Posts Tagged Portable
[ARTICLE] A portable assist-as-need upper-extremity hybrid exoskeleton for FES-induced muscle fatigue reduction in stroke rehabilitation – Full Text
Hybrid exoskeletons are a recent development which combine Functional Electrical Stimulation with actuators to improve both the mental and physical rehabilitation of stroke patients. Hybrid exoskeletons have been shown capable of reducing the weight of the actuator and improving movement precision compared to Functional Electrical Stimulation alone. However little attention has been given towards the ability of hybrid exoskeletons to reduce and manage Functional Electrical Stimulation induced fatigue or towards adapting to user ability. This work details the construction and testing of a novel assist-as-need upper-extremity hybrid exoskeleton which uses model-based Functional Electrical Stimulation control to delay Functional Electrical Stimulation induced muscle fatigue. The hybrid control is compared with Functional Electrical Stimulation only control on a healthy subject.
The hybrid system produced 24° less average angle error and 13.2° less Root Mean Square Error, than Functional Electrical Stimulation on its own and showed a reduction in Functional Electrical Stimulation induced fatigue.
As far as the authors are aware, this is the study which provides evidence of the advantages of hybrid exoskeletons compared to use of Functional Electrical Stimulation on its own with regards to the delay of Functional Electrical Stimulation induced muscle fatigue.
Stroke is the second largest cause of disability worldwide after dementia . Temporary hemiparesis is common among stroke survivors. Regaining strength and movement in the affected side takes time and can be improved with the use of rehabilitation therapy involving repetitive and function-specific tasks . Muscle atrophy is another common issue that occurs after a stroke due to lack of use of the muscle. For each day a patient is in hospital lying in bed with minimal activity approximately 13% of muscular strength is lost (Ellis. Liam, Jackson. Samuel, Liu. Cheng-Yueh, Molloy. Peter, Paterson. Kelsey, Lower Limb Exoskeleton Final Report, unpublished). Electromechanically actuated exoskeletons offer huge advantages in their ability to repetitively and precisely provide assistance/resistance to a user. However electromechanical actuators which provide the required forces are often heavy in weight and have high power requirements which limits portability. Furthermore, muscle atrophy can only be prevented by physically working the muscles either through the patient’s own volition or the use of Functional Electrical Stimulation (FES).
FES is the application of high frequency electrical pulses to the nerves or directly to the muscle belly in order to elicit contractions in the muscle. FES devices are typically lightweight and FES is well suited to reducing muscle atrophy in patients with no or extremely limited movement. The trade off to this is that precise control of FES is extremely difficult and controlling specific, repetitive, and functional movement is not easily accomplished. Furthermore, extended use of FES is limited by the introduction of muscle fatigue caused by the unnatural motor unit recruitment order . The forces required for large movements, such as shoulder abduction, are too great to be provided by the use of FES which is much better suited to smaller movements such as finger extension [4, 5]. Some patients also find the use of FES painful.
Combining the use of FES and an electromechanical actuator within an exoskeleton can potentially overcome the limitations of each individual system. Despite the potential advantages of hybrid exoskeletons, so far only limited studies have been done on their effectiveness. A recent review was conducted into upper-extremity hybrid exoskeletons  which highlighted the advantages hybrid exoskeletons (exoskeletons which combine FES with an actuator) have with regards to improving the precision of FES induced movements. However, little attention has been given towards reduction and management of FES-induced fatigue. FES control systems used for upper-extremity hybrid exoskeletons simply manually ramp up stimulation intensity when fatigue is observed.
This work describes the design and testing of an assist-as-need upper-extremity hybrid exoskeleton which uses model-based control of FES with a focus on reducing FES-induced muscle fatigue. The control system is described in Section “Theory”, and the results are presented in Section “Results”. A discussion of the results is given in Section “Discussion”. Conclusions are summarised in Section “Conclusion”. Methods, physical structure of the exoskeleton, and the sensing system is described in Section “Material and methods”.[…]
A therapeutic shoe engineered to help improve stroke recovery is proving successful and is expected to hit the market by the end of the year, researchers from University of South Florida suggest.
Results from the recently completed clinical trials on the US patented and licensed iStride Device, formerly the Gait Enhancing Mobile Shoe (GEMS), were published recently in the Journal of NeuroEngineering and Rehabilitation.
Gait asymmetry as the result of a stroke is associated with poor balance, a major cause of degenerative issues that make individuals more susceptible to falls and injuries.
The iStride device is designed to be strapped over the shoe of the stroke patient’s good leg and generate a backwards motion, exaggerating the existing step, making it harder to walk while wearing the shoe. The awkward movement strengthens the stroke-impacted leg, allowing gait to become more symmetrical once the shoe is removed. The impaired foot wears a matching shoe that remains stationary, a media release from University of South Florida (USF Innovation) notes.
“The backward motion of the shoe is generated passively by redirecting the wearer’s downward force during stance phase. Since the motion is generated by the wearer’s force, the person is in control, which allows easier adaptation to the motion,” developer Kyle Reed, PhD, associate professor of mechanical engineering at the University of South Florida, says in the release.
“Unlike many of the existing gait rehabilitation devices, this device is passive, portable, wearable and does not require any external energy.”
The trial included six people between ages 57 and 74 who suffered a cerebral stroke at least 1 year prior to the study. They all had asymmetry large enough to impact their walking ability. Each received 12, 30-minute gait training sessions for 4 weeks. With guidance from a physical therapist, the patients’ gait symmetry and functional walking were measured using the ProtoKinetics Zeno Walkway system.
All participants improved their gait’s symmetry and speed. That includes how long it takes to stand up from a sitting position and walk, as well as how long it takes to walk to a specific location and distance traveled within 6 minutes. Four improved the percentage of time spent in a gait cycle with both feet simultaneously planted on the ground, known as double limb support.
As far as the other two that didn’t improve, one started the study with severe impairment, while the other was highly functional. It’s also important to note that three participants joined the study limited to walking in their homes. Following the trial, two of them could successfully navigate public venues, the release explains.
Reed compared his method to a previous study conducted on split-belt treadmill training (SBT), which is commonly used by physical therapists to help stroke patients improve their gait. The equipment allows the legs to move at different speeds, forcing the patient to compensate in order to remain on the treadmill. While the SBT improves certain aspects of gait, unlike the iStride, it doesn’t strengthen double limb support.
That research concluded only about 60% of patients trained on the SBT corrected their gait when walking in a normal environment. Walking is context dependent where visual cues impact how quickly one tries to move, and in what direction. The iStride allows patients to adjust accordingly. Movement on a treadmill is predictable and provides individuals a static scene.
Since patients are often disappointed in their progress after being discharged from rehabilitation, the iStride’s portability allows patients to relearn to walk in a typical setting more often and for a longer duration.
Reed is now working on a home-based clinical trial with 21 participants and expects to publish results within the next year. He recently received a Fulbright scholarship to conduct research at Hong Kong Polytechnic University. He’s working in the rehabilitation sciences and biomedical engineering departments throughout the 2019-2020 academic year, per the release.
[Source(s): University of South Florida (USF Innovation), EurekAlert]
[ARTICLE] Development of low-cost portable hand exoskeleton for assistive and rehabilitation purposes – Full Text PDF
The US Food and Drug Administration (FDA) has granted clearance to MindMotion GO, a portable neurorehabilitation product, for launch in the United States.
MindMotion GO utilizes technology that is designed to be used by patients with mild to lightly severe neurological impairments, as well as in the recovery phase of rehabilitation. Produced by the Swiss neurogaming company MindMaze, the mobile rehabilitation product is an outpatient addition to its MindMotion PRO, which received FDA approval in May 2017.
The PRO version differs from the recently approved MindMotion GO in that it is intended for use in patients with severe impairments as well as in early hospital care—in an inpatient setting—with therapeutic activities able to take place within 4 days after a neurological incident.
“Now that both MindMotion products have FDA clearance, MindMaze delivers a full spectrum of neuro-care solutions for both inpatient and outpatient recovery for patients in the United States,” said Tej Tadi, PhD, the CEO and founder of MindMaze, in a statement. “Our unique capability to safely and securely acquire data through our platform is essential for patient recovery and performance, and positions MindMaze as a powerhouse for the future of brain-machine interfaces. Beyond healthcare, this will enable powerful AI-based applications. We are working on a range of brain-tech initiatives at MindMaze to build the infrastructure for innovations to improve patients’ quality of life.”
The mobile MindMotion GO allows for real-time audio and visual feedback, aiding physicians in the assessment of progress and tailoring of therapy to their individual patient’s performance, according to MindMaze. Additionally, it enables the patients to see their progress as well. The set-up and calibration can be done in less than 5 minutes, so patients can begin rehabilitation sessions while physicians facilitate case management.
The program is equipped with a variety of gamified engaging activities which cover motor and task functions and includes a 3D virtual environment. As a result, early findings have suggested that both patient engagement and adherence to therapy have been amplified. Thus far, MindMotion GO has been trialed with upward of 300 patients across therapy centers in the UK, Italy, Germany, and Switzerland.
Neurological impairments are the main cause of long-term disability in the United States, with a recent study estimating direct and indirect costs associated with neurological diseases cost roughly $800 billion annually. For stroke alone, there are almost 800,000 cases each year, with direct annual costs estimated at $22.8 billion.
MindMaze’s Continuum of Care seeks to support earlier, and ongoing, intervention to enable by healthcare providers in the United States to have access to a cost-effective solution for improving neurorehabilitation results.
Even more resources pertaining to stroke prevention and care can be found on MD Magazine‘s new sister site, NeurologyLive.
[Abstract] A Portable Passive Rehabilitation Robot for Upper-Extremity Functional Resistance Training
[Abstract] A portable and cost-effective upper extremity rehabilitation system for individuals with upper limb motor deficits
This paper presents a portable, assistive, soft robotic glove designed to augment hand rehabilitation for individuals with functional grasp pathologies. The robotic glove utilizes soft actuators consisting of molded elastomeric chambers with fiber reinforcements that induce specific bending, twisting and extending trajectories under fluid pressurization. These soft actuators were mechanically programmed to match and support the range of motion of individual fingers. They demonstrated the ability to generate significant force when pressurized and exhibited low impedance when un-actuated. To operate the soft robotic glove, a control hardware system was designed and included fluidic pressure sensors in line with the hydraulic actuators and a closed-loop controller to regulate the pressure. Demonstrations with the complete system were performed to evaluate the ability of the soft robotic glove to carry out gross and precise functional grasping. Compared to existing devices, the soft robotic glove has the potential to increase user freedom and independence through its portable waist belt pack and open palm design.