated training sessions on patients will be needed to further measure the effects of these devices.
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Affiliation(s)
| | - Thomas E. Augenstein
- Michigan Medicine, Department of Physical Medicine and Rehabilitation, Ann Arbor, MI, USA; University of Michigan, Robotics Institute, Ann Arbor, MI, USA
| | - Mary Koje
- Michigan Medicine, Department of Physical Medicine and Rehabilitation, Ann Arbor, MI, USA
| | - Chandramouli Krishnan
- Michigan Medicine, Department of Physical Medicine and Rehabilitation, Ann Arbor, MI, USA; University of Michigan, Robotics Institute, Ann Arbor, MI, USA
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Asín-Prieto G, Oliveira Barroso F, Martínez-Expósito A, Urendes E, Gonzalez-Vargas J, Moreno JC. Mechanical disturbances applied by motorized ankle foot orthosis to adapt ankle muscles activation—A validation study. Front Bioeng Biotechnol 2023; 11:1079027. [PMID: 37008040 PMCID: PMC10060880 DOI: 10.3389/fbioe.2023.1079027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 03/06/2023] [Indexed: 03/18/2023] Open
Abstract
Background: Reduced function of ankle muscles usually leads to impaired gait. Motorized ankle foot orthoses (MAFOs) have shown potential to improve neuromuscular control and increase volitional engagement of ankle muscles. In this study, we hypothesize that specific disturbances (adaptive resistance-based perturbations to the planned trajectory) applied by a MAFO can be used to adapt the activity of ankle muscles. The first goal of this exploratory study was to test and validate two different ankle disturbances based on plantarflexion and dorsiflexion resistance while training in standing still position. The second goal was to assess neuromuscular adaptation to these approaches, namely, in terms of individual muscle activation and co-activation of antagonists.Methods: Two ankle disturbances were tested in ten healthy subjects. For each subject, the dominant ankle followed a target trajectory while the contralateral leg was standing still: a) dorsiflexion torque during the first part of the trajectory (Stance Correlate disturbance—StC), and b) plantarflexion torque during the second part of the trajectory (Swing Correlate disturbance—SwC). Electromyography was recorded from the tibialis anterior (TAnt) and gastrocnemius medialis (GMed) during MAFO and treadmill (baseline) trials.Results: GMed (plantarflexor muscle) activation decreased in all subjects during the application of StC, indicating that dorsiflexion torque did not enhance GMed activity. On the other hand, TAnt (dorsiflexor muscle) activation increased when SwC was applied, indicating that plantarflexion torque succeeded in enhancing TAnt activation. For each disturbance paradigm, there was no antagonist muscle co-activation accompanying agonist muscle activity changes.Conclusion: We successfully tested novel ankle disturbance approaches that can be explored as potential resistance strategies in MAFO training. Results from SwC training warrant further investigation to promote specific motor recovery and learning of dorsiflexion in neural-impaired patients. This training can potentially be beneficial during intermediate phases of rehabilitation prior to overground exoskeleton-assisted walking. Decreased activation of GMed during StC might be attributed to the unloaded body weight in the ipsilateral side, which typically decreases activation of anti-gravity muscles. Neural adaptation to StC needs to be studied thoroughly in different postures in futures studies.
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Affiliation(s)
- Guillermo Asín-Prieto
- Neural Rehabilitation Group, Cajal Institute, Spanish National Research Council (CSIC), Madrid, Spain
- Gogoa Mobility Robots, Abadiño, Spain
| | - Filipe Oliveira Barroso
- Neural Rehabilitation Group, Cajal Institute, Spanish National Research Council (CSIC), Madrid, Spain
- *Correspondence: Filipe Oliveira Barroso,
| | - Aitor Martínez-Expósito
- Neural Rehabilitation Group, Cajal Institute, Spanish National Research Council (CSIC), Madrid, Spain
- Universidad Autónoma de Madrid, Madrid, Spain
| | - Eloy Urendes
- Departamento de Tecnologías de la Información, Escuela Politécnica Superior, Escuela Politécnica Superior, Universidad San Pablo-CEU, CEU Universities, Madrid, Spain
| | | | - Juan C. Moreno
- Neural Rehabilitation Group, Cajal Institute, Spanish National Research Council (CSIC), Madrid, Spain
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14
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de Miguel-Fernández J, Lobo-Prat J, Prinsen E, Font-Llagunes JM, Marchal-Crespo L. Control strategies used in lower limb exoskeletons for gait rehabilitation after brain injury: a systematic review and analysis of clinical effectiveness. J Neuroeng Rehabil 2023; 20:23. [PMID: 36805777 PMCID: PMC9938998 DOI: 10.1186/s12984-023-01144-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 01/07/2023] [Indexed: 02/21/2023] Open
Abstract
BACKGROUND In the past decade, there has been substantial progress in the development of robotic controllers that specify how lower-limb exoskeletons should interact with brain-injured patients. However, it is still an open question which exoskeleton control strategies can more effectively stimulate motor function recovery. In this review, we aim to complement previous literature surveys on the topic of exoskeleton control for gait rehabilitation by: (1) providing an updated structured framework of current control strategies, (2) analyzing the methodology of clinical validations used in the robotic interventions, and (3) reporting the potential relation between control strategies and clinical outcomes. METHODS Four databases were searched using database-specific search terms from January 2000 to September 2020. We identified 1648 articles, of which 159 were included and evaluated in full-text. We included studies that clinically evaluated the effectiveness of the exoskeleton on impaired participants, and which clearly explained or referenced the implemented control strategy. RESULTS (1) We found that assistive control (100% of exoskeletons) that followed rule-based algorithms (72%) based on ground reaction force thresholds (63%) in conjunction with trajectory-tracking control (97%) were the most implemented control strategies. Only 14% of the exoskeletons implemented adaptive control strategies. (2) Regarding the clinical validations used in the robotic interventions, we found high variability on the experimental protocols and outcome metrics selected. (3) With high grade of evidence and a moderate number of participants (N = 19), assistive control strategies that implemented a combination of trajectory-tracking and compliant control showed the highest clinical effectiveness for acute stroke. However, they also required the longest training time. With high grade of evidence and low number of participants (N = 8), assistive control strategies that followed a threshold-based algorithm with EMG as gait detection metric and control signal provided the highest improvements with the lowest training intensities for subacute stroke. Finally, with high grade of evidence and a moderate number of participants (N = 19), assistive control strategies that implemented adaptive oscillator algorithms together with trajectory-tracking control resulted in the highest improvements with reduced training intensities for individuals with chronic stroke. CONCLUSIONS Despite the efforts to develop novel and more effective controllers for exoskeleton-based gait neurorehabilitation, the current level of evidence on the effectiveness of the different control strategies on clinical outcomes is still low. There is a clear lack of standardization in the experimental protocols leading to high levels of heterogeneity. Standardized comparisons among control strategies analyzing the relation between control parameters and biomechanical metrics will fill this gap to better guide future technical developments. It is still an open question whether controllers that provide an on-line adaptation of the control parameters based on key biomechanical descriptors associated to the patients' specific pathology outperform current control strategies.
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Affiliation(s)
- Jesús de Miguel-Fernández
- Biomechanical Engineering Lab, Department of Mechanical Engineering and Research Centre for Biomedical Engineering, Universitat Politècnica de Catalunya, Diagonal 647, 08028 Barcelona, Spain
- Institut de Recerca Sant Joan de Déu, Santa Rosa 39-57, 08950 Esplugues de Llobregat, Spain
| | | | - Erik Prinsen
- Roessingh Research and Development, Roessinghsbleekweg 33b, 7522AH Enschede, Netherlands
| | - Josep M. Font-Llagunes
- Biomechanical Engineering Lab, Department of Mechanical Engineering and Research Centre for Biomedical Engineering, Universitat Politècnica de Catalunya, Diagonal 647, 08028 Barcelona, Spain
- Institut de Recerca Sant Joan de Déu, Santa Rosa 39-57, 08950 Esplugues de Llobregat, Spain
| | - Laura Marchal-Crespo
- Cognitive Robotics Department, Delft University of Technology, Mekelweg 2, 2628 Delft, Netherlands
- Motor Learning and Neurorehabilitation Lab, ARTORG Center for Biomedical Engineering Research, University of Bern, Freiburgstrasse 3, 3010 Bern, Switzerland
- Department of Rehabilitation Medicine, Erasmus MC University Medical Center, Doctor Molewaterplein 40, 3015 GD Rotterdam, The Netherlands
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15
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Zhou Y. Recent advances in wearable actuated ankle-foot orthoses: Medical effects, design, and control. Proc Inst Mech Eng H 2023; 237:163-178. [PMID: 36515408 DOI: 10.1177/09544119221142335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
This paper presents a survey on recent advances of wearable actuated ankle-foot orthoses (AAFOs). First of all, their medical functions are investigated. From the short-term aspect, they lead to rectification of pathological gaits, reduction of metabolic cost, and improvement of gait performance. After AAFO-based walking training with sufficient time, free walking performance can be enhanced. Then, key design factors are studied. First, primary design parameters are investigated. Second, common actuators are analysed. Third, human-robot interaction (HRI), ergonomics, safety, and application places, are considered. In the following section, control technologies are reviewed from the aspects of rehabilitation stages, gait feature quantities, and controller characteristics. Finally, existing problems are discussed; development trends are prospected.
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Affiliation(s)
- Yuan Zhou
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
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16
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Ebers MR, Rosenberg MC, Kutz JN, Steele KM. A machine learning approach to quantify individual gait responses to ankle exoskeletons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.20.524757. [PMID: 36711530 PMCID: PMC9882260 DOI: 10.1101/2023.01.20.524757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
We currently lack a theoretical framework capable of characterizing heterogeneous responses to exoskeleton interventions. Predicting an individual's response to an exoskeleton and understanding what data are needed to characterize responses has been a persistent challenge. In this study, we leverage a neural network-based discrepancy modeling framework to quantify complex changes in gait in response to passive ankle exoskeletons in nondisabled adults. Discrepancy modeling aims to resolve dynamical inconsistencies between model predictions and real-world measurements. Neural networks identified models of (i) Nominal gait, (ii) Exoskeleton ( Exo ) gait, and (iii) the Discrepancy ( i.e. , response) between them. If an Augmented (Nominal+Discrepancy) model captured exoskeleton responses, its predictions should account for comparable amounts of variance in Exo gait data as the Exo model. Discrepancy modeling successfully quantified individuals' exoskeleton responses without requiring knowledge about physiological structure or motor control: a model of Nominal gait augmented with a Discrepancy model of response accounted for significantly more variance in Exo gait (median R 2 for kinematics (0.928 - 0.963) and electromyography (0.665 - 0.788), ( p < 0.042)) than the Nominal model (median R 2 for kinematics (0.863 - 0.939) and electromyography (0.516 - 0.664)). However, additional measurement modalities and/or improved resolution are needed to characterize Exo gait, as the discrepancy may not comprehensively capture response due to unexplained variance in Exo gait (median R 2 for kinematics (0.954 - 0.977) and electromyography (0.724 - 0.815)). These techniques can be used to accelerate the discovery of individual-specific mechanisms driving exoskeleton responses, thus enabling personalized rehabilitation.
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Affiliation(s)
- Megan R Ebers
- Department of Mechanical Engineering, University of Washington, Seattle, WA, 98195, USA
| | - Michael C Rosenberg
- Department of Mechanical Engineering, University of Washington, Seattle, WA, 98195, USA
- Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA, 30322, USA
| | - J Nathan Kutz
- Department of Applied Mathematics, University of Washington, Seattle, WA, 98195, USA
| | - Katherine M Steele
- Department of Mechanical Engineering, University of Washington, Seattle, WA, 98195, USA
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17
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Hunt M, Everaert L, Brown M, Muraru L, Hatzidimitriadou E, Desloovere K. Effectiveness of robotic exoskeletons for improving gait in children with cerebral palsy: A systematic review. Gait Posture 2022; 98:343-354. [PMID: 36306544 DOI: 10.1016/j.gaitpost.2022.09.082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 07/12/2022] [Accepted: 09/19/2022] [Indexed: 02/02/2023]
Abstract
BACKGROUND Robotic exoskeletons have been developed to assist locomotion and address gait abnormalities in children with cerebral palsy (CP). These wearable assistive devices provide powered assistance to the lower-extremity joints, as well as support and stability. RESEARCH QUESTION Does exoskeleton-assisted walking improve gait in children with CP? METHODS The PRISMA guidelines were used to conduct this systematic review. Articles were obtained in a search of the following electronic databases: Embase, CINAHL Complete, PubMed, Web of Science and MEDLINE. Studies investigating spatiotemporal, kinematic, kinetic, muscle activity and/or physiological parameters during exoskeleton-assisted walking in children with CP were included. All articles were assessed for methodological quality using an adapted version of the Quality Assessment Tool for Before-After (Pre-Post) Studies with No Control Group, provided by the National Institutes of Health (NIH). RESULTS Thirteen studies were included. They involved the use of the following exoskeletons: tethered knee exoskeleton, pediatric knee exoskeleton (P.REX), untethered ankle exoskeleton, WAKE-Up ankle module, WAKE-Up ankle & knee module and unilateral ankle exosuit. Methodological quality varied, with key limitations in sample size and allocated time to adapt to the exoskeleton. There was a consensus that robotic exoskeletons improve gait given careful optimisation of exoskeleton torque and sufficient exoskeleton practice time for each participant. Improvements in gait included reduced metabolic cost of walking, increased walking speed, and increased knee and hip extension during stance. Furthermore, exoskeletons with an actuated ankle module were shown to promote normal ankle rocker function. SIGNIFICANCE Robotic exoskeletons have the potential to improve the mobility of CP children and may therefore increase community participation and improve quality of life. Future work should involve larger controlled intervention studies utilising robotic exoskeletons to improve gait in children with CP. These studies should ensure sufficient exoskeleton practice time for each participant.
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Affiliation(s)
- Markus Hunt
- Section of Sport, Exercise and Rehabilitation Science, School of Psychology and Life Sciences, Canterbury Christ Church University, North Holmes Road Campus, Canterbury, Kent CT1 1QU, UK.
| | - Laure Everaert
- Clinical Motion Analysis Laboratory, University Hospital Leuven, Weligerveld 1, 3212 Pellenberg, Belgium; Department of Rehabilitation Sciences, Research Group for Neurorehabilitation (eNRGy), KU Leuven, Tervuursevest 101, 3001 Leuven, Belgium.
| | - Mathew Brown
- Section of Sport, Exercise and Rehabilitation Science, School of Psychology and Life Sciences, Canterbury Christ Church University, North Holmes Road Campus, Canterbury, Kent CT1 1QU, UK.
| | - Luiza Muraru
- Mobilab & Care, Thomas More University of Applied Sciences, Kleinhoefstraat 4, Geel, Belgium.
| | - Eleni Hatzidimitriadou
- Faculty of Medicine, Health and Social Care, Canterbury Christ Church University, North Holmes Road Campus, Canterbury, Kent CT1 1QU, UK.
| | - Kaat Desloovere
- Clinical Motion Analysis Laboratory, University Hospital Leuven, Weligerveld 1, 3212 Pellenberg, Belgium; Department of Rehabilitation Sciences, Research Group for Neurorehabilitation (eNRGy), KU Leuven, Tervuursevest 101, 3001 Leuven, Belgium.
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18
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Conner BC, Spomer AM, Bishe SSPA, Steele KM, Lerner ZF. Soleus H-reflex modulation in cerebral palsy and its relationship with neural control complexity: a pilot study. Exp Brain Res 2022; 240:2073-2084. [PMID: 35752662 PMCID: PMC10072969 DOI: 10.1007/s00221-022-06399-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 06/09/2022] [Indexed: 02/08/2023]
Abstract
Individuals with cerebral palsy (CP) display motor control patterns that suggest decreased supraspinal input, but it remains unknown if they are able to modulate lower-limb reflexes in response to more complex tasks, or whether global motor control patterns relate to reflex modulation capacity in this population. Eight ambulatory individuals with CP (12-18 years old) were recruited to complete a task complexity protocol, where soleus H-reflex excitability was compared between bilateral (baseline) and unilateral (complex) standing. We also investigated the relationship between each participant's ability to modulate soleus H-reflex excitability and the complexity of their walking neural control pattern determined from muscle synergy analysis. Finally, six of the eight participants completed an exoskeleton walking protocol, where soleus H-reflexes were collected during the stance phase of walking with and without stance-phase plantar flexor resistance. Participants displayed a significant reduction in soleus H-reflex excitability (- 26 ± 25%, p = 0.04) with unilateral standing, and a strong positive relationship was observed between more refined neural control during walking and an increased ability to modulate reflex excitability (R = 0.79, p = 0.04). There was no difference in neuromuscular outcome measures with and without the ankle exoskeleton (p values all > 0.05), with variable reflex responses to walking with ankle exoskeleton resistance. These findings provide evidence that ambulatory individuals with CP retain some capacity to modulate lower-limb reflexes in response to increased task complexity, and that less refined neural control during walking appears to be related to deficits in reflex modulation.
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Affiliation(s)
- Benjamin C Conner
- College of Medicine, Phoenix, University of Arizona, Phoenix, AZ, USA
| | - Alyssa M Spomer
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA
| | - Safoura Sadegh Pour Aji Bishe
- Department of Mechanical Engineering, Northern Arizona University, 15600 S McConnell Drive, NAU EGRBldg 69, Flagstaff, AZ, 86011, USA
| | - Katherine M Steele
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA
| | - Zachary F Lerner
- College of Medicine, Phoenix, University of Arizona, Phoenix, AZ, USA. .,Department of Mechanical Engineering, Northern Arizona University, 15600 S McConnell Drive, NAU EGRBldg 69, Flagstaff, AZ, 86011, USA.
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19
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Bulea TC, Molazadeh V, Thurston M, Damiano DL. Interleaved Assistance and Resistance for Exoskeleton Mediated Gait Training: Validation, Feasibility and Effects. PROCEEDINGS OF THE ... IEEE/RAS-EMBS INTERNATIONAL CONFERENCE ON BIOMEDICAL ROBOTICS AND BIOMECHATRONICS. IEEE/RAS-EMBS INTERNATIONAL CONFERENCE ON BIOMEDICAL ROBOTICS AND BIOMECHATRONICS 2022; 2022:10.1109/biorob52689.2022.9925419. [PMID: 37650006 PMCID: PMC10466479 DOI: 10.1109/biorob52689.2022.9925419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Strength and selective motor control are primary determinants of pathological gait in children with cerebral palsy (CP) and other neuromotor disorders. Emerging evidence suggests robotic application of task-specific resistance to functional movements may provide the opportunity to strengthen muscles and improve neuromuscular function during walking in children with CP. Such a strategy could be most beneficial to children who are more severely affected by the pathology but their ability to overcome such resistance and maintain functional ambulation remains unclear. The goal of this study was to design, validate and evaluate initial feasibility and effects of a novel exoskeleton strategy that provides interleaved assistance and resistance to knee extension during overground walking. One participant with CP (GMFCS III) was recruited and completed ten total visits, nine walking with the exoskeleton. Our results validated the controller's ability to parse the gait cycle into five discrete phases (mean accuracy 91%) and provide knee extension assistance during stance and resistance during swing. Following acclimation to the interleaved strategy, peak knee extension was significantly improved in both the left (mean 7.9 deg) and right (15.2 deg) limbs when walking with the exoskeleton. Knee extensor EMG during late swing phase increased to 2.7 (left leg) and 1.7 (right leg) times the activation level during baseline exoskeleton walking without resistance. These results indicate that this interleaved strategy warrants further investigation in a longitudinal intervention study, particularly in individuals who may be more severely affected such that they are unable to ambulate overground using an exoskeleton training strategy that only deploys targeted resistance to limb motion.
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Affiliation(s)
- Thomas C Bulea
- Functional & Applied Biomechanics Section of the Rehabilitation Medicine Department at the National Institutes of Health Clinical Center, Bethesda, MD 20892 USA
| | - Vahidreza Molazadeh
- Functional & Applied Biomechanics Section of the Rehabilitation Medicine Department at the National Institutes of Health Clinical Center, Bethesda, MD 20892 USA
| | - Maxwell Thurston
- Functional & Applied Biomechanics Section of the Rehabilitation Medicine Department at the National Institutes of Health Clinical Center, Bethesda, MD 20892 USA
| | - Diane L Damiano
- Functional & Applied Biomechanics Section of the Rehabilitation Medicine Department at the National Institutes of Health Clinical Center, Bethesda, MD 20892 USA
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20
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Conner BC, Lerner ZF. Improving Ankle Muscle Recruitment via Plantar Pressure Biofeedback during Robot Resisted Gait Training in Cerebral Palsy. IEEE Int Conf Rehabil Robot 2022; 2022:1-6. [PMID: 36176108 DOI: 10.1109/icorr55369.2022.9896581] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Neurological impairment from stroke or cerebral palsy often presents with diminished ankle plantar flexor function during the propulsive phase of gait. This deficit often results in slow, energy-expensive walking patterns that limit community mobility. Robotic gait training interventions may prove effective in improving functional outcomes, including exoskeleton resistance used to provide targeted neuromuscular recruitment. However, these interventions to date have required regular verbal cues and coaching for proper plantar flexor engagement with resistance, particularly for pediatric applications. In this validation study, we sought to address the need for automating and improving the effectiveness of facilitating user engagement with robotic resistance. Specifically, our main goal was to compare changes in plantar flexor activity between walking with plantar flexor resistance alone vs plantar flexor resistance combined with plantar pressure biofeedback in individuals with cerebral palsy. We recruited 8 ambulatory adolescents with cerebral palsy between the ages of 11-18 years old to participate in this cross-sectional feasibility study. Supporting our hypothesis, we observed a 36 ± 36% and 46 ± 39% increase in mean and peak soleus activity, respectively, between resistance plus biofeedback vs resistance alone (both p < 0.05). Compared to other biofeedback sensing modalities like assessment of muscle activity via surface electrodes, integrating the plantar pressure-based system within the wearable robotic devices minimizes barriers to clinical implementation by reducing cost, complexity, and setup time. With these positive feasibility results, our future work will explore longer-term training effects of ankle resistance combined with plantar pressure biofeedback.
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21
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Smati S, Pouliot-Laforte A, Chevalier M, Lemay M, Ballaz L. Effect of power training on locomotion capacities in children with cerebral palsy with GMFCS level III-IV. Disabil Rehabil 2022:1-7. [PMID: 35737476 DOI: 10.1080/09638288.2022.2090623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
PURPOSE Power training (PT) is a promising training modality to improve functional abilities in children with cerebral palsy (CP). This study aimed to implement PT in an adapted school and to assess its effect on locomotion capacities in children with Gross Motor Function Classification System (GMFCS) level III-IV. MATERIALS AND METHODS Nine children with CP (GMFCS level III-IV) were trained three times/week for 12 weeks. The training sessions took place during the 50-minute physical activity classes and included high intensity exercise. The outcome measures were the performance on the 10-meter comfortable and fast walking tests, the 50-meter sprint test (50M-ST), and the energy expenditure index (EEI). RESULTS Participants spent 12 ± 7 and 7 ± 9 min per session at an intensity superior to 40% and 60% of the heart rate reserve, respectively. Performance in the 10-meter walking test (13.5 ± 7.8 to 9.9 ± 4.6 s, p < 0.05), the 10-meter fast walking test (8.8 ± 3.1 to 7.0 ± 3.2 s, p < 0.05), the 6-minute walking exercise (199.0 ± 48.6 to 316.6 ± 107.2 m, p < 0.05), and in 50M-ST (53.8 ± 29.5 to 42.3 ± 16.2 s, p < 0.05) increased after training. The EEI was reduced after training (p = 0.01), resulting in a more efficient gait. CONCLUSIONS PT was successfully implemented in children with CP with GMFCS level III-IV. Results suggest that PT increases walking capacities.Implications for rehabilitationPower training (PT) is feasible with children with bilateral cerebral palsy with GMFCS level III and IV.Physical education course in specialist school is a valuable environment to implement PT in children with poor gross motor function.Power training results in locomotion capacities improvement.
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Affiliation(s)
- Sofia Smati
- Department of Physical Activity Sciences, UQAM, Montreal, Canada.,Sainte-Justine UHC Research Center, Montreal, Canada
| | - Annie Pouliot-Laforte
- Department of Physical Activity Sciences, UQAM, Montreal, Canada.,Sainte-Justine UHC Research Center, Montreal, Canada
| | | | - Martin Lemay
- Department of Physical Activity Sciences, UQAM, Montreal, Canada.,Sainte-Justine UHC Research Center, Montreal, Canada.,Groupe de Recherche en Activité Physique Adaptée (GRAPA), Montreal, Canada
| | - Laurent Ballaz
- Department of Physical Activity Sciences, UQAM, Montreal, Canada.,Sainte-Justine UHC Research Center, Montreal, Canada.,Groupe de Recherche en Activité Physique Adaptée (GRAPA), Montreal, Canada
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22
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Lora-Millan JS, Moreno JC, Rocon E. Coordination Between Partial Robotic Exoskeletons and Human Gait: A Comprehensive Review on Control Strategies. Front Bioeng Biotechnol 2022; 10:842294. [PMID: 35694226 PMCID: PMC9174608 DOI: 10.3389/fbioe.2022.842294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 04/28/2022] [Indexed: 12/02/2022] Open
Abstract
Lower-limb robotic exoskeletons have become powerful tools to assist or rehabilitate the gait of subjects with impaired walking, even when they are designed to act only partially over the locomotor system, as in the case of unilateral or single-joint exoskeletons. These partial exoskeletons require a proper method to synchronize their assistive actions and ensure correct inter-joint coordination with the user’s gait. This review analyzes the state of the art of control strategies to coordinate the assistance provided by these partial devices with the actual gait of the wearers. We have analyzed and classified the different approaches independently of the hardware implementation, describing their basis and principles. We have also reviewed the experimental validations of these devices for impaired and unimpaired walking subjects to provide the reader with a clear view of their technology readiness level. Eventually, the current state of the art and necessary future steps in the field are summarized and discussed.
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Affiliation(s)
- Julio S. Lora-Millan
- Centre for Automation and Robotics, Consejo Superior de Investigaciones Científicas-Universidad Politécnica de Madrid, CSIC-UPM, Madrid, Spain
- Electronic Technology Department, Universidad Rey Juan Carlos, Madrid, Spain
| | - Juan C. Moreno
- Neural Rehabilitation Group, Cajal Institute, Spanish National Research Council (CSIC), Madrid, Spain
| | - E. Rocon
- Centre for Automation and Robotics, Consejo Superior de Investigaciones Científicas-Universidad Politécnica de Madrid, CSIC-UPM, Madrid, Spain
- *Correspondence: E. Rocon,
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23
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Washabaugh EP, Krishnan C. Functional resistance training methods for targeting patient-specific gait deficits: A review of devices and their effects on muscle activation, neural control, and gait mechanics. Clin Biomech (Bristol, Avon) 2022; 94:105629. [PMID: 35344781 DOI: 10.1016/j.clinbiomech.2022.105629] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 03/11/2022] [Accepted: 03/15/2022] [Indexed: 02/07/2023]
Abstract
BACKGROUND Injuries to the neuromusculoskeletal system often result in weakness and gait impairments. Functional resistance training during walking-where patients walk while a device increases loading on the leg-is an emerging approach to combat these symptoms. However, there are many methods that can be used to resist the patient, which may alter the biomechanics of the training. Thus, all methods may not address patient-specific deficits. METHODS We performed a comprehensive electronic database search to identify articles that acutely (i.e., after a single training session) examined how functional resistance training during walking alters muscle activation, gait biomechanics, and neural plasticity. Only articles that examined these effects during training or following the removal of resistance (i.e., aftereffects) were included. FINDINGS We found 41 studies that matched these criteria. Most studies (24) used passive devices (e.g., weighted cuffs or resistance bands) while the remainder used robotic devices. Devices varied on if they were wearable (14) or externally tethered, and the type of resistance they applied (i.e., inertial [14], elastic [8], viscous [7], or customized [12]). Notably, these methods provided device-specific changes in muscle activation, biomechanics, and spatiotemporal and kinematic aftereffects. Some evidence suggests this training results in task-specific increases in neural excitability. INTERPRETATION These findings suggest that careful selection of resistive strategies could help target patient-specific strength deficits and gait impairments. Also, many approaches are low-cost and feasible for clinical or in-home use. The results provide new insights for clinicians on selecting an appropriate functional resistance training strategy to target patient-specific needs.
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Affiliation(s)
- Edward P Washabaugh
- Department of Biomedical Engineering, Wayne State University, Detroit, MI, USA; Michigan Medicine Department of Physical Medicine and Rehabilitation, University of Michigan, Ann Arbor, MI, USA
| | - Chandramouli Krishnan
- Michigan Medicine Department of Physical Medicine and Rehabilitation, University of Michigan, Ann Arbor, MI, USA; Michigan Robotics, University of Michigan, Ann Arbor, MI, USA.
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Application of Wearable Sensors in Actuation and Control of Powered Ankle Exoskeletons: A Comprehensive Review. SENSORS 2022; 22:s22062244. [PMID: 35336413 PMCID: PMC8954890 DOI: 10.3390/s22062244] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 02/28/2022] [Accepted: 03/08/2022] [Indexed: 02/06/2023]
Abstract
Powered ankle exoskeletons (PAEs) are robotic devices developed for gait assistance, rehabilitation, and augmentation. To fulfil their purposes, PAEs vastly rely heavily on their sensor systems. Human–machine interface sensors collect the biomechanical signals from the human user to inform the higher level of the control hierarchy about the user’s locomotion intention and requirement, whereas machine–machine interface sensors monitor the output of the actuation unit to ensure precise tracking of the high-level control commands via the low-level control scheme. The current article aims to provide a comprehensive review of how wearable sensor technology has contributed to the actuation and control of the PAEs developed over the past two decades. The control schemes and actuation principles employed in the reviewed PAEs, as well as their interaction with the integrated sensor systems, are investigated in this review. Further, the role of wearable sensors in overcoming the main challenges in developing fully autonomous portable PAEs is discussed. Finally, a brief discussion on how the recent technology advancements in wearable sensors, including environment—machine interface sensors, could promote the future generation of fully autonomous portable PAEs is provided.
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Feasibility evaluation of a dual-mode ankle exoskeleton to assist and restore community ambulation in older adults. WEARABLE TECHNOLOGIES 2022; 3:E13. [PMID: 36404993 PMCID: PMC9673997 DOI: 10.1017/wtc.2022.12] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Background Age-related deficits in plantar flexor muscle function during the push-off phase of walking likely contribute to the decline in mobility that affects many older adults. Isolated strengthening of the plantar flexor muscles has failed to improve push-off power or walking economy in this population. New mobility aids and/or functional training interventions may help slow or prevent ambulatory decline in the elderly. Objective The overarching objective of this study was to explore the feasibility of using an untethered, dual-mode ankle exoskeleton for treating walking disability in the elderly; testing the device in assistance mode as a mobility aid to reduce energy consumption, and as a resistive gait training tool to facilitate functional recruitment of the plantar flexor muscles. Methods We recruited 6 older adults between the ages of 68 to 83 years to evaluate the feasibility of the dual-mode exoskeleton across two visits. On the first visit, we quantified acute metabolic and neuromuscular adaption to ankle exoskeleton assistance during walking in older adults, and subsequently determined if higher baseline energy cost was related to an individual's potential to benefit from untethered assistance. On the second visit, we validated the potential for push-off phase ankle resistance combined with plantar pressure biofeedback to facilitate functional utilization of the ankle plantar flexors during walking. We also conducted a twelve-session ankle resistance training protocol with one pilot participant to explore the effects of gait training with wearable ankle resistance on mobility and plantar flexor strength. Results Participants reached the lowest net metabolic power, soleus variance ratio, and soleus iEMG at 6.6 ± 1.6, 19.8 ± 1.6, and 5.8 ± 4.9 minutes, respectively, during the 30-minute exoskeleton assistance adaptation trial. Four of five participants exhibited a reduction (up to 19%) in metabolic power during walking with assistance relative to baseline, but there was no group-level change. Participants who had greater baseline metabolic power exhibited a greater reduction during walking with assistance. Walking with resistance increased stance-phase soleus iEMG by 18 - 186% and stance-phase average positive ankle power by 9 - 88% compared to baseline. Following ankle resistance gait training, the participant exhibited a 5% increase in self-selected walking speed, a 15% increase in fast walking speed, a 36% increase in 6-min-walk-test distance, and a 31% increase in plantar flexor strength compared to pre-intervention measurements. Conclusions Our results suggest that dual-mode ankle exoskeletons appear highly applicable to treating plantar flexor dysfunction in the elderly, with assistance holding potential as a mobility aid and resistance holding potential as a functional gait training tool. We used an untethered design to maximize the relevance of this for informing the design of intervention studies that may take place at home and in the community to improve mobility and quality of life in older adults. Future studies with larger sample sizes are recommended to expand on the results of this feasibility investigation.
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Swaminathan K, Park S, Raza F, Porciuncula F, Lee S, Nuckols RW, Awad LN, Walsh CJ. Ankle resistance with a unilateral soft exosuit increases plantarflexor effort during pushoff in unimpaired individuals. J Neuroeng Rehabil 2021; 18:182. [PMID: 34961521 PMCID: PMC8711150 DOI: 10.1186/s12984-021-00966-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 12/01/2021] [Indexed: 11/10/2022] Open
Abstract
Background Ankle-targeting resistance training for improving plantarflexion function during walking increases rehabilitation intensity, an important factor for motor recovery after stroke. However, understanding of the effects of resisting plantarflexion during stance on joint kinetics and muscle activity—key outcomes in evaluating its potential value in rehabilitation—remains limited. This initial study uses a unilateral exosuit that resists plantarflexion during mid-late stance in unimpaired individuals to test the hypotheses that when plantarflexion is resisted, individuals would (1) increase plantarflexor ankle torque and muscle activity locally at the resisted ipsilateral ankle, but (2) at higher forces, exhibit a generalized response that also uses the unresisted joints and limb. Further, we expected (3) short-term retention into gait immediately after removal of resistance. Methods Ten healthy young adults walked at 1.25 m s−1 for four 10-min discrete bouts, each comprising baseline, exposure to active exosuit-applied resistance, and post-active sections. In each bout, a different force magnitude was applied based on individual baseline ankle torques. The peak resistance torque applied by the exosuit was 0.13 ± 0.01, 0.19 ± 0.01, 0.26 ± 0.02, and 0.32 ± 0.02 N m kg−1, in the LOW, MED, HIGH, and MAX bouts, respectively. Results (1) Across all bouts, participants increased peak ipsilateral biological ankle torque by 0.13–0.25 N m kg−1 (p < 0.001) during exosuit-applied resistance compared to corresponding baselines. Additionally, ipsilateral soleus activity during stance increased by 5.4–11.3% (p < 0.05) in all but the LOW bout. (2) In the HIGH and MAX bouts, vertical ground reaction force decreased on the ipsilateral limb while increasing on the contralateral limb (p < 0.01). Secondary analysis found that the force magnitude that maximized increases in biological ankle torque without significant changes in limb loading varied by subject. (3) Finally, peak ipsilateral plantarflexion angle increased significantly during post-exposure in the intermediate HIGH resistance bout (p < 0.05), which corresponded to the greatest average increase in soleus activity (p > 0.10). Conclusions Targeted resistance of ankle plantarflexion during stance by an exosuit consistently increased local ipsilateral plantarflexor effort during active resistance, but force magnitude will be an important parameter to tune for minimizing the involvement of the unresisted joints and limb during training. Supplementary Information The online version contains supplementary material available at 10.1186/s12984-021-00966-5.
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Affiliation(s)
- Krithika Swaminathan
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA, 02134, USA
| | - Sungwoo Park
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA, 02134, USA
| | - Fouzia Raza
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA, 02134, USA
| | - Franchino Porciuncula
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA, 02134, USA.,Sargent College of Health and Rehabilitation Science, Boston University, Boston, MA, 02215, USA
| | - Sangjun Lee
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA, 02134, USA
| | - Richard W Nuckols
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA, 02134, USA
| | - Louis N Awad
- Sargent College of Health and Rehabilitation Science, Boston University, Boston, MA, 02215, USA
| | - Conor J Walsh
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Boston, MA, 02134, USA.
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Sarajchi M, Al-Hares MK, Sirlantzis K. Wearable Lower-Limb Exoskeleton for Children With Cerebral Palsy: A Systematic Review of Mechanical Design, Actuation Type, Control Strategy, and Clinical Evaluation. IEEE Trans Neural Syst Rehabil Eng 2021; 29:2695-2720. [PMID: 34910636 DOI: 10.1109/tnsre.2021.3136088] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Children with a neurological disorder such as cerebral palsy (CP) severely suffer from a reduced quality of life because of decreasing independence and mobility. Although there is no cure yet, a lower-limb exoskeleton (LLE) has considerable potential to help these children experience better mobility during overground walking. The research in wearable exoskeletons for children with CP is still at an early stage. This paper shows that the number of published papers on LLEs assisting children with CP has significantly increased in recent years; however, no research has been carried out to review these studies systematically. To fill up this research gap, a systematic review from a technical and clinical perspective has been conducted, based on the PRISMA guidelines, under three extended topics associated with "lower limb", "exoskeleton", and "cerebral palsy" in the databases Scopus and Web of Science. After applying several exclusion criteria, seventeen articles focused on fifteen LLEs were included for careful consideration. These studies address some consistent positive evidence on the efficacy of LLEs in improving gait patterns in children with CP. Statistical findings show that knee exoskeletons, brushless DC motors, the hierarchy control architecture, and CP children with spastic diplegia are, respectively, the most common mechanical design, actuator type, control strategy, and clinical characteristics for these LLEs. Clinical studies suggest ankle-foot orthosis as the primary medical solution for most CP gait patterns; nevertheless, only one motorized ankle exoskeleton has been developed. This paper shows that more research and contribution are needed to deal with open challenges in these LLEs.
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Gonzalez A, Garcia L, Kilby J, McNair P. Robotic devices for paediatric rehabilitation: a review of design features. Biomed Eng Online 2021; 20:89. [PMID: 34488777 PMCID: PMC8420060 DOI: 10.1186/s12938-021-00920-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 08/06/2021] [Indexed: 01/11/2023] Open
Abstract
Children with physical disabilities often have limited performance in daily activities, hindering their physical development, social development and mental health. Therefore, rehabilitation is essential to mitigate the adverse effects of the different causes of physical disabilities and improve independence and quality of life. In the last decade, robotic rehabilitation has shown the potential to augment traditional physical rehabilitation. However, to date, most robotic rehabilitation devices are designed for adult patients who differ in their needs compared to paediatric patients, limiting the devices' potential because the paediatric patients' needs are not adequately considered. With this in mind, the current work reviews the existing literature on robotic rehabilitation for children with physical disabilities, intending to summarise how the rehabilitation robots could fulfil children's needs and inspire researchers to develop new devices. A literature search was conducted utilising the Web of Science, PubMed and Scopus databases. Based on the inclusion-exclusion criteria, 206 publications were included, and 58 robotic devices used by children with a physical disability were identified. Different design factors and the treated conditions using robotic technology were compared. Through the analyses, it was identified that weight, safety, operability and motivation were crucial factors to the successful design of devices for children. The majority of the current devices were used for lower limb rehabilitation. Neurological disorders, in particular cerebral palsy, were the most common conditions for which devices were designed. By far, the most common actuator was the electric motor. Usually, the devices present more than one training strategy being the assistive strategy the most used. The admittance/impedance method is the most popular to interface the robot with the children. Currently, there is a trend on developing exoskeletons, as they can assist children with daily life activities outside of the rehabilitation setting, propitiating a wider adoption of the technology. With this shift in focus, it appears likely that new technologies to actuate the system (e.g. serial elastic actuators) and to detect the intention (e.g. physiological signals) of children as they go about their daily activities will be required.
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Affiliation(s)
- Alberto Gonzalez
- BioDesign Lab, School of Engineering, Computer and Mathematical Sciences, Auckland University of Technology, Auckland, New Zealand
| | - Lorenzo Garcia
- BioDesign Lab, School of Engineering, Computer and Mathematical Sciences, Auckland University of Technology, Auckland, New Zealand.
| | - Jeff Kilby
- BioDesign Lab, School of Engineering, Computer and Mathematical Sciences, Auckland University of Technology, Auckland, New Zealand
| | - Peter McNair
- Health and Rehabilitation Research Institute, Auckland University of Technology, Auckland, New Zealand
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Conner BC, Schwartz MH, Lerner ZF. Pilot evaluation of changes in motor control after wearable robotic resistance training in children with cerebral palsy. J Biomech 2021; 126:110601. [PMID: 34332214 DOI: 10.1016/j.jbiomech.2021.110601] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 03/12/2021] [Accepted: 06/24/2021] [Indexed: 10/20/2022]
Abstract
Cerebral palsy (CP) is characterized by deficits in motor function due to reduced neuromuscular control. We leveraged the guiding principles of motor learning theory to design a wearable robotic intervention intended to improve neuromuscular control of the ankle. The goal of this study was to determine the neuromuscular and biomechanical response to four weeks of exoskeleton ankle resistance therapy (exo-therapy) in children with CP. Five children with CP (12 - 17 years, GMFCS I - II, two diplegic and three hemiplegic, four males and one female) were recruited for ten 20-minute sessions of exo-therapy. Surface electromyography, three-dimensional kinematics, and metabolic data were collected at baseline and after training was complete. After completion of training and with no device on, participants walked with decreased co-contraction between the plantar flexors and dorsiflexors (-29 ± 11%, p = 0.02), a more typical plantar flexor activation profile (33 ± 13% stronger correlation to a typical soleus activation profile, p = 0.01), and increased neural control complexity (7 ± 3%, p < 0.01 measured via muscle synergy analysis). These improvements in neuromuscular control led to a more mechanically efficient gait pattern (58 ± 34%, p < 0.05) with a reduced metabolic cost of transport (-29 ± 15%, p = 0.02). The findings from this study suggest that ankle exoskeleton resistance therapy shows promise for rapidly improving neuromuscular control for children with CP, and may serve as a meaningful rehabilitative complement to common surgical procedures.
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Affiliation(s)
- Benjamin C Conner
- College of Medicine - Phoenix, University of Arizona, Phoenix, AZ, USA
| | - Michael H Schwartz
- James R. Gage Center for Gait & Motion Analysis, Gillette Children's Specialty Healthcare, St. Paul, MN, USA; Department of Orthopaedic Surgery, University of Minnesota, Minneapolis, MN, USA
| | - Zachary F Lerner
- College of Medicine - Phoenix, University of Arizona, Phoenix, AZ, USA; Department of Mechanical Engineering, Northern Arizona University, Flagstaff, AZ, USA.
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Washabaugh EP, Augenstein TE, Ebenhoeh AM, Qiu J, Ford KA, Krishnan C. Design and Preliminary Assessment of a Passive Elastic Leg Exoskeleton for Resistive Gait Rehabilitation. IEEE Trans Biomed Eng 2020; 68:1941-1950. [PMID: 33201805 DOI: 10.1109/tbme.2020.3038582] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
OBJECTIVE This article aimed to develop a unique exoskeleton to provide different types of elastic resistances (i.e., resisting flexion, extension, or bidirectionally) to the leg muscles during walking. METHODS We created a completely passive leg exoskeleton, consisting of counteracting springs, pulleys, and clutches, to provide different types of elastic resistance to the knee. We first used a benchtop setting to calibrate the springs and validate the resistive capabilities of the device. We then tested the device's ability to alter gait mechanics, muscle activation, and kinematic aftereffects when walking on a treadmill under the three resistance types. RESULTS Benchtop testing indicated that the device provided a nearly linear torque profile and could be accurately configured to alter the angle where the spring system was undeformed (i.e., the resting position). Treadmill testing indicated the device could specifically target knee flexors, extensors, or both, and increase eccentric loading at the joint. Additionally, these resistance types elicited different kinematic aftereffects that could be used to target user-specific spatiotemporal gait deficits. CONCLUSION These results indicate that the elastic device can provide various types of targeted resistance training during walking. SIGNIFICANCE The proposed elastic device can provide a diverse set of resistance types that could potentially address user-specific muscle weaknesses and gait deficits through functional resistance training.
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Conner BC, Remec NM, Orum EK, Frank EM, Lerner ZF. Wearable Adaptive Resistance Training Improves Ankle Strength, Walking Efficiency and Mobility in Cerebral Palsy: A Pilot Clinical Trial. IEEE OPEN JOURNAL OF ENGINEERING IN MEDICINE AND BIOLOGY 2020; 1:282-289. [PMID: 33251524 PMCID: PMC7694567 DOI: 10.1109/ojemb.2020.3035316] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 10/23/2020] [Accepted: 10/27/2020] [Indexed: 11/07/2022] Open
Abstract
GOAL To determine the efficacy of wearable adaptive resistance training for rapidly improving walking ability in children with cerebral palsy (CP). METHODS Six children with spastic CP (five males, one female; mean age 14y 11mo; three hemiplegic, three diplegic; Gross Motor Function Classification System [GMFCS] levels I and II) underwent ten, 20-minute training sessions over four weeks with a wearable adaptive resistance device. Strength, speed, walking efficiency, timed up and go (TUG), and six-minute walk test (6MWT) were used to measure training outcomes. RESULTS Participants showed increased average plantar flexor strength (17 ± 8%, p = 0.02), increased preferred walking speed on the treadmill (39 ± 25%, p = 0.04), improved metabolic cost of transport (33 ± 9%, p = 0.03), and enhanced performance on the timed up and go (11 ± 9%, p = 0.04) and six-minute walk test (13 ± 9%, p = 0.04). CONCLUSIONS The observed increase in preferred walking speed, reduction in metabolic cost of transport, and improved performance on clinical tests of mobility highlights the potentially transformative nature of this novel therapy; the rate at which this intervention elicited improved function was 3 - 6 times greater than what has been reported previously.
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Affiliation(s)
| | | | | | - Emily M. Frank
- College of Health SolutionsArizona State UniversityTempeAZ85281USA
| | - Zachary F. Lerner
- Mechanical Engineering DepartmentNorthern Arizona UniversityFlagstaffAZ86011USA
- Department of OrthopedicsUniversity of Arizona College of Medicine – PhoenixPhoenixAZ85004USA
- Department of Mechanical EngineeringNorthern Arizona UniversityFlagstaffAZ86011USA
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