Real-time locomotion mode detection in individuals with transfemoral amputation and osseointegration

Abstract Background Despite notable advancements in prosthetic leg technology, commercially available devices with embedded algorithms utilizing bioelectric signals for prosthetic leg control are lacking. This untapped potential could enhance current prosthetic leg capabilities, enabling more natura...

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Main Authors: Bahareh Ahkami, Morten B. Kristoffersen, Max Ortiz-Catalan
Format: Article
Language:English
Published: BMC 2025-06-01
Series:Journal of NeuroEngineering and Rehabilitation
Subjects:
Online Access:https://doi.org/10.1186/s12984-025-01672-2
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author Bahareh Ahkami
Morten B. Kristoffersen
Max Ortiz-Catalan
author_facet Bahareh Ahkami
Morten B. Kristoffersen
Max Ortiz-Catalan
author_sort Bahareh Ahkami
collection DOAJ
description Abstract Background Despite notable advancements in prosthetic leg technology, commercially available devices with embedded algorithms utilizing bioelectric signals for prosthetic leg control are lacking. This untapped potential could enhance current prosthetic leg capabilities, enabling more natural movements. However, individuals with short residual limbs have limited available muscle and it has not been investigated if different locomotion modes can be predicted in real-time in this population. Here, we explored the feasibility of using electromyographic signals in individuals with short residual limbs and osseointegrated implants to infer locomotion modes. Methods We recorded data from five participants with transfemoral amputation and osseointegration while walking on level ground, stairs, and ramps. Electromyography, acceleration, angular velocity, and ground reaction force were collected using wireless sensors. Two sessions of recordings for offline and real-time evaluation were conducted, with 30 rounds and 15 rounds, respectively. Decoding was performed using a mode-specific, phase-dependent classifier. The method was implemented in LocoD, an existing open-source platform, allowing for further development by the community and allowing easy comparison between different classification algorithms. The evaluation of the platform and prediction algorithm relies on quantifying the transition error, signifying instances where the algorithm falls short in predicting shifts between different walking surfaces. Results In this study, a participant exhibited an average error as low as 1.2%, indicating precise predictions. Conversely, the highest average error was found at 23% in a different participant. This variation could be the result of factors related to the amputation such as residual limb length, remaining muscles, and the surgical technique used while performing the amputation, as well as differences in performing the movements. On average, offline classification resulted in a mean error of 5.7%, while the corresponding mean error during online (real-time) evaluation was 11.6%. Conclusion Our findings suggest that myoelectric signals can be potentially used in the control of prosthetic legs for individuals with short residual limbs with osseointegrated implants. Further research into understanding and compensating for variations in the locomotion detection accuracy for different participants is crucial.
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spelling doaj-art-5fe255c0c62e43e091bf49056cd00bdf2025-08-20T03:24:26ZengBMCJournal of NeuroEngineering and Rehabilitation1743-00032025-06-0122111510.1186/s12984-025-01672-2Real-time locomotion mode detection in individuals with transfemoral amputation and osseointegrationBahareh Ahkami0Morten B. Kristoffersen1Max Ortiz-Catalan2Center for Bionics and Pain ResearchCenter for Bionics and Pain ResearchCenter for Bionics and Pain ResearchAbstract Background Despite notable advancements in prosthetic leg technology, commercially available devices with embedded algorithms utilizing bioelectric signals for prosthetic leg control are lacking. This untapped potential could enhance current prosthetic leg capabilities, enabling more natural movements. However, individuals with short residual limbs have limited available muscle and it has not been investigated if different locomotion modes can be predicted in real-time in this population. Here, we explored the feasibility of using electromyographic signals in individuals with short residual limbs and osseointegrated implants to infer locomotion modes. Methods We recorded data from five participants with transfemoral amputation and osseointegration while walking on level ground, stairs, and ramps. Electromyography, acceleration, angular velocity, and ground reaction force were collected using wireless sensors. Two sessions of recordings for offline and real-time evaluation were conducted, with 30 rounds and 15 rounds, respectively. Decoding was performed using a mode-specific, phase-dependent classifier. The method was implemented in LocoD, an existing open-source platform, allowing for further development by the community and allowing easy comparison between different classification algorithms. The evaluation of the platform and prediction algorithm relies on quantifying the transition error, signifying instances where the algorithm falls short in predicting shifts between different walking surfaces. Results In this study, a participant exhibited an average error as low as 1.2%, indicating precise predictions. Conversely, the highest average error was found at 23% in a different participant. This variation could be the result of factors related to the amputation such as residual limb length, remaining muscles, and the surgical technique used while performing the amputation, as well as differences in performing the movements. On average, offline classification resulted in a mean error of 5.7%, while the corresponding mean error during online (real-time) evaluation was 11.6%. Conclusion Our findings suggest that myoelectric signals can be potentially used in the control of prosthetic legs for individuals with short residual limbs with osseointegrated implants. Further research into understanding and compensating for variations in the locomotion detection accuracy for different participants is crucial.https://doi.org/10.1186/s12984-025-01672-2ElectromyographyMyoelectric pattern recognitionLower limb prosthesesProstheticsOsseointegration
spellingShingle Bahareh Ahkami
Morten B. Kristoffersen
Max Ortiz-Catalan
Real-time locomotion mode detection in individuals with transfemoral amputation and osseointegration
Journal of NeuroEngineering and Rehabilitation
Electromyography
Myoelectric pattern recognition
Lower limb prostheses
Prosthetics
Osseointegration
title Real-time locomotion mode detection in individuals with transfemoral amputation and osseointegration
title_full Real-time locomotion mode detection in individuals with transfemoral amputation and osseointegration
title_fullStr Real-time locomotion mode detection in individuals with transfemoral amputation and osseointegration
title_full_unstemmed Real-time locomotion mode detection in individuals with transfemoral amputation and osseointegration
title_short Real-time locomotion mode detection in individuals with transfemoral amputation and osseointegration
title_sort real time locomotion mode detection in individuals with transfemoral amputation and osseointegration
topic Electromyography
Myoelectric pattern recognition
Lower limb prostheses
Prosthetics
Osseointegration
url https://doi.org/10.1186/s12984-025-01672-2
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AT mortenbkristoffersen realtimelocomotionmodedetectioninindividualswithtransfemoralamputationandosseointegration
AT maxortizcatalan realtimelocomotionmodedetectioninindividualswithtransfemoralamputationandosseointegration