News Article | September 29, 2016
A meta-analysis has found that the administration of a clot-removal device via the arteries and the use of medical therapy are less likely to result in disability three months after a stroke compared to medical therapy alone. In a study, published in The Journal of the American Medical Association, Jeffrey Saver and colleagues analyzed five randomized trials. They were able to show that the combination approach offered by second-generation endovascular recanalization treatments are more beneficial than medical therapy alone for acute ischemic stroke patients with blockages in their large vessels. It wasn't clear, however, if the combination therapy would still show benefit when administered more than six hours after symptoms were observed. After comparing data from 1,287 patients from across 89 sites in international locations, taking into consideration clinical, demographic and brain imaging information, as well as radiologic and functional outcomes, the researchers found that endovascular thrombectomy (the use of a micro-catheter or other clot-removal device intra-arterially) and medical therapy (the use of a clot-dissolving agent) were associated with less-severe disability at three months, especially when treatment was provided within two hours of symptom onset. The combination treatment still offered benefit when administered after two hours of symptom onset, but only until 7.3 hours. Beyond that, the treatment's effects became insignificant. There were 390 patients who experienced substantial blood flow restoration after receiving endovascular thrombectomy, but the researchers observed that for every hour that the procedure was delayed, chances of less functional independence and more severe disability increases although mortality rates remained the same. Based on their findings, the researchers want to emphasize how important it is to raise patient awareness and promote in-hospital management and out-of-hospital care to reduce the delay between symptom onset and treatment administration. Earlier in September, researchers from the Case Western Reserve University, the Cleveland Functional Electrical Stimulation Center and the MetroHealth System showed that a new electrical stimulation therapy improved hand dexterity in stroke survivors. Their work also demonstrated that self-administered home therapy can be effective. Each year, about 800,000 people in the U.S. experience strokes, but another study has found that nine out of 10 cases are actually preventable, if only people took the time to take care of themselves. For instance, addressing high blood pressure, a leading risk factor, can lead to an almost 48-percent drop in the likelihood of experiencing a stroke. Other risk factors like physical inactivity, lipid levels, poor eating habits and obesity led to 48-, 27-, 23- and 19-percent drops in stroke risk when addressed. © 2017 Tech Times, All rights reserved. Do not reproduce without permission.
News Article | September 14, 2016
A new electrical stimulation therapy improved hand dexterity for stroke survivors more than an existing technique, in a study released today. Strokes, which strike about in 800,000 people in the United States each year, usually result in some degree of paralysis on one side of the body that can make it hard for survivors to open a hand. A common therapy in stroke rehabilitation uses low levels of electric current to stimulate paralyzed muscles to open the hand, improve muscle strength and possibly restore hand function. A therapist sets stimulation intensity, cycle timing and repetitions. In the new experimental therapy developed by researchers at the MetroHealth System, Case Western Reserve University and the Cleveland Functional Electrical Stimulation Center, patients control the stimulation to their weak hand by wearing a glove with sensors on the opposite, unaffected hand. When patients open their unaffected hand, they receive a corresponding amount of stimulation that opens their weak stroke-affected hand. This puts patients back in control of their hand and enables them to participate in therapy with the assistance of electrical stimulation. For the study, 40 stroke survivors received therapy using the new glove for 12 weeks and 40 received the common therapy. Both groups used an electrical stimulator on their own at home for 10 hours a week, plus 3 hours per week practicing hand tasks with an occupational therapist in the lab. Hand function was measured before and after therapy with a standard dexterity test that determined the number of blocks participants can pick up, lift over a barrier and release in another area on a table within 60 seconds. Researchers plan to perform a multi-site study to confirm their results, as well as measure quality of life improvements for patients. While the researchers speculate that the new therapy may be changing neural connections in the brain that control hand dexterity, additional studies are needed to determine what effects it may have on the central nervous system. The study also demonstrates that stroke patients can effectively use technology for self-administered therapy at home, said Jayme S. Knutson, Ph.D., an assistant professor of physical medicine and rehabilitation at Case Western Reserve University School of Medicine in Cleveland, Ohio. “Home-based therapy is becoming increasingly important to offset increasing healthcare costs and to meet the need for high doses of therapy that are critical for attaining the best outcomes,” he said. “The more therapy a patient can get, the better potential outcome they will get.” The study is published in in the American Heart Association journal Stroke.
Makowski N.,Case Western Reserve University |
Makowski N.,Cleveland Functional Electrical Stimulation Center |
Knutson J.,Case Western Reserve University |
Knutson J.,Cleveland Functional Electrical Stimulation Center |
And 6 more authors.
Journal of Rehabilitation Research and Development | Year: 2013
Functional electrical stimulation (FES) may be able to augment functional arm and hand movement after stroke. Post stroke neuroprostheses that incorporate voluntary effort and FES to produce the desired movement must consider how forces generated by voluntary effort and FES combine, even in the same muscle, in order to provide an appropriate level of stimulation to elicit the desired assistive force. The goal of this study was to determine whether the force produced by voluntary effort and FES add together independently of effort or whether the increment in force depends on the level of voluntary effort. Isometric force matching tasks were performed under different combinations of voluntary effort and FES. Participants reached a steady level of force, and while attempting to maintain a constant effort level, FES was applied to augment the force. Results indicate that the increment in force produced by FES decreases as the level of initial voluntary effort increases. Potential mechanisms causing the change in force output are proposed, but the relative contribution of each mechanism is unknown.
Mariano T.Y.,Case Western Reserve University |
Mariano T.Y.,Cleveland Functional Electrical Stimulation Center |
Bhadra N.,Case Western Reserve University |
Bhadra N.,Cleveland Functional Electrical Stimulation Center |
And 2 more authors.
Neurourology and Urodynamics | Year: 2010
Aims: Reflex contractions of the external urethral sphincter (EUS) are a major component of voiding dysfunctionafter neurological injury or disease. Aberrant urethral reflexes can prevent voiding and cause serious medicalcomplications. Characterizing these urethral reflexes during genitourinary studies is necessary for evaluating novelpharmacological or neuroprosthetic approaches. The objectives of the present study were to generate urethralreflexes in the acute spinal feline, to quantify these reflexes, and to suppress them with electrical stimulation of thesacral dermatomes. Methods: This study comprised eight male cats. Anaesthesia was maintained with alphachloraloseor sodium pentobarbital. The spinal cord was transected between T10 and T12, and nerve cuff electrodeswere placed on the extradural S2 sacral roots to provide bladder activation. Bladder and urethral pressures wererecorded during and after bladder contractions. Electrical stimulation was applied non-invasively to the sacraldermatomes with commercial surface electrodes. Results: Urethral reflexes were elicited consistently in six cats.The corresponding urethral pressure spikes were quantified. Putative metrics of urethral reflex activity such as therate and average magnitude of reflex pressure spikes correlated significantly with standard urodynamic variables.Electrical stimulation of the sacral dermatomes suppressed urethral reflexes in three cats. Conclusions: Thesefindings in an acute spinal feline preparation demonstrate a non-invasive means of suppressing undesirableurethral reflexes. Translation of this work to clinical use could improve neuroprostheses for restoring bladderfunction and enhance treatment of aberrant urethral reflexes in humans. Neurourol. Urodynam. 29:494-500,2010. Copyright © 2009 Wiley-Liss, Inc.
Crago P.E.,Case Western Reserve University |
Crago P.E.,Cleveland Functional Electrical Stimulation Center |
Makowski N.S.,Case Western Reserve University |
Makowski N.S.,Cleveland Functional Electrical Stimulation Center
Journal of Neural Engineering | Year: 2014
Objective. Stimulation of peripheral nerves is often superimposed on ongoing motor and sensory activity in the same axons, without a quantitative model of the net action potential train at the axon endpoint. Approach. We develop a model of action potential patterns elicited by superimposing constant frequency axonal stimulation on the action potentials arriving from a physiologically activated neural source. The model includes interactions due to collision block, resetting of the neural impulse generator, and the refractory period of the axon at the point of stimulation. Main results. Both the mean endpoint firing rate and the probability distribution of the action potential firing periods depend strongly on the relative firing rates of the two sources and the intersite conduction time between them. When the stimulus rate exceeds the neural rate, neural action potentials do not reach the endpoint and the rate of endpoint action potentials is the same as the stimulus rate, regardless of the intersite conduction time. However, when the stimulus rate is less than the neural rate, and the intersite conduction time is short, the two rates partially sum. Increases in stimulus rate produce non-monotonic increases in endpoint rate and continuously increasing block of neurally generated action potentials. Rate summation is reduced and more neural action potentials are blocked as the intersite conduction time increases. At long intersite conduction times, the endpoint rate simplifies to being the maximum of either the neural or the stimulus rate. Significance. This study highlights the potential of increasing the endpoint action potential rate and preserving neural information transmission by low rate stimulation with short intersite conduction times. Intersite conduction times can be decreased with proximal stimulation sites for muscles and distal stimulation sites for sensory endings. The model provides a basis for optimizing experiments and designing neuroprosthetic interventions involving motor or sensory stimulation. © 2014 IOP Publishing Ltd.
Makowski N.S.,Case Western Reserve University |
Makowski N.S.,Cleveland Functional Electrical Stimulation Center |
Knutson J.S.,Case Western Reserve University |
Knutson J.S.,Cleveland Functional Electrical Stimulation Center |
And 6 more authors.
Neurorehabilitation and Neural Repair | Year: 2014
Background. Hemiparesis after stroke can severely limit an individual's ability to perform activities of daily living. Functional electrical stimulation (FES) has the potential to generate functional arm and hand movements. We have observed that FES can produce functional hand opening when a stroke patient is relaxed, but the FES-produced hand opening is often overpowered by finger flexor coactivation in response to patient attempts to reach and open the hand. Objective. To determine if stimulating both reaching muscles and hand opening muscles makes it possible to achieve useful amounts of simultaneous reach and hand opening even in the presence of submaximal reaching effort. Methods. We measured reach and hand opening during a reach-then-open the hand task under different combinations of voluntary effort and FES for both reach and hand opening. Results. As effort was reduced and stimulation generated more movement, a greater amount of reach and hand opening was achieved. For the first time, this study quantified the effect of voluntary effort for reach and hand opening on stimulated hand opening. It also showed variability in the interaction of voluntary effort and stimulation between participants. Additionally, when participants were instructed to reach with partial effort during simultaneous FES, they achieved greater reach and hand opening. Conclusions. Simultaneous reaching and FES hand opening is improved by including FES for reach and reducing voluntary effort. In the future, an upper extremity neuroprosthesis that uses a combination of voluntary effort and FES assistance may enable users to perform activities of daily living. © The Author(s) 2013.
Liao J.Y.,Case Western Reserve University |
Liao J.Y.,Cleveland Functional Electrical Stimulation Center |
Kirsch R.F.,Case Western Reserve University |
Kirsch R.F.,Cleveland Functional Electrical Stimulation Center
PLoS ONE | Year: 2014
We have demonstrated that 3D target-oriented human arm reaches can be represented as linear combinations of discrete submovements, where the submovements are a set of minimum-jerk basis functions for the reaches. We have also demonstrated the ability of deterministic feed-forward Artificial Neural Networks (ANNs) to predict the parameters of the submovements. ANNs were trained using kinematic data obtained experimentally from five human participants making target-directed movements that were decomposed offline into minimum-jerk submovements using an optimization algorithm. Under cross-validation, the ANNs were able to accurately predict the parameters (initiation-time, amplitude, and duration) of the individual submovements. We also demonstrated that the ANNs can together form a closed-loop model of human reaching capable of predicting 3D trajectories with VAF >95.9% and RMSE ≤4.32 cm relative to the actual recorded trajectories. This closed-loop model is a step towards a practical arm trajectory generator based on submovements, and should be useful for the development of future arm prosthetic devices that are controlled by brain computer interfaces or other user interfaces. © 2014 Liao, Kirsch.
News Article | September 9, 2016
Stroke survivors showed improved hand dexterity more when using a new electrical stimulation therapy compared to an existing stimulation technique, said researchers from the MetroHealth System, Cleveland Functional Electrical Stimulation Center and the Case Western Reserve University. Every year, some 800,000 individuals experience strokes in the U.S. The medical condition is characterized by reduced blood flow to the brain and usually results in paralysis or partial paralysis on one side of the body, making it difficult for survivors to open a hand. To address this, low-level electric currents are applied to the affected hand to stimulate paralyzed muscles, with intensity, repetitions and timing set by therapists. For a study published in the journal Stroke, the researchers developed a new electrical stimulation therapy that involved stroke survivors wearing a glove with sensors on their unaffected hand to control stimulation applied to their weak hand. As the unaffected hand is opened, a corresponding level of stimulation is applied to the weak hand, opening it. Positive results from earlier studies carried out by the researchers encouraged them to compare the electrical stimulation therapy they developed with what's commonly used to rehabilitate stroke survivors. Specifically, they wanted to determine which one is more effective for patients who are over six months past their stroke. For the study, the researchers worked with 80 stroke survivors, half of which were administered the new electrical stimulation therapy and the other half provided with the common therapy. Hand function in all the subjects were also assessed before and after the therapy with a standard dexterity test involving moving blocks across a barrier within 60 seconds. Based on their findings, the researchers saw that those who were on the receiving end of the new electrical stimulation therapy had better dexterity test scores (4.6 blocks) compared to the group that was given the common therapy (1.8 blocks). Additionally, those with no finger movement in the new therapy group prior to the study showed arm movement improvements. At the end of the study, 97 percent of subjects from the new therapy group said that they have better usage in their affected hand than before the experiment began. Aside from registering better treatment results, the study was also able to demonstrate that self-administered home therapy can be effective for stroke survivors. "The more therapy a patient can get the better potential outcome they will get," said Jayme Knutson, Ph.D., the study's senior author. Knutson is joined by John Chae, M.D., Richard Wilson, M.D. and Douglas Gunzler, Ph.D. in the study. For their next step, the researchers are looking at carrying out a multi-site study not only to confirm results from the study but also to measure improvements in quality of life experienced by stroke survivors using the new electrical stimulation method. © 2017 Tech Times, All rights reserved. Do not reproduce without permission.
Knutson J.S.,Cleveland Functional Electrical Stimulation Center
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference | Year: 2012
Contralaterally controlled functional electrical stimulation (CCFES) is an innovative method of delivering neuromuscular electrical stimulation for rehabilitation of paretic limbs after stroke. It is being studied to evaluate its efficacy in improving recovery of arm and hand function and ankle dorsiflexion in chronic and subacute stroke patients. The initial studies provide preliminary evidence supporting the efficacy of CCFES.
Williams M.R.,Cleveland Functional Electrical Stimulation Center |
Walter W.,Rochester Institute of Technology
PLoS ONE | Year: 2015
The loss of a hand can greatly affect quality of life. A prosthetic device that can mimic normal hand function is very important to physical and mental recuperation after hand amputation, but the currently available prosthetics do not fully meet the needs of the amputee community. Most prosthetic hands are not dexterous enough to grasp a variety of shaped objects, and those that are tend to be heavy, leading to discomfort while wearing the device. In order to attempt to better simulate human hand function, a dexterous hand was developed that uses an over-actuated mechanism to form grasp shape using intrinsic joint mounted motors in addition to a finger tendon to produce large flexion force for a tight grip. This novel actuation method allows the hand to use small actuators for grip shape formation, and the tendon to produce high grip strength. The hand was capable of producing fingertip flexion force suitable for most activities of daily living. In addition, it was able to produce a range of grasp shapes with natural, independent finger motion, and appearance similar to that of a human hand. The hand also had a mass distribution more similar to a natural forearm and hand compared to contemporary prosthetics due to the more proximal location of the heavier components of the system. This paper describes the design of the hand and controller, as well as the test results.