Posts tagged stroke
Articles and news from the latest research reports.
Scientists report a potential new treatment to prevent strokes
Scientists may have discovered a new way to prevent strokes in high risk patients, according to research from the University of Warwick and University Hospitals Coventry and Warwickshire (UHCW).
Work by a new research group, led by Professor Donald Singer, Professor of Therapeutics at Warwick Medical School and Professor Chris Imray from UHCW, has now been published in US journal Stroke.
The group is using ultrasound scanning to look at patients with carotid artery disease, one of the major causes of stroke. Clots can form on diseased carotid arteries in the neck. Small parts of these clots can released to form microemboli, which can travel to block key brain arteries and lead to weakness, disturbed speech, loss of vision and other serious stroke syndromes. Standard anti-platelet drugs such as aspirin may not prevent the formation of harmful microemboli.
The scanning process can be used to find patients at very high risk of stroke because microemboli have formed despite prior anti-platelet drugs. Using scanning, the team has found that tirofiban, another anti-platelet drug designed to inhibit the formation of blood clots, can suppress microemboli where previous treatment such as aspirin has been ineffective. In their study, tirofiban was more effective than other ‘rescue’ treatment.
Professor Singer said: “These findings show that the choice of rescue medicine is very important when carotid patients develop microemboli despite previous treatment with powerful anti-platelet drugs such as aspirin. We now need to go on to further studies of anti-microemboli rescue treatments, to aim for the right balance between protection and risk for our patients.”
Professor Imray said: “These findings show the importance of ultrasound testing for micro-emboli in carotid disease patients. These biomarkers of high stroke risk cannot be predicted just from assessing the severity of risk factors such as smoking history, cholesterol and blood pressure.”
SMART Arm helps stroke survivors recover faster
A non-robotic device that helps stroke survivors regain upper limb movement is expected to be commercially available in Australia within the next 12 months.
Sensory-Motor Active Rehabilitation Training Arm (SMART Arm) is a device developed by researchers from The University of Queensland and James Cook University.
The device enables stroke survivors with upper limb weakness to drive their own rehabilitation through feedback on performance via an interactive computer program and incremental increases in load and reaching range.
What You Hear Could Depend on What Your Hands are Doing
A new finding could lead to strategies for treating speech loss after a stroke and helping children with dyslexia.
New research links motor skills and perception, specifically as it relates to a second finding—a new understanding of what the left and right brain hemispheres “hear.” Georgetown University Medical Center researchers say these findings may eventually point to strategies to help stroke patients recover their language abilities, and to improve speech recognition in children with dyslexia.
The study, presented at Neuroscience 2012, the annual meeting of the Society for Neuroscience, is the first to match human behavior with left brain/right brain auditory processing tasks. Before this research, neuroimaging tests had hinted at differences in such processing.
“Language is processed mainly in the left hemisphere, and some have suggested that this is because the left hemisphere specializes in analyzing very rapidly changing sounds,” says the study’s senior investigator, Peter E. Turkeltaub, M.D., Ph.D., a neurologist in the Center for Brain Plasticity and Recovery. This newly created center is a joint program of Georgetown University and MedStar National Rehabilitation Network.
Turkeltaub and his team hid rapidly and slowly changing sounds in background noise and asked 24 volunteers to simply indicate whether they heard the sounds by pressing a button.
“We asked the subjects to respond to sounds hidden in background noise,” Turkeltaub explained. “Each subject was told to use his or her right hand to respond during the first 20 sounds, then the left hand for the next 20 second, then right, then left, and so on.”
He says when a subject was using their right hand, they heard the rapidly changing sounds more often than when they used their left hand, and vice versa for the slowly changing sounds.
“Since the left hemisphere controls the right hand and vice versa, these results demonstrate that the two hemispheres specialize in different kinds of sounds—the left hemisphere likes rapidly changing sounds, such as consonants, and the right hemisphere likes slowly changing sounds, such as syllables or intonation,” Turkeltaub explains.
“These results also demonstrate the interaction between motor systems and perception. It’s really pretty amazing. Imagine you’re waving an American flag while listening to one of the presidential candidates. The speech will actually sound slightly different to you depending on whether the flag is in your left hand or your right hand.”
Ultimately, Turkeltaub hopes that understanding the basic organization of auditory systems and how they interact with motor systems will help explain why language resides in the left hemisphere of the brain, and will lead to new treatments for language disorders, like aphasia (language difficulties after stroke or brain injury) or dyslexia.
“If we can understand the basic brain organization for audition, this might ultimately lead to new treatments for people who have speech recognition problems due to stroke or other brain injury. Understanding better the specific roles of the two hemispheres in auditory processing will be a big step in that direction. If we find that people with aphasia, who typically have injuries to the left hemisphere, have difficulty recognizing speech because of problems with low-level auditory perception of rapidly changing sounds, maybe training the specific auditory processing deficits will improve their ability to recognize speech,” Turkeltaub concludes.
(Source: explore.georgetown.edu)
Worldwide patent for a Spanish stroke rehabilitation robot
Robotherapist 3D, a robot which aids stroke patients’ recovery, is to be brought to market by its worldwide patent holder, a spin-off company from the Miguel Hernández University of Elche (Alicante, Spain). It is the first robot to enable patients to start doing exercises while supine, allowing them to begin shortly after the stroke and expediting recovery.
The company, a leader in this field in Spain, already has two robots: Robotherapist 2D and Robotherapist 3D. For the latter, it has a worldwide patent. Both are actuated by pneumatic technology and have been designed to improve arm movement in stroke patients.
According to the researcher, Robotherapist 2D is a planar robot which allows movement in two dimensions and includes sensors to determine the patient’s condition and a sound feedback system. “With this robot, certain tasks are carried out. The patient’s arm is moved parallel to the table: to the right, to the left and in a straight line. They are exercises to improve coordination,” he says.
![Canadian Team Reports World’s First Successful Clinical Trial to Protect the Brain From Damage Caused by Stroke
A team of Canadian scientists and clinicians, led by Dr. Michael Hill of the Calgary Stroke Program at Foothills Medical Centre and University of Calgary’s Hotchkiss Brain Institute (HBI), have demonstrated that a neuroprotectant drug, developed by Dr. Michael Tymianski at the Krembil Neuroscience Centre, located at the Toronto Western Hospital, protects the human brain against the damaging effects of stroke.
The study, “Safety and efficacy of NA-1 for neuroprotection in iatrogenic stroke after endovascular aneurysm repair: a randomized controlled trial,” published online today in The Lancet Neurology, was conducted concurrently with a laboratory study published in Science Translational Medicine, that predicted the benefits of the stroke drug.
This landmark clinical trial was a randomized, double blinded, multi-centre trial that was conducted in Canada and the USA. The study evaluated the effectiveness of NA-1[Tat-NR2B9c] when it was administered after the onset of small strokes that are incurred by patients who undergo neurointerventional procedures to repair brain aneurysms. This type of small ischemic stroke occurs in over 90% of aneurysm patients after such a procedure, but usually does not cause overt neurological disability.](http://40.media.tumblr.com/tumblr_mblbknNMT41rog5d1o1_500.jpg)
Canadian Team Reports World’s First Successful Clinical Trial to Protect the Brain From Damage Caused by Stroke
A team of Canadian scientists and clinicians, led by Dr. Michael Hill of the Calgary Stroke Program at Foothills Medical Centre and University of Calgary’s Hotchkiss Brain Institute (HBI), have demonstrated that a neuroprotectant drug, developed by Dr. Michael Tymianski at the Krembil Neuroscience Centre, located at the Toronto Western Hospital, protects the human brain against the damaging effects of stroke.
The study, “Safety and efficacy of NA-1 for neuroprotection in iatrogenic stroke after endovascular aneurysm repair: a randomized controlled trial,” published online today in The Lancet Neurology, was conducted concurrently with a laboratory study published in Science Translational Medicine, that predicted the benefits of the stroke drug.
This landmark clinical trial was a randomized, double blinded, multi-centre trial that was conducted in Canada and the USA. The study evaluated the effectiveness of NA-1[Tat-NR2B9c] when it was administered after the onset of small strokes that are incurred by patients who undergo neurointerventional procedures to repair brain aneurysms. This type of small ischemic stroke occurs in over 90% of aneurysm patients after such a procedure, but usually does not cause overt neurological disability.
A popular medicine helps repair brain after a stroke – for now, in rats
Strokes often cause loss or impairment of vital brain functions – such as speech, movement, vision or attention. Restoration of these functions is often possible, but difficult. One of the factors impeding brain plasticity is inflammation. A study on rats, carried out at the Nencki Institute in Warsaw, suggests that effectiveness of neurorehabilitation after a stroke can be improved by anti-inflammatory drugs.
Post-stroke inflammation slows down recovery and impairs brain plasticity, reveal the results from the lab of Professor Małgorzata Kossut at the Nencki Institute in Warsaw. The popular anti-inflammatory drug ibuprofen restores the ability of brain cortex to reorganize – a process necessary for recovery of stroke-damaged functions. “Our research was conducted on rats, but we have good reasons to suppose that in future our results will help improve effectiveness of rehabilitation of stroke patients”, says Prof. Kossut.
The Nencki Institute team stresses that so far there are no proofs that the treatment will be effective in humans and that they did not investigate if the ibuprofen therapy prevents strokes, but concentrated on post-stroke recovery.
The most frequent cause of stroke is blocking of brain arteries. Without supply of oxygen, neurons die quckly. In the region of stroke-induced damage pathological changes cause decrease of brain tissue metabolism, impairment of neurotransmission and edema.
Brain control over physiological and voluntary functions may be lost, depending on the localization of the infarct. Impairments of movement, vision, speech and attention are frequent. In most cases these functions return either partially or completely. Sometimes they return spontaneously, more often after neurorehabilitation.
“In both instances recovery is based on neuroplasticity, the ability of the brain to reorganize, that is to change the properties of neurons and to alter the connections between them”, says Dr. Monika Liguz-Lęcznar (Nencki Institute).
After a stroke, neuroplasticity is impaired. Scientists from the Nencki Institute suppose that this may be due to inflammation developing at the site of the stroke. The proof that decreasing inflammation helps neurorehabilitation came from experiments done on rats with experimentally induced stroke. The stroke was localized in a special region of the brain cortex, receiving information from whiskers.
The whiskers are important sensory organs of rodents, allowing the animals to orient themselves in their environment in darkness. Every whisker activates a small, precisely delineated chunk of brain cortex.
In healthy rats neuroplastic changes can be induced by cutting off some of the whiskers, that is by eliminating part of the sensory input to the brain. The brain reacts to that by letting the remaining whiskers take over more cortical space, expand their cortical representation, at the expense of the cut off ones.
“This plastic change does not occur when the site of stroke-induced damage is near the region of cortex ‘belonging’ to the whiskers. We showed that application of ibuprofen decreases inflammation and restores neuroplasticity – the brain cortex reorganizes like in healthy animals”, says Prof. Kossut.
(Source: press.nencki.gov.pl)
A University of Arizona professor is overseeing the manufacture of an experimental drug that could help reduce brain damage after a stroke.
The drug, known as 3K3A-APC, currently is undergoing clinical trials in Europe to determine its safety in humans after proving effective in animal models at reducing brain damage and improving motor skills after a stroke when given in combination with another commonly used stroke therapy.
Thomas Davis, professor of pharmacology in the UA College of Medicine, was chosen to direct the manufacture of the drug for human trials after co-authoring a recent paper in the journal Stroke that pointed to the drug’s effectiveness in rats and mice when used in conjunction with a clot-busting therapy known as tissue plasminogen activator, or tPA.
While tPA is commonly given to sufferers of ischemic stroke, which results from an obstruction in a blood vessel supplying blood to the brain, the therapy poses significant challenges when administered alone, including a limited treatment window, Davis said.
"It has to be given within the first three to four and a half hours of the stroke," Davis said. "It only works in 10 percent of the patients, and it causes bleeding, so tPA alone isn’t that effective."
The most common form of strokes are caused by a sudden reduction in blood flow to the brain (ischemia) that leads to an inadequate supply of oxygen and nutrients. These so-called ischemic strokes are one of the leading causes of death and disability in industrialized nations. If they are not immediately remedied by medical intervention, areas of the brain may die off. In the journal Angewandte Chemie, Korean researchers have now proposed a new approach for supplemental treatment: Ceria nanoparticles could trap the reactive oxygen compounds that result from ischemia and cause cells to die.
It was a quiet Thursday afternoon when AS, a 68-year-old woman from a suburb of Chicago, awakened from a nap to the realization that something was terribly wrong.
When AS woke from her nap, she couldn’t find where doors or cabinets were. She couldn’t name or distinguish familiar household objects. She couldn’t read a book or the numbers on her telephone. She couldn’t see where the bedroom wall ended and the door began. Yet when she saw an ophthalmologist, her vision with glasses was 20/20. She and her husband left the ophthalmologist’s office with a referral to see a neurologist, and “wondering what sort of ailment could rob her of her ability to see the bathroom sink, while leaving her with what we typically think of as perfect vision.”
Balint’s syndrome is named after Austro-Hungarian neurologist Rezső Bálint, who first described it. The condition is caused by one or more strokes in certain regions of the brain. It causes three deficits: Difficulty initiating voluntary eye movements (such as following a physician’s finger); inaccurate arm pointing (a patient can see an object, but is unable to pick it up); and constriction of the visual field (ask a patient to look at a parking lot, and all she sees is a lamp post or a car.)
A Loyola University Medical Center paper “is an attempt to inform both our clinical and subjective understandings of Balint’s syndrome through narratives of two patients suffering from this rare and unique neurological disorder.”
Adding to the mounting evidence that consuming moderate amounts of chocoloate may benefit the heart, comes that of a new study of Swedish men that suggests it may also lower the risk of stroke.