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Becerra-Fajardo L, Minguillon J, Krob MO, Rodrigues C, González-Sánchez M, Megía-García Á, Galán CR, Henares FG, Comerma A, Del-Ama AJ, Gil-Agudo A, Grandas F, Schneider-Ickert A, Barroso FO, Ivorra A. First-in-human demonstration of floating EMG sensors and stimulators wirelessly powered and operated by volume conduction. J Neuroeng Rehabil 2024; 21:4. [PMID: 38172975 PMCID: PMC10765656 DOI: 10.1186/s12984-023-01295-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 12/12/2023] [Indexed: 01/05/2024] Open
Abstract
BACKGROUND Recently we reported the design and evaluation of floating semi-implantable devices that receive power from and bidirectionally communicate with an external system using coupling by volume conduction. The approach, of which the semi-implantable devices are proof-of-concept prototypes, may overcome some limitations presented by existing neuroprostheses, especially those related to implant size and deployment, as the implants avoid bulky components and can be developed as threadlike devices. Here, it is reported the first-in-human acute demonstration of these devices for electromyography (EMG) sensing and electrical stimulation. METHODS A proof-of-concept device, consisting of implantable thin-film electrodes and a nonimplantable miniature electronic circuit connected to them, was deployed in the upper or lower limb of six healthy participants. Two external electrodes were strapped around the limb and were connected to the external system which delivered high frequency current bursts. Within these bursts, 13 commands were modulated to communicate with the implant. RESULTS Four devices were deployed in the biceps brachii and the gastrocnemius medialis muscles, and the external system was able to power and communicate with them. Limitations regarding insertion and communication speed are reported. Sensing and stimulation parameters were configured from the external system. In one participant, electrical stimulation and EMG acquisition assays were performed, demonstrating the feasibility of the approach to power and communicate with the floating device. CONCLUSIONS This is the first-in-human demonstration of EMG sensors and electrical stimulators powered and operated by volume conduction. These proof-of-concept devices can be miniaturized using current microelectronic technologies, enabling fully implantable networked neuroprosthetics.
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Affiliation(s)
- Laura Becerra-Fajardo
- Department of Information and Communications Technologies, Universitat Pompeu Fabra, Barcelona, 08018, Spain
| | - Jesus Minguillon
- Department of Information and Communications Technologies, Universitat Pompeu Fabra, Barcelona, 08018, Spain
- Research Centre for Information and Communications Technologies, University of Granada, Granada, 18014, Spain
- Department of Signal Theory, Telematics and Communications, University of Granada, Granada, 18014, Spain
| | - Marc Oliver Krob
- Fraunhofer Institute for Biomedical Engineering IBMT, 66280, Sulzbach, Germany
| | - Camila Rodrigues
- Neural Rehabilitation Group, Cajal Institute, Spanish National Research Council (CSIC), Madrid, 28002, Spain
- Systems Engineering and Automation Department, Carlos III University of Madrid, Madrid, 28903, Spain
| | - Miguel González-Sánchez
- Movement Disorders Unit, Department of Neurology, Hospital General Universitario Gregorio Marañón, Madrid, 28007, Spain
| | - Álvaro Megía-García
- Biomechanics and Assistive Technology Unit, National Hospital for Paraplegics. Unit of Neurorehabilitation, Biomechanics and Sensory-Motor Function (HNP-SESCAM), Unit associated to the CSIC, Toledo, Spain
| | - Carolina Redondo Galán
- Biomechanics and Assistive Technology Unit, National Hospital for Paraplegics. Unit of Neurorehabilitation, Biomechanics and Sensory-Motor Function (HNP-SESCAM), Unit associated to the CSIC, Toledo, Spain
| | - Francisco Gutiérrez Henares
- Biomechanics and Assistive Technology Unit, National Hospital for Paraplegics. Unit of Neurorehabilitation, Biomechanics and Sensory-Motor Function (HNP-SESCAM), Unit associated to the CSIC, Toledo, Spain
| | - Albert Comerma
- Department of Information and Communications Technologies, Universitat Pompeu Fabra, Barcelona, 08018, Spain
| | - Antonio J Del-Ama
- School of Science and Technology, Department of Applied Mathematics, Materials Science and Engineering and Electronic Technology, Rey Juan Carlos University, Móstoles, 28933, Spain
| | - Angel Gil-Agudo
- Biomechanics and Assistive Technology Unit, National Hospital for Paraplegics. Unit of Neurorehabilitation, Biomechanics and Sensory-Motor Function (HNP-SESCAM), Unit associated to the CSIC, Toledo, Spain
- CSIC's Associated RDI Unit 'Unidad De Neurorehabilitación, Biomecánica Y Función Sensitivo-Motora', Madrid, Spain
| | - Francisco Grandas
- Movement Disorders Unit, Department of Neurology, Hospital General Universitario Gregorio Marañón, Madrid, 28007, Spain
| | | | - Filipe Oliveira Barroso
- Neural Rehabilitation Group, Cajal Institute, Spanish National Research Council (CSIC), Madrid, 28002, Spain
- CSIC's Associated RDI Unit 'Unidad De Neurorehabilitación, Biomecánica Y Función Sensitivo-Motora', Madrid, Spain
| | - Antoni Ivorra
- Department of Information and Communications Technologies, Universitat Pompeu Fabra, Barcelona, 08018, Spain.
- Serra Húnter Fellow Programme, Universitat Pompeu Fabra, Barcelona, 08018, Spain.
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Becerra-Fajardo L, Krob MO, Minguillon J, Rodrigues C, Welsch C, Tudela-Pi M, Comerma A, Oliveira Barroso F, Schneider A, Ivorra A. Floating EMG sensors and stimulators wirelessly powered and operated by volume conduction for networked neuroprosthetics. J Neuroeng Rehabil 2022; 19:57. [PMID: 35672857 PMCID: PMC9171952 DOI: 10.1186/s12984-022-01033-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 05/19/2022] [Indexed: 11/10/2022] Open
Abstract
Background Implantable neuroprostheses consisting of a central electronic unit wired to electrodes benefit thousands of patients worldwide. However, they present limitations that restrict their use. Those limitations, which are more adverse in motor neuroprostheses, mostly arise from their bulkiness and the need to perform complex surgical implantation procedures. Alternatively, it has been proposed the development of distributed networks of intramuscular wireless microsensors and microstimulators that communicate with external systems for analyzing neuromuscular activity and performing stimulation or controlling external devices. This paradigm requires the development of miniaturized implants that can be wirelessly powered and operated by an external system. To accomplish this, we propose a wireless power transfer (WPT) and communications approach based on volume conduction of innocuous high frequency (HF) current bursts. The currents are applied through external textile electrodes and are collected by the wireless devices through two electrodes for powering and bidirectional digital communications. As these devices do not require bulky components for obtaining power, they may have a flexible threadlike conformation, facilitating deep implantation by injection. Methods We report the design and evaluation of advanced prototypes based on the above approach. The system consists of an external unit, floating semi-implantable devices for sensing and stimulation, and a bidirectional communications protocol. The devices are intended for their future use in acute human trials to demonstrate the distributed paradigm. The technology is assayed in vitro using an agar phantom, and in vivo in hindlimbs of anesthetized rabbits. Results The semi-implantable devices were able to power and bidirectionally communicate with the external unit. Using 13 commands modulated in innocuous 3 MHz HF current bursts, the external unit configured the sensing and stimulation parameters, and controlled their execution. Raw EMG was successfully acquired by the wireless devices at 1 ksps. Conclusions The demonstrated approach overcomes key limitations of existing neuroprostheses, paving the way to the development of distributed flexible threadlike sensors and stimulators. To the best of our knowledge, these devices are the first based on WPT by volume conduction that can work as EMG sensors and as electrical stimulators in a network of wireless devices. Supplementary Information The online version contains supplementary material available at 10.1186/s12984-022-01033-3.
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