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Coffee and Stroke

A Swedish study published in the March 10, 2011 edition of Stroke claims that regular coffee consumption can reduce risk of stroke in women by up to 25%.

“Results from our study in women showed that consumption of 1 to 5 cups of coffee per day was associated with a 22 to 25 percent lower risk of stroke, compared with consumption of less than 1 cup a day,” – Susanna Larsson, lead researcher, National Institute of Environmental Medicine, Karolinska Institute in Stockholm

Larsson added that although positive, these are early findings and should not cause women to change their coffee-drinking habits.

The study was large, based on data from 34,670 women, aged 49 to 83, who took part in the Swedish Mammography Cohort, which looked for associations between diet, lifestyle and disease.

It’s Not All Roses

In a study released in the November 2, 2010 edition of Neurology, it was reported that coffee consumption increases the risk of ischemic stroke onset immediately after ingestion. The effect is magnified particularly among infrequent drinkers.

The study, led by Elizabeth Mostofsky, MPH, from Harvard Medical School in Boston, Massachusetts, provides new information that may be useful in stroke prevention and is in line with what is already known about the physiologic effects of coffee.

Mostofsky found that risk of stroke increased two-fold in the hour after drinking a cup of coffee. The increased risk returned to baseline within a 2-hour window, which investigators say strengthens the possibility of a causal relationship. The effect was most pronounced in those that consumed, on average, fewer than one cup of coffee per day. The risk of stroke in those that consume more than one cup per day was substantially less than that in infrequent drinkers.

Researchers have suggested that the increase is likely linked to the effect caffeine has on the body, including rapidly increasing epinephrine release, blood pressure, and insulin sensitivity.

Effect of Caffeine on the Body

Caffeine has systemic effects on the body. These include the following on the circulatory system:

  1. stimulated heart, respiratory and central nervous system
  2. increase in level of fatty acids in the blood which increases its viscosity
  3. raises blood pressure

Cola and Tea

Interestingly, the study showed that tea actually slightly reduces the incidence of stroke in the same period. Cola was shown to have no effect. The researchers speculated this was because neither beverage contained caffeine levels as high as that found in coffee.

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Walking After Stroke

Body-weight supported treadmill therapy and home-based strength and balance therapy yield similar results for patients one year after having stroke, according to a new study released at the 2011 American Stroke Association’s International Stroke Conference.

The study showed the 52% of people who participated in either home-based progressive strength and balance exercises or a clinic-based body-weight supported treadmill demonstrated functional improvement in walking. The Locomotor Experience Applied Post-stroke (LEAPS) trial involved 408 participants who recently suffered stroke.

The investigators has hypothesized that the body-weight supported treadmill program would be superior to a home exercise program. One-year post stroke, however, the gains in walking speed, balance, and quality of life were similar in both groups.

In both groups, the largest functional gains were made during the first 12 sessions of therapy. 13% of subjects continued to improved after the first 12 sessions, but only 7% improved after between sessions 30 to 36.

A secondary finding of the study shows that at six months post-stroke, a group who had not yet received any therapy beyond usual care showed improved walking speed, but only about half as much as the participants who received either the weight-supported walking or home-based program at two months.

According to the researchers, the findings suggest that both home-based and weight support programs are effective forms of physical therapy and are superior to usual care provided according to current standards of practice.

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Stroke Rates Increase in Young People

Alarming figures showing an upward trend in stroke-related hospitalizations of young people were released at the American Stroke Association conference in Los Angeles.

The study, prepared by the US Centers for Disease Control and Prevention, comparing figures from 1994 and 1995 with those in 2006 and 2007 break down stroke hospitalizations by age. The figures are as follows:

  • 51% increase in stroke-related hospitalizations for men under the age of 35
  • 17% increase in stroke-related hospitalizations for women under the age of 35

A 2010 report from Canada indicated similar trends. These figures, published in the Canadian Heart and Stroke Foundation’s 2010 annual report, compared 1994 and 2005, and are as follows:

  • 77% increase in high blood pressure
  • 45% increase in diabetes
  • 18% increase in obesity
  • 250,000 Canadians in their 20s and 30s had high blood pressure in 2005
  • 127% increase in high blood pressure in people aged 35-49

Meanwhile, the American study showed some positive news as well – an opposite trend appeared in older people.

  • 25% decrease in stroke-related hospitalizations for men 65 and older
  • 28% decrease in stroke-related hospitalizations for women 65 and older

The study suggests that better prevention and treatment of conditions such as high blood pressure in older people may be contributing to the decline.

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Stroke and Medicare – Study

A recent study, published in the December 16, 2010 issue of Stroke, close to 2/3 medicare patients discharged from the hospital after suffering an ischemic stroke are readmitted, or die, within a year. The study also found that such post-discharge mortality and rehospitalization rates varied considerably between hospitals. The study showed that such variance was not dependent on the size of the institution or the size of its stroke center designation.

“The very high rates of death and rehospitalization are in a sense staggering, and despite some advances, stroke continues to place a burden on this patient population, which is fee-for-service Medicare beneficiaries. Also striking is the very substantial variation in clinical outcomes by hospitals.” – Dr Gregg Fonarow, Lead Author of the study, UCKA

The following lists some important details of the stroke treatment study:

  • Study based on data from 91,134 Medicare beneficiaries between April 1, 2003 and December 31, 2006
  • Median Age: 79.3 years
  • Overall rate of death or rehospitalization within 12 months: 61.9%
  • Difference in 30-day post-stroke mortality between 2003 and 2006: 0.1% (14.1% in 2003 vs. 14.2% in 2006)
  • Academic hospitals performed marginally better than their nonacademic equivalents (variation of 2%-5%)
  • Significant mortality and readmission variation between hospitals was discovered

Dr. Fonarow was unable to offer insight into why there was such great variance in outcomes between different hospitals

“Understanding what it is about what they’re doing is an important next step. It wasn’t something as simple as where the hospital was located or the number of beds they had; it was more around the processes they had and the systems they had in place, and those were variables we didn’t have access to in this study.”

The authors suggest that several areas of potential improvement exist in post-acute stroke care. These include:

  • stroke severity measurements only documented in 37% of patients – possibly due to the the fact that they arrived by private transport rather than through emergency medical services
  • more than half of the rehospitalizations were related to noncardiovascular causes, which leaves room for significant secondary prevention efforts
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Foot Drop – Denmark Research Prize

The 2010 Danish Research Result of the Year prize has been awarded to Professor Ole Kaeseler Anderson, of the Center for Sensory-Motor Interaction. Anderson and his team has developed a method that uses a stroke patient’s residual spinal reflex reaction to aid in rehabilitation and treatment of foot-drop.

Foot Drop is the inability, or reduced ability, to move the ankle and toes upward (called dorsiflexion). It is usually the result of stroke or other disease of the nervous system. Sufferers often compensate with an exaggerated lift or “swagger” of the leg during walking, or with the help of an ankle-foot orthosis (AFO) that locks the foot in a neutral position. Two FES (Functional Electrical Stimulation) systems have hit the market recently: the Bioness L300 and the Innovative Neurotronics Walkaide. These, and other systems like them, can be very beneficial to suitable patients. Below is a video of the before and after of a patient using the Walkaide system.

Andersen’s research takes advantage of a reflex (controlled by the spinal cord, and not the brain) response to sudden pain. The “nociceptive withdrawal reflex” causes the foot to flex back in response to sudden pain.

“We have developed a method of using electrical stimulation of the withdrawal reflex in a way that can help in patients’ rehabilitation,” says Andersen. “The electrical impulse triggers a natural reflex such that the leg is pulled up and the foot moves, so the patient is helped to move their leg even though he or she was partially paralyzed after a stroke.”

Anderson is not the first to exploit this reflex – in 1993, Granat et al. attempted to improve hip flexion for the wing phase of gait with only limited success. The group cited the following issues:

  • a decrease in the magnitude of the hip flexion to repeated stimuli (habituation)
  • long latency in response
  • inhibition of the response when stimulated bilaterally

Source: Granat MH, Heller BW, Nicol DJ, Baxendale RH, and Andrews BJ. Improving limb flexion in FES gait using the flexion withdrawal response for the spinal cord injured person. Journal of Biomedical Engineering 15: 51-56, 1993.

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Stroke Therapy Study

News of a second stroke rehabilitation study in Southampton was released today (click here for news about another recent stroke rehabilitation study in Southampton). This new study, lead by Dr. Jane Burridge, will combine transcranial Direct Current Stimulation (tDCS) with robotic training for the hand and arm.

tDCS uses a low constant current delivered to the part of the brain of interest using small electrodes. It has been discovered that such a current can result in cortical modulations (modified brain activity) that lasts longer than the current itself. Currently, tDCS is primarily used in applications involving psychological disorders, like anxiety and depression, and is used experimentally in motor rehabilitation.

tDCS is readily compared to Transcranial Magnetic Stimulation (TMS), which uses high voltage pulses of electricity through coils located close to the head to induce a small electrical charge in a desired region of the brain.

The £80,000 (approximately $126,000USD) study, funded by Wessex Medical Trust, will enroll stroke patients in the following treatment regime:

  • 20 minutes of electrical stimulation to increase the “excitability” of the brain cells, which send the messages to the muscles in the arm.
  • three 20-minute sessions with the robotic arms to build strength and get the arm and hand moving again.

The research team hopes that the combination treatment will speed up recovery by increasing activity of the damaged portion of the brain using tDCS, better preparing it to create new connections during the course of robotic therapy.

If successful, the team hopes to create a version of the tDCS machine for use in home-based stroke therapy.

Another similar clinical trial is wrapping up in Israel, although it uses conventional occupational therapy instead of a robotic system:

The purpose of this study is to determine whether a non-painful, non-invasive, brain-stimulation technique called transcranial direct current stimulation (tDCS) combined with occupational therapy (OT) will improve motor function in patients with chronic stroke.

This study is scheduled to be completed this month (December, 2010).

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Hand/Arm Stimulator Trial in the UK

Dr. Jane Burridge, Professor of restorative neuroscience at Southampton University in the UK, is part of a team building a new hand and arm electrical stimulation system for people who have suffered a stroke. Functional Electrical Stimulation (FES) is commonly used as a rehabilitation tool to help retrain a patient’s nervous system by stimulating nerves that control movement. The Bioness H200 is an example of a commercially available stimulator used for hand rehabilitation. Here’s a video of a stroke patient using the H200:

The new UK stimulation system will help patients with hand and arm movements, providing just enough muscle stimulation to help patients complete a set of movements, like reaching out and grasping a tea cup. The researchers hope that training with such a device will help stroke patients regain use of their arms and hands faster, and more effectively.

The project received £464,231 (approximately $722,000) in funding from the EPSRC (Engineering and Physical Science Research Council), and is designed to complement existing hand arm and shoulder rehabilitation training using virtual reality rehabilitation games.

‘We’re going to be stimulating a number of different muscles to open the hand, as well as to reach the arm forward. And, instead of doing it on a pre-determined, very tightly controlled trajectory, we’re actually going to do it with a free movement, with just minimal support from a sling.’ – Dr. Jane Burridge

The experimental work, starting in March 2011 and scheduled to run for three years, will include an eight-week clinical trial involving up to eight stroke patients.

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Robot-Assisted Therapy in New Jersey

During his presentation at Neuroscience 2010, Dr. Sergei V. Adamovich’s suggested that stroke rehabilitation involving video-gaming in combination with a robotic system could improve a patient’s abilities.

“In virtual environments, individuals with arm and hand impairment practiced tasks such as reaching and touching virtual objects. They took a cup from a shelf and put it on a table, hammered a nail, and even played a virtual piano.” – Dr. Adamovich, New Jersey Institute of Technology

The study’s 24 subjects, who had suffered a stroke at least six months prior to therapy, played with the video game system for about 22 hours over a two-week period. The subjects were helped by a robotic arm, and were challenged to perform increasingly difficult tasks.

“Our preliminary data suggest that, indeed, robot-assisted training in virtual reality may be beneficial for functional recovery after chronic stroke. Furthermore, our data imply that this recovery may be particularly due to increased functional connections between different brain regions.” – Dr. Adamovich

The following is a video of Dr. Adamovich’s robotic system.

Sources: Science Daily, RAVR Lab

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New EMG-Controlled Hand Rehabilitation Robot

Tommy Chan at Deltason, a Hong Kong medical devices distributor with an impressive array of rehabilitation products, has recently added the “Hand Of Hope” to his company’s line.

Hand Of Hope

Hand Of Hope

Developed at the Hong Kong Polytechnic University, the Hand Of Hope combines non-invasive EMG sensors with a robotic exo-skeleton to help the patients perform tasks related to rehabilitation. The device is controlled by non-invasive EMG pickup electrodes that detect patients’ attempts to move their hands. Once an attempted movement is detected, linear actuators are used to drive each finger. The system is used to increase performance of hand grasp (palmar grasp and pinch) and hand opening. The range of motion of each finger actuator can be customized for each patient.

Hand Of Hope

Hand Of Hope - Prototype

Hand Of Hope

Hand Of Hope - Prototype

Here are some pictures of the device:

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Large Portion of Post-Stroke Therapy Not Based On Clinical Studies

An alarming study published in Implementation Science in October 2010 suggests that the rate of reliance on the research literature in clinical decision making among physical therapists is low. Simply put, a large portion (more than 50%) of physical therapists surveyed in the study rarely base their post-stroke treatment programs on evidence-based research studies.

The study identified organizational, research, and practitioner characteristics associated with research use among physical therapists involved in post-stroke rehabilitation services. Of 263 physical therapists surveyed, more than a third hardly used evidence-based research at all (no more than once per month), with more than 50% only referring to evidence-based research 2-5 times per month.

The author summarizes the need important of evidence-based medicine in the following paragraph:

Evidence-based medicine has been described as ‘the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients. Numerous perceived benefits of evidence-based practice (EBP), including improvement to the work environment, increased professional accountability, ensuring the future of the profession, improved efficiency of service delivery, and compliance with regulatory agencies or quality assurance initiatives in the workplace, may lead healthcare professionals to incorporate research evidence into clinical practice. A patient-centered motivation for appropriately applying findings from rigorously conducted research in clinical decision making is to improve the quality of healthcare services and patient outcomes. There is empirical evidence to support these latter benefits in post-acute stroke rehabilitation, wherein the degree of compliance with a clinical practice guideline has been associated with not only physical recovery but also patient satisfaction.

The authors’ study was primarily based on data collected in Canada, but cited the following statistics gathered from similar studies conducted in other parts of the world:

Location PTs Surveyed 0-1 times/month 2-5 times/month
USA 488 25% 49%
Australia 124 43.9% unknown
Canada (this study) 263 33.8% 52.9%
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