28 research outputs found
Kinematics-Based Adaptive Assistance of a Semi-Passive Upper-Limb Exoskeleton for Workers in Static and Dynamic Tasks
Robotic Rehabilitation and Multimodal Instrumented Assessment of Post-stroke Elbow Motor Functions—A Randomized Controlled Trial Protocol
Background: The reliable assessment, attribution, and alleviation of upper-limb joint
stiffness are essential clinical objectives in the early rehabilitation from stroke and other
neurological disorders, to prevent the progression of neuromuscular pathology and
enable proactive physiotherapy toward functional recovery. However, the current clinical
evaluation and treatment of this stiffness (and underlying muscle spasticity) are severely
limited by their dependence on subjective evaluation and manual limb mobilization, thus
rendering the evaluation imprecise and the treatment insufficiently tailored to the specific
pathologies and residual capabilities of individual patients.
Methods: To address these needs, the proposed clinical trial will employ the
NEUROExos Elbow Module (NEEM), an active robotic exoskeleton, for the passive
mobilization and active training of elbow flexion and extension in 60 sub-acute and
chronic stroke patients with motor impairments (hemiparesis and/or spasticity) of the right
arm. The study protocol is a randomized controlled trial consisting of a 4-week functional
rehabilitation program, with both clinical and robotically instrumented assessments to be
conducted at baseline and post-treatment. The primary outcome measures will be a
set of standard clinical scales for upper limb spasticity and motor function assessment,
including the Modified Ashworth Scale and Fugl-Meyer Index, to confirm the safety and
evaluate the efficacy of robotic rehabilitation in reducing elbow stiffness and improving
function. Secondary outcomes will include biomechanical, muscular activity, and motor
performance parameters extracted from instrumented assessments using the NEEM
along with synchronous EMG recordings. The study protocol has been registered on
clinicaltrials.gov with registration trial number NCT04484571.
Conclusions: This randomized controlled trial aims to validate an innovative
instrumented methodology for clinical spasticity assessment and functional rehabilitation,
relying on the precision and accuracy of an elbow exoskeleton combined with EMG
recordings and the expertise of a physiotherapist, thus complementing and maximizing
the benefits of both practices
Self-Aligning Finger Exoskeleton for the Mobilization of the Metacarpophalangeal Joint
In the context of hand and finger rehabilitation,
kinematic compatibility is key for the acceptability
and clinical exploitation of robotic devices. Different kinematic
chain solutions have been proposed in the state of
the art, with different trade-offs between characteristics
of kinematic compatibility, adaptability to different anthropometries,
and the ability to compute relevant clinical
information. This study presents the design of a novel
kinematic chain for the mobilization of the metacarpophalangeal
(MCP) joint of the long fingers and a mathematical
model for the real-time computation of the joint angle and
transferred torque. The proposed mechanism can self-align
with the human joint without hindering force transfer or
inducing parasitic torque. The chain has been designed
for integration into an exoskeletal device aimed at rehabilitating
traumatic-hand patients. The exoskeleton actuation
the unit has a series-elastic architecture for compliant human-robot
interaction and has been assembled and preliminarily
tested in experiments with eight human subjects. Performance
has been investigated in terms of (i) the accuracy of
the MCP joint angle estimation through comparison with
a video-based motion tracking system, (ii) residual MCP
torque when the exoskeleton is controlled to provide null
output impedance and (iii) torque-tracking performance.
Results showed a root-mean-square error (RMSE) below
5 degrees in the estimated MCP angle. The estimated residual
MCP torque resulted below 7 mNm. Torque tracking performance
shows an RMSE lower than 8 mNm in following
sinusoidal reference profiles. The results encourage further
investigations of the device in a clinical scenario
Physiological Responses During Hybrid BNCI Control of an Upper-Limb Exoskeleton
When combined with assistive robotic devices, such as wearable robotics,
brain/neural-computer interfaces (BNCI) have the potential to restore the capabilities of handicapped
people to carry out activities of daily living. To improve applicability of such systems, workload and
stress should be reduced to a minimal level. Here, we investigated the user’s physiological reactions
during the exhaustive use of the interfaces of a hybrid control interface. Eleven BNCI-naive healthy
volunteers participated in the experiments. All participants sat in a comfortable chair in front of a
desk and wore a whole-arm exoskeleton as well as wearable devices for monitoring physiological,
electroencephalographic (EEG) and electrooculographic (EoG) signals. The experimental protocol
consisted of three phases: (i) Set-up, calibration and BNCI training; (ii) Familiarization phase ; and (iii)
Experimental phase during which each subject had to perform EEG and EoG tasks. After completing
each task, the NASA-TLX questionnaire and self-assessment manikin (SAM) were completed by
the user. We found significant differences (p-value < 0.05) in heart rate variability (HRV) and skin
conductance level (SCL) between participants during the use of the two different biosignal modalities
(EEG, EoG) of the BNCI. This indicates that EEG control is associated with a higher level of stress
(associated with a decrease in HRV) and mental work load (associated with a higher level of SCL)
when compared to EoG control. In addition, HRV and SCL modulations correlated with the subject’s
workload perception and emotional responses assessed through NASA-TLX questionnaires and SAM
A low-power ankle-foot prosthesis for push-off enhancement
Passive ankle-foot prostheses are light-weighted and reliable, but they cannot generate net positive power, which is essential in restoring the natural gait pattern of amputees. Recent robotic prostheses addressed the problem by actively controlling the storage and release of energy generated during the stance phase through the mechanical deformation of elastic elements housed in the device. This study proposes an innovative low-power active prosthetic module that fits on off-the-shelf passive ankle-foot energy-storage-and-release (ESAR) prostheses. The module is placed parallel to the ESAR foot, actively augmenting the energy stored in the foot and controlling the energy return for an enhanced push-off. The parallel elastic actuation takes advantage of the amputee’s natural loading action on the foot’s elastic structure, retaining its deformation. The actuation unit is designed to additionally deform the foot and command the return of the total stored energy. The control strategy of the prosthesis adapts to changes in the user’s cadence and loading conditions to return the energy at a desired stride phase. An early verification on two transtibial amputees during treadmill walking showed that the proposed mechanism could increase the subjects’ dorsiflexion peak of 15.2% and 41.6% for subjects 1 and 2, respectively, and the cadence of about 2%. Moreover, an increase of 26% and 45% was observed in the energy return for subjects 1 and 2, respectively
Hybrid brain/neural interface and autonomous vision-guided whole-arm exoskeleton control to perform activities of daily living (ADLs)
[EN] Background
The aging of the population and the progressive increase of life expectancy in developed countries is leading to a high incidence of age-related cerebrovascular diseases, which affect people's motor and cognitive capabilities and might result in the loss of arm and hand functions. Such conditions have a detrimental impact on people's quality of life. Assistive robots have been developed to help people with motor or cognitive disabilities to perform activities of daily living (ADLs) independently. Most of the robotic systems for assisting on ADLs proposed in the state of the art are mainly external manipulators and exoskeletal devices. The main objective of this study is to compare the performance of an hybrid EEG/EOG interface to perform ADLs when the user is controlling an exoskeleton rather than using an external manipulator.
Methods
Ten impaired participants (5 males and 5 females, mean age 52 +/- 16 years) were instructed to use both systems to perform a drinking task and a pouring task comprising multiple subtasks. For each device, two modes of operation were studied: synchronous mode (the user received a visual cue indicating the sub-tasks to be performed at each time) and asynchronous mode (the user started and finished each of the sub-tasks independently). Fluent control was assumed when the time for successful initializations ranged below 3 s and a reliable control in case it remained below 5 s. NASA-TLX questionnaire was used to evaluate the task workload. For the trials involving the use of the exoskeleton, a custom Likert-Scale questionnaire was used to evaluate the user's experience in terms of perceived comfort, safety, and reliability.
Results
All participants were able to control both systems fluently and reliably. However, results suggest better performances of the exoskeleton over the external manipulator (75% successful initializations remain below 3 s in case of the exoskeleton and bellow 5s in case of the external manipulator).
Conclusions
Although the results of our study in terms of fluency and reliability of EEG control suggest better performances of the exoskeleton over the external manipulator, such results cannot be considered conclusive, due to the heterogeneity of the population under test and the relatively limited number of participants.This study was funded by the European Commission under the project AIDE (G.A. no: 645322), Spanish Ministry of Science and Innovation, through the projects PID2019-108310RB-I00 and PLEC2022-009424 and by the Ministry of Universities and European Union, "fnanced by European Union-Next Generation EU" through Margarita Salas grant for the training of young doctors.Catalán, JM.; Trigili, E.; Nann, M.; Blanco-Ivorra, A.; Lauretti, C.; Cordella, F.; Ivorra, E.... (2023). Hybrid brain/neural interface and autonomous vision-guided whole-arm exoskeleton control to perform activities of daily living (ADLs). Journal of NeuroEngineering and Rehabilitation. 20(1):1-16. https://doi.org/10.1186/s12984-023-01185-w11620
Study and development of a soft semi-active rotational joint for wearable robotics
In recent times, wearable robotics has rapidly gained increasing consideration in medical field: powered exoskeletons can work in close contact with the human body, to provide assistance for daily-living activities, but also as powerful tools for rehabilitation. A key challenge in their design is the kinematic compliance toward the addressed body segments, so that the exoskeleton and the human joint axes maintain alignment while moving. If this requirement is not satisfied, undesired residual forces will load the human articulations. Currently, this problem is tackled with the addition of passive degrees of freedom, lending additional motions in the robotic joint, to self-compensate the misalignments. Nonetheless, this leads to a more complex, bulky and heavier structure, limiting the robot's wearability.
In this work we developed a soft rotational joint aiming to replace or improve the self-aligning mechanism design. In particular, we evaluated its ability to sustain axial loads while transmitting a torque. Since the soft joint has not inherently the same strength as its rigid counterpart, granular jamming is employed to increase its stiffness. Its design was explored by testing two different membrane materials, and two different contact surfaces between the granular materials. The performances of the prototype were evaluated testing the soft-joint assembled in parallel to a cable-actuated revolute joint, emulating a flexion-extension motion. The experimental setup included an Instron testing machine, to control the cable tension and displacement, and a mono-axial load cell to evaluate the force unloaded through the soft joint during the flexion arc of motion.
The results show that the soft joint is actually able to absorb a substantial part of the applied axial load, without affecting the execution of the movement, with a behavior that is strongly dependent on the type of membrane and grain used and slightly dependent on the velocity of rotation
A Novel Generation of Ergonomic Upper-Limb Wearable Robots: Design Challenges and Solutions
The efficacy of hybrid neuroprostheses in the rehabilitation of upper limb impairment after stroke, a narrative and systematic review with a meta-analysis
Background: Paresis of the upper limb (UL) is the most frequent impairment after a stroke. Hybrid neuroprostheses, i.e., the combination of robots and electrical stimulation, have emerged as an option to treat these impairments. Methods: To give an overview of existing devices, their features, and how they are linked to clinical metrics, four different databases were systematically searched for studies on hybrid neuroprostheses for UL rehabilitation after stroke. The evidence on the efficacy of hybrid therapies was synthesized. Results: Seventy-three studies were identified, introducing 32 hybrid systems. Among the most recent devices (n = 20), most actively reinforce movement (3 passively) and are typical exoskeletons (3 end-effectors). If classified according to the International Classification of Functioning, Disability and Health, systems for proximal support are expected to affect body structures and functions, while the activity and participation level are targeted when applying Functional Electrical Stimulation distally plus the robotic component proximally. The meta-analysis reveals a significant positive effect on UL functions (p < 0.001), evident in a 7.8-point Mdiff between groups in the Fugl-Meyer assessment. This positive effect remains at the 3-month follow-up (Mdiff  = 8.4, p < 0.001). Conclusions: Hybrid neuroprostheses have a positive effect on UL recovery after stroke, with effects persisting at least three months after the intervention. Non-significant studies were those with the shortest intervention periods and the oldest patients. Improvements in UL functions are not only present in the subacute phase after stroke but also in long-term chronic stages. In addition to further technical development, more RCTs are needed to make assumptions about the determinants of successful therapy