Browsing by Author "Raspopovic, Stanisa (14036337200)"

Lower limb amputation (LLA) destroys the sensory communication between the brain and the external world during standing and walking. Current prostheses do not restore sensory feedback to amputees, who, relying on very limited haptic information from the stump-socket interaction, are forced to deal with serious issues: the risk of falls, decreased mobility, prosthesis being perceived as an external object (low embodiment), and increased cognitive burden. Poor mobility is one of the causes of eventual device abandonment. Restoring sensory feedback from the missing leg of above-knee (transfemoral) amputees and integrating the sensory feedback into the sensorimotor loop would markedly improve the life of patients. In this study, we developed a leg neuroprosthesis, which provided real-time tactile and emulated proprioceptive feedback to three transfemoral amputees through nerve stimulation. The feedback was exploited in active tasks, which proved that our approach promoted improved mobility, fall prevention, and agility. We also showed increased embodiment of the lower limb prosthesis (LLP), through phantom leg displacement perception and questionnaires, and ease of the cognitive effort during a dual-task paradigm, through electroencephalographic recordings. Our results demonstrate that induced sensory feedback can be integrated at supraspinal levels to restore functional abilities of the missing leg. This work paves the way for further investigations about how the brain interprets different artificial feedback strategies and for the development of fully implantable sensory-enhanced leg neuroprostheses, which could drastically ameliorate life quality in people with disability. Copyright © 2019 The Authors,

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Amputations have a devastating impact on patients' health with consequent psychological distress, economic loss, difficult reintegration into society, and often low embodiment of standard prosthetic replacement. The main characteristic of bionic limbs is that they establish an interface between the biological residuum and an electronic device, providing not only motor control of prosthesis but also sensitive feedback. Bionic limbs can be classified into three main groups, according to the type of the tissue interfaced: nervetransferred muscle interfacing (targeted muscular reinnervation), direct muscle interfacing and direct nerve interfacing. Targeted muscular reinnervation (TMR) involves the transfer of the remaining nerves of the amputated stump to the available muscles. With direct muscle interfacing, direct intramuscular implants record muscular contractions which are then wirelessly captured through a coil integrated in the socket to actuate prosthesis movement. The third group is the direct interfacing of the residual nerves using implantable electrodes that enable reception of electric signals from the prosthetic sensors. This can improve sensation in the phantom limb. The surgical procedure for electrode implantation consists of targeting the proximal nerve area, competently introducing, placing, and fixing the electrodes and cables, while retaining movement of the arm/leg and nerve, and avoiding excessive neural damage. Advantages of bionic limbs are: the improvement of sensation, improved reintegration/embodiment of the artificial limb, and better controllability. © 2020 The author(s).