Bimanual Motor Strategies and Handedness Role During Human-Exoskeleton Haptic Interaction

Bimanual object manipulation involves multiple visuo-haptic sensory feedbacks arising from the interaction with the environment that are managed from the central nervous system and consequently translated in motor commands. Kinematic strategies that occur during bimanual coupled tasks are still a scientific debate despite modern advances in haptics and robotics. Current technologies may have the potential to provide realistic scenarios involving the entire upper limb extremities during multi-joint movements but are not yet exploited to their full potential. The present study explores how hands dynamically interact when manipulating a shared object through the use of two impedance-controlled exoskeletons programmed to simulate bimanually coupled manipulation of virtual objects. We enrolled twenty-six participants (2 groups: right-handed and left-handed) who were requested to use both hands to grab simulated objects across the robot workspace and place them in specific locations. The virtual objects were rendered with different dynamic proprieties and textures influencing the manipulation strategies to complete the tasks. Results revealed that the roles of hands are related to the movement direction, the haptic features, and the handedness preference. Outcomes suggested that the haptic feedback affects bimanual strategies depending on the movement direction. However, left-handers show better control of the force applied between the two hands, probably due to environmental pressures for right-handed manipulations

Adaptive model-based myoelectric control for a soft wearable arm exosuit:A new generation of wearable robot control

Despite advances in mechatronic design, the widespread adoption of wearable robots for supporting human mobility has been hampered by 1) ergonomic limitations in rigid exoskeletal structures and 2) the lack of human-machine interfaces (HMIs) capable of sensing musculoskeletal states and translating them into robot-control commands. We have developed a framework that combines, for the first time, a model-based HMI with a soft wearable arm exosuit that has the potential to address key limitations in current HMIs and wearable robots. The proposed framework was tested on six healthy subjects who performed elbow rotations across different joint velocities and lifting weights. The results showed that the model-controlled exosuit operated synchronously with biological muscle contraction. Remarkably, the exosuit dynamically modulated mechanical assistance across all investigated loads, thereby displaying adaptive behavior

Pattern of care for re-irradiation in locally recurrent rectal cancer: a national survey on behalf of the AIRO gastrointestinal tumors study group

PurposeRadical resection (R0) represents the best curative treatment for local recurrence (LR) rectal cancer. Re-irradiation (re-RT) can increase the rate of R0 resection. Currently, there is a lack of guidelines on Re-RT for LR rectal cancer. The Italian Association of Radiation and clinical oncology for gastrointestinal tumors (AIRO-GI) study group released a national survey to investigate the current clinical practice of external beam radiation therapy in these patients.Material and methodsIn February 2021, the survey was designed and distributed to members of the GI working group. The questionnaire consisted of 40 questions regarding center characteristics, clinical indications, doses, and treatment techniques of re-RT for LR rectal cancer.ResultsA total of 37 questionnaires were collected. Re-RT was reported as an option for neoadjuvant treatment in resectable and unresectable disease by 55% and 75% of respondents, respectively. Long-course treatment with 30-40 Gy (1.8-2 Gy/die, 1.2 Gy bid) and hypofractionated regimen of 30-35 Gy in 5 fractions were used in most centers. A total dose of 90-100 Gy as EqD2 dose (& alpha;/& beta; = 5 Gy) was delivered by 46% of the respondents considering the previous treatment. Modern conformal techniques and daily image-guided radiation therapy protocols were used in 94% of centers.ConclusionOur survey showed that re-RT treatment is performed with advanced technology that allow a good management of LR rectal cancer. Significant variations were observed in terms of dose and fractionation, highlighting the need for a consensus on a common treatment strategy that could be validated in prospective studies

Position sense and force control: assessment in unimanual and bimanual tasks

Human-environment interactions are common natural occurrences affecting every action. The environment includes objects whose manipulation requires careful somatosensory integration. For successful manipulation, the nervous system must be able to represent and predict the geometrical and mechanical features of sensory stimuli arising from the interaction with objects. These interactions involve sensory perturbations that must be predicted and compensated by the nervous system. Despite the importance of somatosensory integration, a comprehensive understanding of how the unimpaired sensory-motor system integrates information on force and position remains elusive. Over the last decades, the evolution of technology has allowed researchers to develop highly controllable settings for evaluating sensory-motor integration and delivering haptic feedback. However, most of the existing haptic setups consist of systems with limited workspace and reduced-force capabilities. Recent advancements in exoskeleton devices provide a framework for developing haptic setups adequate to cover the full-human range of motion and offer a wide range of force and torque. Moreover, considering the prevalence of real-life activities involving two hands, bimanual control should be implemented and integrated in virtual reality and haptic interfaces. The aim of my thesis project was to understand proprioception and force control in unimanual tasks and extend from that to bimanual and multi-joint tasks. To do this, I developed six setups (three unimanual and three bimanual), which progressively increased the complexity of the technologies employed and the human movements examined, to investigate motor strategies in unimpaired subjects. In the first unimanual setup, I enrolled 36 subjects to study with a planar manipulandum how subjects control the contact force exerted by their dominant arm in predictable (known arm position) and unpredictable (unknown arm position) environments. I was surprised to observe that contact forces can be precisely controlled with variable contact impedance, that is, without a persistent relation between applied force and resulting motion. In the second unimanual task, I investigated how proprioception of wrist position is affected by different types of kinesthetic perturbations of multi-joint arm movements. I enrolled 18 healthy subjects employing a 3-DoFs wrist device. Results evidenced important findings that should also be considered in the clinical evaluation of neurological patients: testing patients\u2019 proprioception in a configuration that is close to the joints\u2019 physiological workspace limits may increase mechanoreceptors excitation and provide a fine measurement of sensory acuity. Finally, in the third unimanual setup, since the proprioception involving the concurrent evaluation of proximal and distal multi-joint (more than a single DoF) upper limbs movements remained an open question, I evaluated 18 healthy participants wearing a robotic exoskeleton. Even in this application, results have relevance to common clinical practice: standard proprioceptive tests are manually dispensed by the therapists, the use of similar wearable technologies that contemplate a multi\u2010joint and 3D-space evaluation could drastically improve measurement accuracy and reliability. Regarding the bimanual studies, in the first one, I evaluated 12 young participants controlling position and force while orienting an object with both hands. To approximate a scenario common to daily living activities, I designed an instrumented stand-alone device and implemented a coupled task oriented to assess bimanual proprioception. Results showed how much the perception of one's body in space affects the proprioceptive acuity for targets near to or far from the body. Proper changes in the evaluation protocol suggest the possible use in the clinical practice of such low-cost instrumentation. The same device was employed even in the second setup. In this case, it was opportunely fixed to make the task decoupled and used to evaluate the bimanual coordination in isometric force control. Compared to other studies, investigating the sole fingers\u2019 contribution, here I considered the full arm by involving both proximal and distal muscles. Two populations were evaluated: young and elderly subjects. The inclusion of elderly subjects introduces insights about the deterioration of human abilities including higher asymmetry, lower accuracy, and more variable performance. Even this setup, appropriately modulated, may be adopted by therapists to evaluate neurological patients. Finally, with the third setup, I designed a task in which subjects performed multi-joint upper limb reaching movements in 3D-space while manipulating a virtual object with variable compliances, i.e., that should handle with less/more care. I re-programmed a bimanual robotic exoskeleton to provide several forms of haptic feedback. I tested the potentiality and the system stability on 15 healthy subjects of this new technology to evaluate motor strategies in the presence of simulated objects capable of reproducing more or less deformable materials. This last application provides a fully-customized environment that should be introduced even in rehabilitative applications requiring the bimanual control of concurrent position and force sense while haptic feedback is provided. Accurately assessing proprioceptive deficits can complement regular therapy to better predict the recovery path. Moreover, bimanual haptic interfaces could provide solutions to clinical evaluation or motor recovery treatment of patients with neurological damages, increasing the efficiency of training and reducing the amount of individual attention needed from the clinician. My outcomes on healthy subjects denote the potentialities of the designed and/or implemented device, tasks, and haptic interface. In particular, they denote a starting point for fully customized environments which could have implications for several assessment or rehabilitative interventions in patients with neurological diseases

"We can't wait any longer": Penelope Fitzgerald tra autobiografia e romanzo storico

Penelope Fitzgerald, autrice di fine Novecento, comincia la sua carriera di scrittrice molto tardi, quando ha quasi sessant'anni. Molte delle sue esperienze di lavoro e di vita le forniranno un grande raccolto per i suoi romanzi. Inizia con lo scrivere romanzi autobiografici e finisce, a ottant'anni, scrivendo romanzi storici. La tesi andrà ad analizzare le due diverse fasi della scrittrice soffermandosi su 2 romanzi della prima fase e 2 romanzi della seconda fase che serviranno anche ad esaminare la storia dell'autobiografia e del romanzo storico più in generale

Rendering Immersive Haptic Force Feedback via Neuromuscular Electrical Stimulation

Haptic feedback is the sensory modality to enhance the so-called “immersion”, meant as the extent to which senses are engaged by the mediated environment during virtual reality applications. However, it can be challenging to meet this requirement using conventional robotic design approaches that rely on rigid mechanical systems with limited workspace and bandwidth. An alternative solution can be seen in the adoption of lightweight wearable systems equipped with Neuromuscular Electrical Stimulation (NMES): in fact, NMES offers a wide range of different forces and qualities of haptic feedback. In this study, we present an experimental setup able to enrich the virtual reality experience by employing NMES to create in the antagonists’ muscles the haptic sensation of being loaded. We developed a subject-specific biomechanical model that estimated elbow torque during object lifting to deliver suitable electrical muscle stimulations. We experimentally tested our system by exploring the differences between the implemented NMES-based haptic feedback (NMES condition), a physical lifted object (Physical condition), and a condition without haptic feedback (Visual condition) in terms of kinematic response, metabolic effort, and participants’ perception of fatigue. Our results showed that both in terms of metabolic consumption and user fatigue perception, the condition with electrical stimulation and the condition with the real weight differed significantly from the condition without any load: the implemented feedback was able to faithfully reproduce interactions with objects, suggesting its possible application in different areas such as gaming, work risk assessment simulation, and education

Three-Dimensional Assessment of Upper Limb Proprioception via a Wearable Exoskeleton

Proprioception—the sense of body segment’s position and movement—plays a crucial role in human motor control, integrating the sensory information necessary for the correct execution of daily life activities. Despite scientific evidence recognizes that several neurological diseases hamper proprioceptive encoding with consequent inability to correctly perform movements, proprioceptive assessment in clinical settings is still limited to standard scales. Literature on physiology of upper limb’s proprioception is mainly focused on experimental approaches involving planar setups, while the present work provides a novel paradigm for assessing proprioception during single—and multi-joint matching tasks in a three-dimensional workspace. To such extent, a six-degrees of freedom exoskeleton, ALEx-RS (Arm Light Exoskeleton Rehab Station), was used to evaluate 18 healthy subjects’ abilities in matching proprioceptive targets during combined single and multi-joint arm’s movements: shoulder abduction/adduction, shoulder flexion/extension, and elbow flexion/extension. Results provided evidence that proprioceptive abilities depend on the number of joints simultaneously involved in the task and on their anatomical location, since muscle spindles work along their preferred direction, modulating the streaming of sensory information accordingly. These findings suggest solutions for clinical sensorimotor evaluation after neurological disease, where assessing proprioceptive deficits can improve the recovery path and complement the rehabilitation outcomes

Recovery of Distal Arm Movements in Spinal Cord Injured Patients with a Body-Machine Interface: A Proof-of-Concept Study

Background: The recovery of upper limb mobility and functions is essential for people with cervical spinal cord injuries (cSCI) to maximize independence in daily activities and ensure a successful return to normality. The rehabilitative path should include a thorough neuromotor evaluation and personalized treatments aimed at recovering motor functions. Body-machine interfaces (BoMI) have been proven to be capable of harnessing residual joint motions to control objects like computer cursors and virtual or physical wheelchairs and to promote motor recovery. However, their therapeutic application has still been limited to shoulder movements. Here, we expanded the use of BoMI to promote the whole arm’s mobility, with a special focus on elbow movements. We also developed an instrumented evaluation test and a set of kinematic indicators for assessing residual abilities and recovery. Methods: Five inpatient cSCI subjects (four acute, one chronic) participated in a BoMI treatment complementary to their standard rehabilitative routine. The subjects wore a BoMI with sensors placed on both proximal and distal arm districts and practiced for 5 weeks. The BoMI was programmed to promote symmetry between right and left arms use and the forearms’ mobility while playing games. To evaluate the effectiveness of the treatment, the subjects’ kinematics were recorded while performing an evaluation test that involved functional bilateral arms movements, before, at the end, and three months after training. Results: At the end of the training, all subjects learned to efficiently use the interface despite being compelled by it to engage their most impaired movements. The subjects completed the training with bilateral symmetry in body recruitment, already present at the end of the familiarization, and they increased the forearm activity. The instrumental evaluation confirmed this. The elbow motion’s angular amplitude improved for all subjects, and other kinematic parameters showed a trend towards the normality range. Conclusion: The outcomes are preliminary evidence supporting the efficacy of the proposed BoMI as a rehabilitation tool to be considered for clinical practice. It also suggests an instrumental evaluation protocol and a set of indicators to assess and evaluate motor impairment and recovery in cSCI