Interleaved Assistance and Resistance for Exoskeleton Mediated Gait Training: Validation, Feasibility and Effects

Bulea, Thomas C.; Molazadeh, Vahidreza; Thurston, Maxwell; Damiano, Diane L.

doi:10.1109/biorob52689.2022.9925419

Cited by 3 publications

(8 citation statements)

References 35 publications

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“…Following these initial findings, a new, novel wearable robotic exoskeleton (NIH-Agilik) was developed with an expanded target population to include children with cerebral palsy, spina bifida, muscular dystrophy or incomplete spinal cord injury [ 36 ]. This device had a slimmer profile, was more power efficient, and incorporated a user-friendly interface to control the device settings, offering the potential to be applied outside of the clinical setting after initial safety and feasibility testing.…”

Section: Introductionmentioning

confidence: 99%

“…The NIH-Agilik is capable of applying torque bidirectionally (i.e., extensor or flexor) to assist or resist knee movement. Torque profiles, which are defined by specifying the torque magnitude and direction and the ramp on and ramp off rate, can be independently set for five phases of the gait cycle: early, mid- and late stance and early and late swing phase, enabling the overall torque profile during the stride to be tailored to each individual user [ 36 ]. This capability broadens the exoskeleton’s use-case by providing a tool to leverage the benefits of strength training with the possibility to improve selective motor control by delivering precisely targeted resistance to challenge functional movement.…”

Section: Introductionmentioning

confidence: 99%

“…We piloted an interleaved strategy with the NIH-Agilik exoskeleton that applied resistance to knee extension during late swing phase, which must be overcome by the user to complete each step, while also applying assistance to knee extension during early and mid-stance phase to provide antigravity support and maintain forward momentum [ 36 ]. This approach pursues the complementary goals of knee extensor strengthening to address the lower limb weakness and improved selective motor control by providing on-demand resistance during phases of active knee extension, while also leveraging the assistive torques to increase training duration.…”

Section: Introductionmentioning

confidence: 99%

“…This approach pursues the complementary goals of knee extensor strengthening to address the lower limb weakness and improved selective motor control by providing on-demand resistance during phases of active knee extension, while also leveraging the assistive torques to increase training duration. The immediate effects of this interleaved assistance and resistance control strategy on the biomechanics and neuromuscular activity of a single subject with cerebral palsy (GMFCS level III) were recently tested to establish initial feasibility of this strategy [ 36 ]. The control system displayed a high level of accuracy in providing appropriately timed torque to assist and resist knee extension during overground walking, resulting in immediate improvement in knee extension and simultaneous increase in knee extensor muscle activation, demonstrating the potential for strengthening after prolonged use [ 36 ].…”

Section: Introductionmentioning

confidence: 99%

“…The immediate effects of this interleaved assistance and resistance control strategy on the biomechanics and neuromuscular activity of a single subject with cerebral palsy (GMFCS level III) were recently tested to establish initial feasibility of this strategy [ 36 ]. The control system displayed a high level of accuracy in providing appropriately timed torque to assist and resist knee extension during overground walking, resulting in immediate improvement in knee extension and simultaneous increase in knee extensor muscle activation, demonstrating the potential for strengthening after prolonged use [ 36 ].…”

Section: Introductionmentioning

confidence: 99%

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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

Devine,

Alter,

Damiano

et al. 2024

PLoS ONE

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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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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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

Devine,

Alter,

Damiano

et al. 2024

PLoS ONE

View full text Add to dashboard Cite

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Attention-Based Deep Recurrent Neural Network to Estimate Knee Angle During Walking from Lower-Limb EMG

Abdelhady,

Damiano,

Bulea

2023

2023 International Conference on Rehabilitation Robotics (ICORR)

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Knee Angle Estimation from Surface EMG during Walking Using Attention-Based Deep Recurrent Neural Networks: Feasibility and Initial Demonstration in Cerebral Palsy

Abdelhady,

Damiano,

Bulea

2024

Sensors

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Accurately estimating knee joint angle during walking from surface electromyography (sEMG) signals can enable more natural control of wearable robotics like exoskeletons. However, challenges exist due to variability across individuals and sessions. This study evaluates an attention-based deep recurrent neural network combining gated recurrent units (GRUs) and an attention mechanism (AM) for knee angle estimation. Three experiments were conducted. First, the GRU-AM model was tested on four healthy adolescents, demonstrating improved estimation compared to GRU alone. A sensitivity analysis revealed that the key contributing muscles were the knee flexor and extensors, highlighting the ability of the AM to focus on the most salient inputs. Second, transfer learning was shown by pretraining the model on an open source dataset before additional training and testing on the four adolescents. Third, the model was progressively adapted over three sessions for one child with cerebral palsy (CP). The GRU-AM model demonstrated robust knee angle estimation across participants with healthy participants (mean RMSE 7 degrees) and participants with CP (RMSE 37 degrees). Further, estimation accuracy improved by 14 degrees on average across successive sessions of walking in the child with CP. These results demonstrate the feasibility of using attention-based deep networks for joint angle estimation in adolescents and clinical populations and support their further development for deployment in wearable robotics.

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Interleaved Assistance and Resistance for Exoskeleton Mediated Gait Training: Validation, Feasibility and Effects

Cited by 3 publications

References 35 publications

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

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

Attention-Based Deep Recurrent Neural Network to Estimate Knee Angle During Walking from Lower-Limb EMG

Knee Angle Estimation from Surface EMG during Walking Using Attention-Based Deep Recurrent Neural Networks: Feasibility and Initial Demonstration in Cerebral Palsy

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