Transcranial magnetic stimulation (TMS) based analysis of brain plasticise in face transplantation, arm transplantation and amputee patients

Transcranial Magnetic Stimulation is a noninvasive magnetic stimulation of the motor cortex and motor pathways. Responses obtained from the target muscles through TMS can be evaluated electrophysiologically. Brain plasticity can be described as structural and functional, temporary and permanent synaptic changes of the brain as a response to environmental modifications. Motor representation and sensory representation can be reorganized as a result of the interaction of neurons with neighboring neurons during the readaptation process in case of sudden or long-term loss of facial tissue or limbs. Facial transplantation refers to the transfer of facial tissue from a donor to a patient who lost his/her face due to total denervation. Arm transplant refers to micro-surgical suturing of two arms taken from an eligible donor on a patient who lost both arms as a result of a trauma. Scapular replantation involves micro-surgical coaptation of all arteries, veins, nerves, bones, and muscles with post-traumatic amputation. Motor and sensory innervation of the transplanted facial tissue or limb go through a rehabilitation process to prevent loss of motor movements during recovery and also to accelerate the process. Therefore, the post-transplant process is important for the patient's quality of life. In addition to the cognitive rehabilitation procedure developed by our team, the main goal of this work is to develop an adaptive rehabilitation procedure involving the adaptation of brain dynamics. TMS based cortical mapping was done on three full-face transplant, two double-arm transplant and two scapular replantation cases to describe brain dynamics, to identify and discover structural, functional, temporary and permanent plastic changes and to develop neurophysiologic approaches as the database was created. A control group was formed in order to interpret the cortical map of the transplantation cases. In addition, motor evoked potential (MEP) maps of hand and face representation were individually prepared, and short-interval cortical inhibition (SICI) and intracortical facilitation (ICF) values were analyzed for each case. After filtering the raw data for motor evoked potential created as a result of magnetic stimulation, its location, amplitude and latency were identified by the software developed. Feature extraction analyses were performed and the images were processed. Analysis results were applied on the 3D human model created. The results of transplant cases were individually analysed with clinicians. Neurophysiological differences were found when each transplant case is compared to the control group. I believe that the findings will contribute to the development of the adaptive rehabilitation procedure and individual recovery process of the patient with an accelerating effect.