Giulio Rosati

Design, Implementation and Clinical Tests of a Wire-Based Robot for Neurorehabilitation

This paper presents the development of and clinical tests on NeReBot (NEuroREhabilitation roBOT): a three degrees-of-freedom (DoF), wire-driven robot for poststroke upper-limb rehabilitation. Basically, the robot consists of a set of three wires independently driven by three electric motors. The wires are connected to the patients upper limb by means of a splint and are supported by a transportable frame, located above the patient. By controlling wire length, rehabilitation treatment (based on the passive or active-assistive spatial motion of the limb) can be delivered over a wide working space. The arm trajectory is set by the therapist through a very simple teaching-by-showing procedure, enabling most common ldquohands onrdquo therapy exercises to be reproduced by the robot. Compared to other rehabilitation robots, NeReBot offers the advantages of a low-cost mechanical structure, intrinsically safe treatment thanks to the use of wires, high acceptability by the patient, who does not feel constrained by an ldquoindustrial-likerdquo robot, transportability (it can be easily placed aside a hospital bed and/or a wheelchair), and a good trade-off between low number of DoF and spatial performance. These features and the very encouraging results of the first clinical trials make the NeReBot a good candidate for adoption in the rehabilitation treatment of subacute stroke survivors. Clinical trials were performed with a 12-patient experimental group and a 12-patient control group. Resulted that the patients who received robotic therapy in addition to conventional therapy showed greater reductions in motor impairment (in terms of Medical Research Council score, the upper limb subsection of the Fugl-Meyer score, and the Motor Status Score) and improvements in functional abilities (as measured by the Functional Independence Measure and its motor component). No adverse effects occurred and the robotic approach was very well accepted. According to these results, the NeReBot therapy may efficaciously complement standard poststroke multidisciplinary rehabilitation and offer novel therapeutic strategies for neurological rehabilitation.

Cutaneous Force Feedback as a Sensory Subtraction Technique in Haptics

A novel sensory substitution technique is presented. Kinesthetic and cutaneous force feedback are substituted by cutaneous feedback (CF) only, provided by two wearable devices able to apply forces to the index finger and the thumb, while holding a handle during a teleoperation task. The force pattern, fed back to the user while using the cutaneous devices, is similar, in terms of intensity and area of application, to the cutaneous force pattern applied to the finger pad while interacting with a haptic device providing both cutaneous and kinesthetic force feedback. The pattern generated using the cutaneous devices can be thought as a subtraction between the complete haptic feedback (HF) and the kinesthetic part of it. For this reason, we refer to this approach as sensory subtraction instead of sensory substitution. A needle insertion scenario is considered to validate the approach. The haptic device is connected to a virtual environment simulating a needle insertion task. Experiments show that the perception of inserting a needle using the cutaneous-only force feedback is nearly indistinguishable from the one felt by the user while using both cutaneous and kinesthetic feedback. As most of the sensory substitution approaches, the proposed sensory subtraction technique also has the advantage of not suffering from stability issues of teleoperation systems due, for instance, to communication delays. Moreover, experiments show that the sensory subtraction technique outperforms sensory substitution with more conventional visual feedback (VF).

Upper-Limb Robot-Assisted Therapy in Rehabilitation of Acute Stroke Patients: Focused Review and Results of New Randomized Controlled Trial

The successful motor rehabilitation of stroke patients requires early intensive and task-specific therapy. A recent Cochrane Review, although based on a limited number of randomized controlled trials (RCTs), showed that early robotic training of the upper limb (i.e., during acute or subacute phase) can enhance motor learning and improve functional abilities more than chronic-phase training. In this article, a new subacute-phase RCT with the Neuro-Rehabilitation-roBot (NeReBot) is presented. While in our first study we used the NeReBot in addition to conventional therapy, in this new trial we used the same device in substitution of standard proximal upper-limb rehabilitation. With this protocol, robot patients achieved similar reductions in motor impairment and enhancements in paretic upper-limb function to those gained by patients in a control group. By analyzing these results and those of previous studies, we hypothesize a new robotic protocol for acute and subacute stroke patients based on both treatment modalities (in addition and in substitution).

Effect of visual distraction and auditory feedback on patient effort during robot-assisted movement training after stroke

BackgroundPracticing arm and gait movements with robotic assistance after neurologic injury can help patients improve their movement ability, but patients sometimes reduce their effort during training in response to the assistance. Reduced effort has been hypothesized to diminish clinical outcomes of robotic training. To better understand patient slacking, we studied the role of visual distraction and auditory feedback in modulating patient effort during a common robot-assisted tracking task.MethodsFourteen participants with chronic left hemiparesis from stroke, five control participants with chronic right hemiparesis and fourteen non-impaired healthy control participants, tracked a visual target with their arms while receiving adaptive assistance from a robotic arm exoskeleton. We compared four practice conditions: the baseline tracking task alone; tracking while also performing a visual distracter task; tracking with the visual distracter and sound feedback; and tracking with sound feedback. For the distracter task, symbols were randomly displayed in the corners of the computer screen, and the participants were instructed to click a mouse button when a target symbol appeared. The sound feedback consisted of a repeating beep, with the frequency of repetition made to increase with increasing tracking error.ResultsParticipants with stroke halved their effort and doubled their tracking error when performing the visual distracter task with their left hemiparetic arm. With sound feedback, however, these participants increased their effort and decreased their tracking error close to their baseline levels, while also performing the distracter task successfully. These effects were significantly smaller for the participants who used their non-paretic arm and for the participants without stroke.ConclusionsVisual distraction decreased participants effort during a standard robot-assisted movement training task. This effect was greater for the hemiparetic arm, suggesting that the increased demands associated with controlling an affected arm make the motor system more prone to slack when distracted. Providing an alternate sensory channel for feedback, i.e., auditory feedback of tracking error, enabled the participants to simultaneously perform the tracking task and distracter task effectively. Thus, incorporating real-time auditory feedback of performance errors might improve clinical outcomes of robotic therapy systems.

Manipulability of a planar wire driven haptic device

This paper presents a planar 4 wire driven 3-DOF mechanism. For a planar haptic interface, this device could provide planar forces and moment feedback to the human operator. The particular end-effector geometric configuration overcomes manipulability problems arising from other recent planar wire haptic interfaces [R.L. Williams II, Int. J. Virtual Reality 3 (3) (1998) 13]. Moreover, an explicit forward kinematic pose solution is obtained by introducing a modified wire configuration. Complete kinematic and manipulability analyses are presented.

3-d.o.f. Wire Driven Planar Haptic Interface

A 4-wire driven 3-d.o.f. planar haptic device, called the Feriba-3, is described. The particular geometric configuration of the end-effector ensures a closed form kinematic pose solution and good manipulability. Moreover, the structural arrangement adopted makes the Feriba-3 a well-performing haptic device, whose major features are low inertia, low friction, and full dexterity in a large workspace. The manipulability analysis has been performed by introducing a complete set of manipulability indices.

Upper limb rehabilitation robotics after stroke: a perspective from the University of Padua, Italy.

Rehabilitation robotics is an emerging research field that aims to employ leading-edge robotic technology and virtual reality systems in the rehabilitation treatment of neuro-logical patients. In post-stroke patients with upper limb impairment, clinical trials have so far shown positive results in terms of motor recovery, but poor efficacy in terms of functional outcome. Much work is needed to develop a new generation of rehabilitation robots and clinical protocols that will be more effective in helping patients to regain their abilities in activities of daily living. This paper presents some key issues in the future perspective of upper limb robotic rehabilitation after stroke.

Design of a new 5 d.o.f. wire-based robot for rehabilitation

In the last three years, a wire-based robot called the NeReBot (neurorehabilitation robot) was developed at the Robotics Laboratory of the Department of Innovation in Mechanics and Management, University of Padua, Italy. NeReBot is a 3 degrees-of-freedom (d.o.f.) wire-based robot, designed for the treatment of patients with stroke-related paralyzed or paretic upper limb during the acute phase. Although first clinical tests showed encouraging results in terms of motor recovery and functional outcome, the robot presented some limitations. Hence a new wire-based robot, called the MariBot (Marisa robot), was designed. The wire-drive philosophy, which makes the robot intrinsically safe, was maintained. Nevertheless, by changing the mechanical structure and adding two more d.o.f. the working space was enlarged significantly. Moreover, thanks to the improved mechanical design, MariBot results much lighter and less cumbersome than NeReBot. Finally, electronic hardware and control software were changed in order to improve man-machine interaction. In this paper, starting from the NeReBot experience, the design of MariBot is presented.

Randomized Trial of a Robotic Assistive Device for the Upper Extremity During Early Inpatient Stroke Rehabilitation

Background. A recent Cochrane Review showed that early robotic training of the upper limb in stroke survivors can be more effective than other interventions when improving activities of daily living involving the arm function is the aim of therapy. Objective. We tested for efficacy of the study a protocol which involved the use of the NeReBot therapy in partial substitution of standard upper limb rehabilitation in post–acute stroke patients. Methods. In this dose-matched, randomized controlled clinical trial, 34 hemiparetic participants with movement against gravity in shoulder, elbow, and wrist muscle groups were enrolled within 15 days of the onset of stroke. All participants received a total daily rehabilitation treatment for 120 minutes, 5 days per week for 5 weeks. The control group received standard therapy for the upper limb. The experimental group received standard therapy (65% of exercise time) associated with robotic training (35% of exercise time). Muscle tone (Modified Ashworth Scale), strength (Medical Research Council), and synergism (Fugl-Meyer motor scores) were measured at impairment level, whereas dexterity (Box and Block Test and Frenchay Arm Test) and activities of daily living (Functional Independence Measure) were measured at activity level. All assessments were performed at baseline, at the end of therapy (time T1), at 3 months (time T2), and at 7 months (time T3) after entry. All between-group analyses were tested using nonparametric test with Bonferroni’s adjustments for multiple testing. Results. No significant between-group differences were found with respect to demographic characteristics, motor, dexterity, and ADLs at baseline, postintervention (T1) and at follow-up (T2 and T3). Conclusions. The robot therapy by NeReBot did not lead to better outcomes compared with conventional inpatient rehabilitation.

A novel robot device in rehabilitation of post-stroke hemiplegic upper limbs

Background and aims: In this pilot study, we introduce the “NeReBot”, a novel robotic device designed and programmed for clinical neurological applications. The aim of the study was to test whether additional sensorimotor training of paralyzed or paretic upper limbs, delivered by NeReBot, enhanced motor and functional outcome in stroke patients. Methods: Twenty patients with post-stroke hemiparesis or hemiplegia received standard post-stroke multidisciplinary rehabilitation, and were randomly assigned either to exposure to the robotic device without training or to additional sensorimotor robotic training (about 4 h/week) for 4 weeks. Robot training consisted of peripheral manipulation of the shoulder and elbow of the impaired limb, correlated with visual stimuli. Results: At hospital discharge, impairment and disability had declined in all patients, but the group with robot training showed higher gains on motor impairment and functional recovery, which were maintained at the 3-month follow-up. No adverse events resulted from robot-assisted therapy. Conclusions: According to our results, NeReBot therapy may efficaciously complement standard post-stroke multidisciplinary rehabilitation and offer novel therapeutic strategies for neurological rehabilitation.