Overview of the implant of intraneural multielectrodes in human for controlling a 5-fingered hand prosthesis, delivering sensorial feedback and producing rehabilitative neuroplasticity

In spite of critical rearrangements following amputation, recent findings show how neural connections can be exploited by neural interfaces. Four intraneural multielectrodes have been implanted in an amputee´s for four weeks for recording neural signals and eliciting sensorial feedback. Recorded neural signals were mapped in real-time onto three actions of the robotic hand through amplitude on the best matching channel threshold method, with an 85% accuracy achieved thanks to an AI classifier trained offline. When analyzed only in time windows compatible with the transmission delay of the motor command from the cortex, identified as an event related desynchronization of the electroencephalographic (EEG) rhythm, reliability reached almost 100%. Training for robotic hand control and for sensory perception produced normalization in the EEG activation pattern and a reorganization of the motor cortical maps distinguished by TMS, with restriction of the cortical overrepresentation of muscles proximal to the stump. In parallel, a clinical improvement of phantom limb pain has been observed, that recognizes in the correction of the aberrant plasticity its anatomical substrate. Purpose of this paper is to give a comprehensive overview of all the results obtained from the in-human implant experiment and to critically compare it with previous similar experiences.