A wireless fully implantable ECoG recording medical device WIMAGINE® for human Brain Computer Interface applications: toward a clinical trial
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1
CEA/LETI, MINATEC Campus, France
The WIMAGINE® implant was developed to record ECoG (ElectroCorticoGram) signals for long term clinical applications in the context of a Brain Computer Interface project which goal is to allow a tetraplegic subject to control a 4-limb exoskeleton thanks to his brain activity [1]. This active implantable medical device [2] is composed of an array of 64 biocompatible electrodes, a hermetic titanium housing including the electronic boards and biocompatible antennae for wireless transmission of data and remote power supply.
This implant is able to record ECoG on 64 electrodes with selectable gain and sampling frequency, with less than 0.7μV RMS input referred noise in the [0.5Hz – 300Hz] band thanks to a dedicated integrated circuit. It is powered remotely through an inductive link at 13.56MHz, communicates wirelessly on the MICS band at 402-405MHz with a custom designed base station connected to a PC and complies with the regulations applicable to class III AIMD. During the surgical procedure, the implant will be inserted into a 50 mm craniotomy so that the electrode array is in contact with the dura mater, and the implant recovered by the skin (Fig. 1).
The design of the WIMAGINE® implant takes into account all the constraints of long term implantable medical devices. In particular, WIMAGINE® was designed to satisfy the Essential requirements of the European Medical Device Directives 93/42/CEE and 90/385/EEC. A risk analysis according to ISO 14971 standards has been carried out, and risk management actions were set up. The implant manufacturing was achieved according to a qualified industrial process under ISO certification 13485. In order to increase the reliability, all electronic boards undergo a burn-in procedure to avoid early in-use system failures, and functional tests. The electronic board is encapsulated into a dedicated titanium packaging with hermetic feedthrough. The hermeticity is achieved by laser welding and tested in terms of helium leakage and yield 10-9 bar.cm-3.s-1. Then, each implant is tested, cleaned and sterilized according to a validated process. The mechanical and electrical qualification tests of the implant according to the ISO 45502-1 standards were successfully achieved by certified bodies, such as resistance to mechanical forces, vibrations and shocks, electrodes leakage current less than 1μA, heating at the surface of the implant less than 2°C. Likewise, the electrical security tests and electromagnetic compatibility (EMC) tests according to the EN 60601-1 were performed on the WIMAGINE® platform. Finally, the long-term biocompatibility is evaluating according to the ISO 10993.
The submission of the protocol for clinical trial authorization to the French authorities (ANSM and CPP) in the context of Brain Computer Interface for tetraplegia is in progress. Other neurological applications requiring wireless ECoG recording such as presurgical evaluation of epilepsy, or post stroke rehabilitation [3] can be addressed.
References
[1] A. Eliseyev, T. Aksenova, C. Mestais, A.-L. Benabid, et al., CLINATEC BCI platform based on the ECoG-recording implant WIMAGINE and the innovative signal-processing to control the exoskeleton EMY: preclinical results, EMBC, 36th Annual International Conference of the IEEE, 2014
[2] C. Mestais, G. Charvet, F. Sauter-Starace, M. Foerster, D. Ratel, and AL. Benabid, “WIMAGINE: Wireless 64-Channel ECoG Recording Implant for Long Term Clinical Applications”, IEEE Trans Neural Syst Rehabil Eng. 2015 Jan;23(1):10-21
[3] Silvoni, S., Ramos-Murguialday, A., Cavinato, M., Volpato, C., Cisotto, G., Turolla, A., ... & Birbaumer, N. (2011). Brain-computer interface in stroke: a review of progress. Clinical EEG and Neuroscience, 42(4), 245-252.
Acknowledgements
The development of WIMAGINE® Implant was supported by French National Research Agency (ANR-Carnot Institute), Fondation Motrice, Fondation Nanosciences, Fondation de l’Avenir, and Fondation Philanthropique Edmond J. Safra.
Keywords:
ECoG,
WIMAGINE,
Brain computer interface (BCI),
AIMD,
ANSM,
CPP
Conference:
2015 International Workshop on Clinical Brain-Machine Interfaces (CBMI2015), Tokyo, Japan, 13 Mar - 15 Mar, 2015.
Presentation Type:
Poster 3-2
Topic:
Clinical Brain-Machine Interfaces
Citation:
Charvet
G,
Mestais
C,
Sauter-Starace
F,
Foerster
M,
Lambert
A,
Chabrol
C,
Torres Martinez
NR,
Costecalde
T,
Ratel
D and
Benabid
AL
(2015). A wireless fully implantable ECoG recording medical device WIMAGINE® for human Brain Computer Interface applications: toward a clinical trial.
Conference Abstract:
2015 International Workshop on Clinical Brain-Machine Interfaces (CBMI2015).
doi: 10.3389/conf.fnhum.2015.218.00028
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Received:
23 Apr 2015;
Published Online:
29 Apr 2015.
*
Correspondence:
Dr. Guillaume Charvet, CEA/LETI, MINATEC Campus, Grenoble, France, guillaume.charvet@cea.fr