Article type: Research Article
Authors: Ferreri, F.; | Ponzo, D.; | Vollero, L. | Guerra, A. | Di Pino, G.; | Petrichella, S. | Benvenuto, A. | Tombini, M. | Rossini, L.; | Denaro, L. | Micera, S.; | Iannello, G. | Guglielmelli, E. | Denaro, V. | Rossini, P.M.;
Affiliations: Department of Neurology, University Campus Bio-Medico, Rome, Italy | Department of Clinical Neurophysiology, Kuopio University Hospital, University of Eastern Finland, Kuopio, Finland | Department of Biomedical Research, University Campus Bio-Medico, Rome, Italy | Biomedical Robotics and Biomicrosystems Laboratory, Centre for Integrated Research, University Campus Bio-Medico, Rome, Italy | IRCCS S. Raffaele-Pisana, Rome, Italy | Department of Neurosurgery, Catholic University, Rome, Italy | Advanced Robotics Technology and Systems Laboratory, Scuola Superiore Sant'Anna, Pisa, Italy | Institute for Automation, Swiss Federal Institute of Technology, Zurich, Switzerland | Department of Orthopaedics, Campus Bio-Medico University, Rome, Italy | Institute of Neurology, Catholic University, Rome, Italy
Note: [] Corresponding author: F. Ferreri, Department of Neurology, University Campus Bio-Medico, Rome, Italy. E-mail: f.ferreri@unicampus.it
Note: [] Corresponding author: P.M. Rossini, Institute of Neurology, Catholic University, Rome, Italy. E-mail: paolomaria.rossini@afar.it
Abstract: Purpose: Following limb amputation, central and peripheral nervous system relays partially maintain their functions and can be exploited for interfacing prostheses. The aim of this study is to investigate, for the first time by means of an EEG-TMS co-registration study, whether and how direct bidirectional connection between brain and hand prosthesis impacts on sensorimotor cortical topography. Methods: Within an experimental protocol for robotic hand control, a 26 years-old, left-hand amputated male was selected to have implanted four intrafascicular electrodes (tf-LIFEs-4) in the median and ulnar nerves of the stump for 4 weeks. Before tf-LIFE-4s implant (T0) and after the training period, once electrodes have been removed (T1), experimental subject's cortico-cortical excitability, connectivity and plasticity were tested via a neuronavigated EEG–TMS experiment. Results: The statistical analysis clearly demonstrated a significant modulation (with t-test p < 0.0001) of EEG activity between 30 and 100 ms post-stimulus for the stimulation of the right hemisphere. When studying individual latencies in that time range, a global amplitude modulation was found in most of the TMS-evoked potentials; particularly, the GEE analysis showed significant differences between T0 and T1 condition at 30 ms (p < 0.0404), 46 ms (p < 0.0001) and 60 ms (p < 0.007) latencies. Finally, also a clear local decrement in N46 amplitude over C4 was evident. No differences between conditions were observed for the stimulation of the left hemisphere. Conclusions: The results of this study confirm the hypothesis that bidirectional neural interface could redirect cortical areas -deprived of their original input/output functions- toward restorative neuroplasticity. This reorganization strongly involves bi-hemispheric networks and intracortical and transcortical modulation of GABAergic inhibition.
Keywords: Limb amputation, tf-LIFEs-4, bidirectional neural interface, neuro-plasticity, EEG-TMS co-registration
DOI: 10.3233/RNN-130347
Journal: Restorative Neurology and Neuroscience, vol. 32, no. 2, pp. 281-292, 2014
