[WEB SITE] Researchers building glove to treat symptoms of stroke

by Stanford University Medical Center

A new glove being developed by Georgia Tech and Stanford researchers aims to treat symptoms of stroke through vibration. Credit: Caitlyn Seim

Strokes often have a devastating impact on hands function. Now, Stanford researchers are collaborating on a vibrating glove that could improve hand function after a stroke.

The most obvious sign someone has survived a stroke is usually some trouble speaking or walking. But another challenge may have an even greater impact on someone’s daily life: Often, stroke survivors lose sensation and muscle control in one arm and hand, making it difficult to dress and feed themselves or handle everyday objects such as a toothbrush or door handle.

Now, researchers at Stanford are working on a novel therapy that could help more stroke survivors regain the ability to control their arms and hands—a vibrating glove that gently stimulates the wearer’s hand for several hours a day.

Caitlyn Seim, Ph.D., a postdoctoral scholar at Stanford, began the project as a graduate student in human-centered computing at Georgia Tech in the hope that the glove’s stimulation could have some of the same impact as more traditional exercise programs. After developing a prototype, she approached Stanford colleagues Maarten Lansberg, MD, Ph.D., an associate professor of neurology, and Allison Okamura, Ph.D., a professor of mechanical engineering, in order to expand her efforts. With help from a Neuroscience:Translate grant from the Wu Tsai Neurosciences Institute at Stanford, the trio are working to improve on their prototype glove and bring the device closer to clinical testing.

“The concept behind it is that users wear the glove for a few hours each day during normal daily life—going to the supermarket or reading a book at home,” Seim said. “We are hoping that we can discover something that really helps stroke survivors.”

Reaching for new stroke treatments

Seim, Lansberg and Okamura’s goal is a tall order. Despite some individual success stories, the reality is that most stroke patients struggle to regain the ability to speak, move around and take good care of themselves.

“Stroke can affect patients in many ways, including causing problems with arm function, gait, vision, speech and cognition,” Lansberg said. Yet despite decades of research, “there are essentially no treatments that have been proven to help stroke patients recover these functions,” he added.

It was in that context that the three researchers independently started thinking about what they could do to improve the lives of people who have survived strokes. As the medical doctor in the bunch, Lansberg had already been treating stroke patients for years and has helped lead the Stanford Stroke Collaborative Action Network, or SCAN, another project of the Wu Tsai Neurosciences Institute. Okamura, meanwhile, has focused much of her research on haptic, or touch-based, devices, and in the last few years her lab has spent more and more time thinking about how to use those devices to help stroke survivors.

“Rehabilitation engineering provides a unique opportunity for me to work directly with the patients who are affected by our research,” Okamura said. “The potential to translate the kind of technology relatively quickly to a commercial product that can reach a large number of stroke patients in need of therapy is also very exciting.”

For her part, Seim’s interest in stroke stems from an interest in wearable computing devices. Yet rather than build more virtual-reality goggles and smartwatches, Seim said she wants to apply wearable computing to the areas of health and accessibility—”areas which have some of the most compelling problems to me.”

Growing a new idea

With that ambition in mind, Seim built a vibrating glove prototype that she hoped would stimulate nerves and improve both sensation and function in stroke survivors’ hands and arms. After collecting some promising initial data, Seim reached out to the Stanford team.

“Stanford has SCAN and StrokeNet, along with a community of interdisciplinary engineering and computing research, so I reached out to Maarten, and he was very supportive,” Seim said.

Now, Seim, Lansberg and Okamura are revising the glove’s design to improve its function and to add elements for comfort and accessibility. Then, they’ll begin a new round of clinical tests at Stanford.

Long term, the hope is to build something that helps stroke survivors recover some of the functions they have lost in their hands and arms. And if initial tests work out, Lansberg said, it’s possible the same basic idea could be applied to treat other complications associated with stroke.

“The glove is an innovative idea that has shown some promise in pilot studies,” Lansberg said. “If proven beneficial for patients with impaired arm function, it is conceivable that variations of this type of therapy could be developed to treat, for example, patients with impaired gait.”

 

via Researchers building glove to treat symptoms of stroke

[ARTICLE] A pilot study into reaching performance after severe to moderate stroke using upper arm support – Full Text

Abstract

Stroke effects millions of people each year and can have a significant impact on the ability to use the impaired arm and hand. One of the results of stroke is the development of an abnormal shoulder-elbow flexion synergy, where lifting the arm can cause the elbow, wrist, and finger flexors to involuntarily contract, reducing the ability to reach with the arm and hand opening. This study explored the effect of using support at the upper arm to improve hand and arm reaching performance. Nine participants were studied while performing a virtual reaching task under three conditions: while the weight of their impaired arm was supported by a robot arm, while unsupported, and while using their non-impaired arm. Most subjects exhibited faster and more accurate reaching while supported compared to unsupported. For the subjects who could voluntarily open their hand, most were able to more swiftly open their hand when using upper arm support. In many cases, performance with support was not statistically different than the unaffected arm and hand. Muscle activity of the impaired limb with upper arm support showed decreased effort to lift the arm and reduced biceps activity in most subjects, pointing to a reduction in the abnormal flexion synergy while using upper arm support. While arm support can help to reduce the activation of abnormal synergies, weakness resulting from hemiparesis remains an issue impacting performance. Future systems will need to address both of these causes of disability to more fully restore function after stroke.

Introduction

Stroke is a common occurrence in the U.S.; Approximately 795,000 Americans suffer a stroke every year [1]. It is the third leading cause of death and one of the main causes of disability. There are currently 7,000,000 chronic stroke survivors over 20 years old in the U.S., representing about 3% of the general population [1]. In the veteran community, over 5,000 veterans are hospitalized each year due to ischemic stroke, with those patients accounting for over 10% of the case load and costing more than three times the overall average [2]. Recent studies have shown that there is a significantly increased risk of stroke in people who have suffered traumatic brain injuries (TBIs) [3,4] and in patients with Post Traumatic Stress Disorder (PTSD) who are often on potent antipsychotic medications [5]. With these conditions being seen in remarkably greater numbers in the current military engagements compared to previous combat actions, there exists the likelihood of the VA seeing progressively more stroke survivors [6,7].

There are many potential effects of a stroke, depending on where in the brain the event occurred. Approximately 50% of stroke survivors over age 64 have some hemiparesis affecting control of the arm and hand [1] with the vast majority (88.4%) not regaining complete function [8]. Moderate to severe hemiparesis can have a significant impact upon many common activities of daily living (ADLs), resulting in significant dependence on caregivers. In particular, upper limb hemiparesis, which occurs in approximately 26% of stroke survivors [1], negatively impacts bimanual tasks, such as opening containers, cutting food, and holding open a bag such as a wallet or grocery bag. In addition to hemiparesis, stroke survivors can also develop abnormal muscle synergies where voluntary effort to contract the muscle or group of muscles needed to execute a task causes other muscles not normally involved in the task to involuntarily contract, resulting in loss of control or coordination during certain movements [9–14].

One common abnormal synergy is the shoulder-elbow flexion synergy where the elbow, wrist, and fingers flex involuntarily when the patient abducts or raises the shoulder–resulting in a loss of reach area and difficulty performing ADLs. The magnitude of this effect is related to the amount of effort the individual exerts. Abnormal synergy does not occur if the arm is manually lifted by an outside force (e.g. by a therapist or assistive device). However, when the individual lifts their arm voluntarily, the synergy is activated, with increasing amounts of shoulder abduction torque resulting in greater elbow, wrist, and finger flexion torque, which reduces the overall reach volume of the arm [9,12].

In studies of individuals with stroke, providing gravity compensation at the forearm has allowed participants to access a greater range of motion. In the case of stroke this is the result of reducing abnormal muscle synergies [9,15], and allowing for retained voluntary control to be more effective.

One way to provide this type of support is to use a mechanical assistance device. Over the years, a number of robots intended for post-stroke rehabilitation of the upper extremity have been developed for both therapy and to assist daily function. Notable examples of therapy devices include the ARMin [16–18] and RUPERT [19,20]. The MIT MANUS robot has been clinically evaluated and has shown statistically significant although functionally modest results in rehabilitation and motor re-learning [21]. While these previous devices were lab-based robots intended for therapy, a number of robotic devices for assisting arm function as a form of “force prosthesis” have been developed that range from devices to support the arm against gravity [22–26] to full arm, powered exoskeletons [27,28]. The primary drawback to these machines is that due to the force requirements and the kinematics of applying force assistance at the end of the forearm, they tend to be large and are required to be mounted to a user’s wheelchair or other rigid structure [29]. While some stroke patients are limited in terms of walking mobility, a large number are ambulatory and do not require a wheelchair, and hence are not interested in using these large, primarily lab-based mechanical devices to assist in their daily activities. For these users, a different solution is needed.

Thus far, all of the devices in clinical use attempt to reduce abnormal muscle synergy by providing gravity assistance at the forearm, but support at the upper arm, between the shoulder and elbow, has not been explored. This work investigates the hypothesis that upper arm support can assist shoulder abduction by producing gravity compensation for the affected limb and improve reaching capacity.

Methods

To explore the impact of upper arm support on improving reaching and hand opening, research participants were asked to perform directed reaching tasks in a virtual reality environment. This was done over three conditions, 1) with their impaired arm while supported, 2) with the impaired arm without support, and 3) with their unaffected arm as a “gold standard” for comparison.

Participants

For this work, nine people who have suffered a severe to moderate stroke (Table 1) were recruited through the stroke research programs in cooperation with clinicians at the Louis Stokes Cleveland DVA Medical Center (LSCDVAMC). Inclusion criteria consisted of: 1) being greater than 6 months post-stroke, 2) age between 20 and 80 years old, 3) having paresis confined to one side of the body with upper limb motor impairment, and 4) presenting moderate to severe impairment (Fugl-Meyer upper limb assessment between 15 and 47) including a reduced reach volume and reduced voluntary extension of the joints of the affected arm. Criteria for excluding participants was: 1) having substantial pain in the impaired limb, 2) having sensory impairment of the affected limb, 3) having visual deficits beyond those that can be corrected with corrective lenses, 4) being unable to perceive or visually track objects shown on a computer screen, 5) exhibiting cognitive impairment that would preclude the individual from following simple instructions similar to those common to standard of care therapy practices, and 6) having apraxia or significant neglect of the impaired limb. All subjects were able to give written Informed Consent and all research protocols were approved by the Louis Stokes Cleveland Department of Veterans Affairs Medical Center Institutional Review Board, IRB #16050-H37. Prior to any reaching experiments, participants were screened using the Mini Mental State Exam to verify that they were cognitively capable of both providing Informed Consent as well as able to follow basic instructions.

 

Fig 1. Photograph of experimental set-up showing VR display, motion capture camera, arm support, and subject.
The individual in this manuscript has given written informed consent (as outlined in PLOS consent form) to publish these case details.
https://doi.org/10.1371/journal.pone.0200787.g001

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