Decoding of Multiple Wrist and Hand Movements Using a Transient EMG Classifier

: The design of prosthetic controllers by means of neurophysiological signals still poses a crucial challenge to bioengineers. State of the art of electromyographic (EMG) continuous pattern recognition controllers rely on the questionable assumption that repeated muscular contractions produce repeatable patterns of steady-state EMG signals. Conversely, we propose an algorithm that decodes wrist and hand movements by processing the signals that immediately follow the onset of contraction (i.e., the transient EMG). We collected EMG data from the forearms of 14 non-amputee and 5 transradial amputee participants while they performed wrist flexion/extension, pronation/supination, and four hand grasps (power, lateral, bi-digital, open). We firstly identified the combination of wrist and hand movements that yielded the best control performance for the same participant (intra-subject classification). Then, we assessed the ability of our algorithm to classify participant data that were not included in the training set (cross-subject classification). Our controller achieved a median accuracy of ~96% with non-amputees, while it achieved heterogeneous outcomes with amputees, with a median accuracy of ~89%. Importantly, for each amputee, it produced at least one acceptable combination of wrist-hand movements (i.e., with accuracy >85%). Regarding the cross-subject classifier, while our algorithm obtained promising results with non-amputees (accuracy up to ~80%), they were not as good with amputees (accuracy up to ~35%), possibly suggesting further assessments with domain-adaptation strategies. In general, our offline outcomes, together with a preliminary online assessment, support the hypothesis that the transient EMG decoding could represent a viable pattern recognition strategy, encouraging further online assessments

A highly integrated bionic hand with neural control and feedback for use in daily life

Restoration of sensorimotor function after amputation has remained challenging because of the lack of human-machine interfaces that provide reliable control, feedback, and attachment. Here, we present the clinical implementation of a transradial neuromusculoskeletal prosthesis-a bionic hand connected directly to the user's nervous and skeletal systems. In one person with unilateral below-elbow amputation, titanium implants were placed intramedullary in the radius and ulna bones, and electromuscular constructs were created surgically by transferring the severed nerves to free muscle grafts. The native muscles, free muscle grafts, and ulnar nerve were implanted with electrodes. Percutaneous extensions from the titanium implants provided direct skeletal attachment and bidirectional communication between the implanted electrodes and a prosthetic hand. Operation of the bionic hand in daily life resulted in improved prosthetic function, reduced postamputation, and increased quality of life. Sensations elicited via direct neural stimulation were consistently perceived on the phantom hand throughout the study. To date, the patient continues using the prosthesis in daily life. The functionality of conventional artificial limbs is hindered by discomfort and limited and unreliable control. Neuromusculoskeletal interfaces can overcome these hurdles and provide the means for the everyday use of a prosthesis with reliable neural control fixated into the skeleton

Design and Development of a Magnetically Driven Actuation System for a Soft Total Artificial Heart

According to the latest statistics published by the European Heart Network, cardiovascular diseases are the leading cause of mortality in most European countries. In particular, the major single source of the overall deaths in Europe (19% among men, 20% among women), is the ischaemic heart disease, the principal aetiology of heart failures. Although the heart failure has always been a plight and nowadays is affecting about 26 million people worldwide, to date, the treatment options remain limited: the only optimal and effective solution for end-stage patients is a total heart transplant. Due to the degenerative nature of the disease and the paucity of available donors, since the late 50s, one of the most ambitious and prominent bioengineering challenges has been to design a device able to, not only support, but also completely substitute the functionalities of the human heart. Several solutions were proposed, yet none of them has been deemed sufficiently reliable to be used as destination therapy, leaving the hurdle still to be overcome. To date, the SynCardia™ is the only commercially available total artificial heart approved by FDA. It is basically a pneumatic pump, supplied by percutaneous drivelines. Although it has been successfully implanted in more than 1300 people, it is still used as only bridge to transplant device and does not represent a permanent solution. The emerging field of soft robotics could provide a breakthrough solution to the problem. Thanks to the incredible number of application fields, the possibility to use materials already (or easy to make) biocompatible, the safe human-robot interaction, but also the lightness, the easily reproducible and cheap technological alternatives, this field is an optimal starting point for artificial organs applications. In this view, this thesis aims at presenting the theoretical basis for a feasibility study of a magnetically-operated device, able to replicate the physiological pumping functionalities of the ventricle of a human heart. Analytical and FEM based models of a left ventricle-like chamber have been developed and set of tests have been conducted on the first prototypes. The results show an overall volume of 132 ml with a potential ejection fraction of 76% against the 62% of human heart. Although several improvements are necessary, particularly regarding the bulkiness of the actuation system, these outcomes constitute a good starting point for the analysed technology, providing optimal room for improvement, particularly concerning the adaptability, the scalability and the potential customisation of the device