(Image caption: Vertebral artery as it passes through the neck vertebrae of the spine and enters the skull base. Arrows indicate head movement during lateral rotation and lateral flexion, motions that may be performed as part of a neck manipulation. Credit: American Heart Association)

Neck manipulation may be associated with stroke

Treatments involving neck manipulation may be associated with stroke, though it cannot be said with certainty that neck manipulation causes strokes, according to a new scientific statement published in the American Heart Association’s journal Stroke.

Cervical artery dissection (CD) is a small tear in the layers of artery walls in the neck. It can result in ischemic stroke if a blood clot forms after a trivial or major trauma in the neck and later causes blockage of a blood vessel in the brain. Cervical artery dissection is an important cause of stroke in young and middle-aged adults.

“Most dissections involve some trauma, stretch or mechanical stress,” said José Biller, M.D., lead statement author and professor and chair of neurology at the Loyola University Chicago Stritch School of Medicine. “Sudden movements that can hyperextend or rotate the neck — such as whiplash, certain sports movements, or even violent coughing or vomiting — can result in CD, even if they are deemed inconsequential by the patient.”

Although techniques for cervical manipulative therapy vary, some maneuvers used as therapy by health practitioners also extend and rotate the neck and sometimes involve a forceful thrust.

There are four arteries that supply blood to the brain: the two carotid arteries on each side of the neck, and the two vertebral arteries on the back of the neck. The influence of neck manipulation seems more important in vertebral artery dissection than in internal carotid artery dissection.

“Although a cause-and-effect relationship between these therapies and CD has not been established and the risk is probably low, CD can result in serious neurological injury,” Biller said. “Patients should be informed of this association before undergoing neck manipulation.”

The association between cervical artery dissection and cervical manipulative therapies was identified in case control studies, which aren’t designed to prove cause and effect. An association means that there appears to be a relationship between two things, i.e., manipulative therapy of the neck and a greater incidence of cervical dissection/stroke. However, it’s not clear whether other factors could account for the apparent relationship.

The relationship between neck manipulation and cervical artery dissection is difficult to evaluate because patients who already are beginning to have a cervical artery dissection may seek treatment to relieve neck pain, a common symptom of cervical artery dissection that can precede symptoms of stroke by several days.

You should seek emergency medical evaluation if you develop neurological symptoms after neck manipulation or trauma, such as:

• Pain in the back of your neck or in your head;
• Dizziness/vertigo;
• Double vision;
• Unsteadiness when walking;
• Slurred speech;
• Nausea and vomiting;
• Jerky eye movements.

“Tell the physician if you have recently had a neck trauma or neck manipulation,” Biller said. “Some symptoms, such as dizziness or vertigo, are very common and can be due to minor conditions rather than stroke, but giving the information about recent neck manipulation can raise a red flag that you may have a CD rather than a less serious problem, particularly in the presence of neck pain.”

Strokefinder quickly differentiates bleeding strokes from clot-induced strokes

The results from the initial clinical studies involving the microwave helmet Strokefinder confirm the usefulness of microwaves for rapid and accurate diagnosis of stroke patients. This is shown in a scientific article published on Monday. Strokefinder enables earlier diagnosis than current methods, which improves the possibility to counteract brain damage.

In the article, researchers from Chalmers University of Technology, Sahlgrenska Academy and Sahlgrenska University Hospital present results from the initial patient studies completed last year. The study included 45 patients, and the results show that the technique can with great certainty differentiate bleeding strokes from clot-induced strokes in patients with acute symptoms.

Strokefinder is placed on the patient’s head where it examines the brain tissue by using microwaves. The signals are interpreted by the system to determine if the stroke is caused by a blood clot or bleeding.

“The results of this study show that we will be able to increase the number of stroke patients who receive optimal treatment when the instrument makes a diagnosis already in the ambulance,” says Mikael Persson, professor of biomedical engineering at Chalmers University of Technology. “The possibility to rule out bleeding already in the ambulance is a major achievement that will be of great benefit in acute stroke care. Equally exciting is the potential application in trauma care.

Diagnosis and treatment already in the ambulance

The initial patient studies have been performed inside hospitals, and this autumn the research groups at Chalmers and Sahlgrenska Academy will test a mobile stroke helmet on patients in ambulances.

“Our goal with Strokefinder is to diagnose and initiate treatment of stroke patients already in the ambulance,” says Mikael Elam, professor of clinical neurophysiology at Sahlgrenska University Hospital. “Since time is a critical factor for stroke treatment, the use of the instrument leads to patients suffering less extensive injury. This in turn can shorten the length of stay at hospitals and reduce the need for rehabilitation, thus providing a number of other positive consequences for both the patient and the health care system.”

Studies involving Strokefinder are currently being conducted at Sahlgrenska University Hospital and Södra Älvsborg Hospital in Borås. The research is being conducted in close collaboration between Chalmers University of Technology, Sahlgrenska Academy, Sahlgrenska University Hospital, Södra Älvsborg Hospital and MedTech West, which is a platform for collaboration in medical device R&D, with premises at Sahlgrenska University Hospital.

A new product, based on the results of the present study, has been developed, and further studies will be conducted in several countries in preparation for the CE approval that Medfield Diagnostics, a spin-off from Chalmers, expects to obtain later this year.

(Illustration: Boid)

How Strokefinder differentiates bleeding strokes from clot-induced strokes

The antennas of the helmet sequentially transmit weak microwave signals into the brain. At the same time, the receiving antennas listen for reflected signals. The brain’s different structures and substances affect the microwave scattering and reflections in different ways. The received signals give a complex pattern, which is interpreted with the help of advanced algorithms. Based on these data, the system can diagnose bleeding or a clot. Bleeding is particularly pronounced, but an area with a clot and oxygen deficiency can also be distinguished. (Watch the video).

With the right rehabilitation, paralyzed rats learn to grip again

After a large stroke, motor skills barely improve, even with rehabilitation. An experiment conducted on rats demonstrates that a course of therapy combining the stimulation of nerve fiber growth with drugs and motor training can be successful. The key, however, is the correct sequence: Paralyzed animals only make an almost complete recovery if the training is delayed until after the growth promoting drugs have been administered, as researchers from the University of Zurich, ETH Zurich and the University of Heidelberg reveal.

Only if the timing, dosage and kind of rehabilitation are right can motor functions make an almost full recovery after a large stroke. Rats that were paralyzed down one side by a stroke almost managed to regain their motor functions fully if they were given the ideal combination of rehabilitative training and substances that boosted the growth of nerve fibers. Anatomical studies confirmed the importance of the right rehabilitation schedule: Depending on the therapeutic design, different patterns of new nerve fibers that sprouted into the cervical spinal cord from the healthy part of the brain and thus aid functional recovery to varying degrees were apparent. The study conducted by an interdisciplinary team headed by Professor Martin Schwab from the Brain Research Institute at the University of Zurich and ETH Zurich’s Neuroscience Center is another milestone in research on the repair of brain and spinal cord injuries.

“This new rehabilitative approach at least triggered an astonishing recovery of the motor skills in rats, which may become important for the treatment of stroke patients in the future,” says first author Anna-Sophia Wahl. At present, patients have to deal with often severe motor-function, language and vision problems, and their quality of life is often heavily affected.

Allow nerves to grow first, then train

On the one hand, the treatment of rats after a stroke involves specific immune therapy, where so-called Nogo proteins are blocked with antibodies. These proteins in the tissue around the nerve fibers inhibit nerve-fiber growth. If they are blocked, nerve fibers begin to sprout in the injured sections of the brain and spinal cord and relay nerve impulses again. On the other hand, the stroke animals, whose front legs were paralyzed, underwent physical training – namely, gripping food pellets. All the rats received antibody treatment first to boost nerve-fiber growth and – either at the same time or only afterwards – motor training. The results are surprising: The animals that began their training later regained a remarkable 85 percent of their original motor skills. For the rats that were trained straight after the stroke in parallel with the growth-enhancing antibodies, however, it was a different story: At 15 percent, their physical performance in the grip test remained very low.

On the one hand, the treatment of rats after a stroke involves specific immune therapy, where so-called Nogo proteins are blocked with antibodies. These proteins in the tissue around the nerve fibers inhibit nerve-fiber growth. If they are blocked, nerve fibers begin to sprout in the injured sections of the brain and spinal cord and relay nerve impulses again. On the other hand, the stroke animals, whose front legs were paralyzed, underwent physical training – namely, gripping food pellets. All the rats received antibody treatment first to boost nerve-fiber growth and – either at the same time or only afterwards – motor training. The results are surprising: The animals that began their training later regained a remarkable 85 percent of their original motor skills. For the rats that were trained straight after the stroke in parallel with the growth-enhancing antibodies, however, it was a different story: At 15 percent, their physical performance in the grip test remained very low.

Meticulous design very promising

The researchers consider timing a crucial factor for the success of the rehabilitation: An early application of growth stimulators – such as antibodies against the protein Nogo-A – triggers an increased sprouting and growth of nerve fibers. The subsequent training is essential to sift out and stabilize the key neural circuits for the recovery of the motor functions. For instance, an automatic, computer-based analysis of the anatomical data from the imaging revealed that new fibers in the spinal cord sprouted in another pattern depending on the course of treatment. By reversibly deactivating the new nerve fibers that grow, the neurobiologists were ultimately able to demonstrate for the first time that a group of these fibers is essential for the recovery of the motor function observed: Nerve fibers that grew into the spinal cord from the intact front half of the brain – changing sides – can reconnect the spinal cord circuits of the rats’ paralyzed limbs to the brain, enabling the animals to grip again.    

“Our study reveals how important a meticulous therapeutic design is for the most successful rehabilitation possible,” sums up study head Martin Schwab. “The brain has enormous potential for the reorganization and reestablishment of its functions. With the right therapies at the right time, this can be increased in a targeted fashion.

Literature:

Wahl, A.S., Omlor, W., Rubio, J.C., Chen, J.L., Zheng, H., Schröter, A., Gullo, M., Weinmann, O., Kobayashi, K., Helmchen, F., Ommer, B., Schwab, M.E. Asynchronous therapy restores motor control by rewiring of the rat corticospinal tract after stroke. Science, June 13, 2014.

Older migraine sufferers may have more silent brain injury

Older migraine sufferers may be more likely to have silent brain injury, according to research published in the American Heart Association’s journal Stroke.

In a new study, people with a history of migraine headaches had double the odds of ischemic silent brain infarction compared to people who said they didn’t have migraines. Silent brain infarction is a brain injury likely caused by a blood clot interrupting blood flow to brain tissue. Sometimes called “silent strokes,” these injuries are symptomless and are a risk factor for future strokes.

Previous studies indicated migraine could be an important stroke risk factor for younger people.

“I do not believe migraine sufferers should worry, as the risk of ischemic stroke in people with migraine is considered small,” said Teshamae Monteith, M.D., lead author of the study and assistant professor of clinical neurology and chief of the Headache Division at the University of Miami Miller School of Medicine. “However, those with migraine and vascular risk factors may want to pay even greater attention to lifestyle changes that can reduce stroke risk, such as exercising and eating a low-fat diet with plenty of fruits and vegetables.”

High blood pressure, another important stroke risk factor, was more common in those with migraine. But the association between migraine and silent brain infarction was also found in participants with normal blood pressure.

Because Hispanics and African-Americans are at increased stroke risk, researchers from the Northern Manhattan Study (NOMAS) – a collaborative investigation between the University of Miami and Columbia University – studied a multi-ethnic group of older adults (41 percent men, average age 71) in New York City. About 65 percent of participants were Hispanic. Comparing magnetic resonance imaging results between 104 people with a history of migraine and 442 without, they found:

• A doubling of silent brain infarctions in those with migraine even after adjusting for other stroke risk factors;
• No increase in the volume of white-matter hyperintensities (small blood vessel abnormalities) that have been associated with migraine in other studies;
• Migraines with aura — changes in vision or other senses preceding the headache — wasn’t common in participants and wasn’t necessary for the association with silent cerebral infarctions.

“While the lesions appeared to be ischemic, based on their radiographic description, further research is needed to confirm our findings,” Monteith said.

The research raises the question of whether preventive treatment to reduce the severity and number of migraines could reduce the risk of stroke or silent cerebral infarction.

“We still don’t know if treatment for migraines will have an impact on stroke risk reduction, but it may be a good idea to seek treatment from a migraine specialist if your headaches are out of control,” Monteith said.

Stem cells from teeth can make brain-like cells

University of Adelaide researchers have discovered that stem cells taken from teeth can grow to resemble brain cells, suggesting they could one day be used in the brain as a therapy for stroke.

In the University’s Centre for Stem Cell Research, laboratory studies have shown that stem cells from teeth can develop and form complex networks of brain-like cells. Although these cells haven’t developed into fully fledged neurons, researchers believe it’s just a matter of time and the right conditions for it to happen.

"Stem cells from teeth have great potential to grow into new brain or nerve cells, and this could potentially assist with treatments of brain disorders, such as stroke," says Dr Kylie Ellis, Commercial Development Manager with the University’s commercial arm, Adelaide Research & Innovation (ARI).

Dr Ellis conducted this research as part of her Physiology PhD studies at the University, before making the step into commercialisation. The results of her work have been published in the journal Stem Cell Research & Therapy.

"The reality is, treatment options available to the thousands of stroke patients every year are limited," Dr Ellis says. "The primary drug treatment available must be administered within hours of a stroke and many people don’t have access within that timeframe, because they often can’t seek help for some time after the attack.

"Ultimately, we want to be able to use a patient’s own stem cells for tailor-made brain therapy that doesn’t have the host rejection issues commonly associated with cell-based therapies. Another advantage is that dental pulp stem cell therapy may provide a treatment option available months or even years after the stroke has occurred," she says.

Dr Ellis and her colleagues, Professors Simon Koblar, David O’Carroll and Stan Gronthos, have been working on a laboratory-based model for actual treatment in humans. As part of this research Dr Ellis found that stem cells derived from teeth developed into cells that closely resembled neurons.

"We can do this by providing an environment for the cells that is as close to a normal brain environment as possible, so that instead of becoming cells for teeth they become brain cells," Dr Ellis says.

"What we developed wasn’t identical to normal neurons, but the new cells shared very similar properties to neurons. They also formed complex networks and communicated through simple electrical activity, like you might see between cells in the developing brain."

This work with dental pulp stem cells opens up the potential for modelling many more common brain disorders in the laboratory, which could help in developing new treatments and techniques for patients.

Airport security-style technology could help doctors decide on stroke treatment

A new computer program could help doctors predict which patients might suffer potentially fatal side-effects from a key stroke treatment.

The program, which assesses brain scans using pattern recognition software similar to that used in airport security and passport control, has been developed by researchers at Imperial College London. Results of a pilot study funded by the Wellcome Trust, which used the software are published in the journal Neuroimage Clinical.

Stroke affects over 15 million people each year worldwide. Ischemic strokes are the most common and these occur when small clots interrupt the blood supply to the brain. The most effective treatment is called intravenous thrombolysis, which injects a chemical into the blood vessels to break up or ‘bust’ the clots, allowing blood to flow again.

However, because intravenous thombolysis effectively thins the blood, it can cause harmful side effects in about six per cent of patients, who suffer bleeding within the skull. This often worsens the disability and can cause death.

Clinicians attempt to identify patients most at risk of bleeding on the basis of several signs assessed from brain scans. However, these signs can often be very subtle and human judgements about their presence and severity tend to lack accuracy and reliability.

In the new study, researchers trained a computer program to recognise patterns in the brain scans that represent signs such as brain-thinning or diffuse small-vessel narrowing, in order to predict the likelihood of bleeding. They then pitted the automated pattern recognition software against radiologists’ ratings of the scans. The computer program predicted the occurrence of bleeding with 74 per cent accuracy compared to 63 per cent for the standard prognostic approach.

Dr Paul Bentley from the Department of Medicine, lead author of the study, said: “For each patient that doctors see, they have to weigh up whether the benefits of a treatment will outweigh the risks of side effects. Intravenous thrombolysis carries the risk of very severe side effects for a small proportion of patients, so having the best possible information on which to base our decisions is vital. Our new study is a pilot but it suggests that ultimately doctors might be able to use our pattern recognition software, alongside existing methods, in order to make more accurate assessments about who is most at risk and treat them accordingly. We are now planning to carry out a much larger study to more fully assess its potential.”

The research team conducted a retrospective analysis of computerized tomography (CT) scans from 116 patients. These are scans that use x-rays to produce ‘virtual slices’ of the brain. All the patients had suffered ischemic strokes and undergone intravenous thrombolysis in Charing Cross Hospital. In the sample the researchers included scans from 16 patients who had subsequently developed serious bleeding within the brain.

Without knowing the outcomes of the treatment, three independent experts examined the scans and used standard prognostic tools to predict whether patients would develop bleeding after treatment.

In parallel the computer program directly assessed and classified the patterns of the brain scans to produce its own predictions.

Researchers evaluated the performance of both approaches by comparing their predictions of bleeding with the actual experiences of the patients.

Using a statistical test the research showed the computer program predicted the occurrence of bleeding with 74 per cent accuracy compared to 63 per cent for the standard prognostic approach. 

The researchers also gave the computer a series of ‘identity parades’ by asking the software to choose which patient out of ten scans went on to suffer bleeding. The computer correctly identified the patient 56 per cent of the time while the standard approach was correct 31 per cent of the time.

The researchers are keen to explore whether their software could also be used to identify stroke patients who might be helped by intravenous thrombolysis who are not currently offered this treatment. At present only about 20 per cent of patients with strokes are treated using intravenous thrombolysis, as doctors usually exclude those with particularly severe strokes or patients who have suffered the stroke more than four and half hours before arriving at hospital. The researchers believe that their software has the potential to help doctors to identify which of those patients are at low risk of suffering side effects and hence might benefit from treatment.

Beating the clock for sufferers of ischemic stroke

A ground-breaking computer technology raises hope for people struck by ischemic stroke (缺乏血性中風), which is a very common kind of stroke accounting for over 80 per cent of overall stroke cases. Developed by research experts at The Hong Kong Polytechnic University (PolyU), this novel application that expertly analyses brain scans could save lives by helping doctors determine if a patient has the life-threatening condition.

The CAD stroke technology is capable of detecting signs of stroke from computed tomography (CT) scans. A CT scan uses X-rays to take pictures of the brain in slices. When blood flow to the brain is blocked, an area of the brain turns softer or decreases in density due to insufficient blood flow, pointing to an ischemic stroke.

As demonstrated by Dr Fuk-hay Tang from the Department of Health Technology and Informatics at PolyU, CT scans are fed into the CAD stroke computer, which will make sophisticated calculations and comparisons to locate areas suspected of insufficient blood flow. In 10 minutes, scans with highlighted areas of abnormality will come out for doctors’ review. Early changes including loss of insular ribbon, loss of sulcus and dense MCA signs can be identified, helping doctors determine if blood clots are present.

Ischemic stroke occurs when an artery to the brain is blocked, cutting off oxygen and essential nutrients being sent to the brain, and brain cells will die in just a few minutes. Clot-busting drugs are effective in minimising brain damage but they should be administered within 3 hours from the onset. Immediate diagnosis and treatment are therefore absolutely essential.

In that sense, a diagnostic tool that can expedite the process will be greatly helpful in saving lives. As Dr Tang shared with us, “The clock is ticking for stroke patients. Medications taken in three hours from the onset of stroke are deemed most effective. Chances of recovery decrease with every minute passing by. It usually takes half an hour for the ambulance to arrive at the hospital, at best. Then, another 45 minutes to 1 hour are needed for CT or MRI scans after the patient has been checked and dispatched for the test, which means some waiting and time will slip by. Afterwards, the brain scan will take another 10 to 15 minutes. If our tool can help doctors arrive at a diagnosis in 10 minutes, the shorter response time will make meeting the target more achievable.”

“It might come in handy for physicians with less experience in stroke,” added Dr Tang, “and patient care can be maintained in hospitals where human and other vital resources are already stretched to the limit.”

The life-saving application can also detect subtle and minute changes in the brain that would escape the eye of even an experienced specialist, slashing the chances of missed diagnosis. False-positive and false-negative cases, and other less serious conditions that mimic a stroke can also be ruled out, allowing a fully-informed decision to be made.

Furthermore, equipped with the built-in artificial intelligence feature, the CAD stroke technology would learn by experience. With every scan passing through, along with feedback from stroke specialists, the application will improve on its accuracy over time.

“It is important to identify stroke patients and help them get the urgent treatment they need,” said Dr Tang. “Prompt and accurate diagnosis is in the forefront of our minds when designing the medical application. Healthcare professionals should focus on what they do best and let us take care of the rest.”

Study IDs new cause of brain bleeding immediately after stroke

By discovering a new mechanism that allows blood to enter the brain immediately after a stroke, researchers at UC Irvine and the Salk Institute have opened the door to new therapies that may limit or prevent stroke-induced brain damage.

A complex and devastating neurological condition, stroke is the fourth-leading cause of death and primary reason for disability in the U.S. The blood-brain barrier is severely damaged in a stroke and lets blood-borne material into the brain, causing the permanent deficits in movement and cognition seen in stroke patients.

Dritan Agalliu, assistant professor of developmental & cell biology at UC Irvine, and Axel Nimmerjahn of the Salk Institute for Biological Studies developed a novel transgenic mouse strain in which they use a fluorescent tag to see the tight, barrier-forming junctions between the cells that make up blood vessels in the central nervous system. This allows them to perceive dynamic changes in the barrier during and after strokes in living animals.

While observing that barrier function is rapidly impaired after a stroke (within six hours), they unexpectedly found that this early barrier failure is not due to the breakdown of tight junctions between blood vessel cells, as had previously been suspected. In fact, junction deterioration did not occur until two days after the event.

Instead, the scientists reported dramatic increases in carrier proteins called serum albumin flowing directly into brain tissue. These proteins travel through the cells composing blood vessels – endothelial cells – via a specialized transport system that normally operates only in non-brain vessels or immature vessels within the central nervous system. The researchers’ work indicates that this transport system underlies the initial failure of the barrier, permitting entry of blood material into the brain immediately after a stroke (within six hours).

“These findings suggest new therapeutic directions aimed at regulating flow through endothelial cells in the barrier after a stroke occurs,” Agalliu said, “and any such therapies have the potential to reduce or prevent stroke-induced damage in the brain.”

His team is currently using genetic techniques to block degradation of the tight junctions between endothelial cells in mice and examining the effect on stroke progression. Early post-stroke control of this specialized transport system identified by the Agalliu and Nimmerjahn labs may spur the discovery of imaging methods or biomarkers in humans to detect strokes as early as possible and thereby minimize damage.

New therapy helps to improve stereoscopic vision in stroke patients

Humans view the world through two eyes, but it is our brain that combines the images from each eye to form a single composite picture. If this function becomes damaged, impaired sight can be the result. Such loss of visual function can be observed in patients who have suffered a stroke or traumatic brain injury or when the oxygen supply to the brain has been reduced (cerebral hypoxia). Those affected by this condition experience blurred vision or can start to see double after only a short period of visual effort. Other symptoms can include increased fatigue or headaches. It is been suggested that these symptoms arise because the brain is unable to maintain its ability to fuse the separate images from each eye into a single composite image over a longer period. Experts refer to this phenomenon as binocular fusion dysfunction.

‘As a result, these patients have significantly reduced visual endurance,’ explains Katharina Schaadt, a graduate psychology student at Saarland University. ‘This often severely limits a patient’s ability to work or go about their daily life.’ Working at a computer screen or reading the newspaper can be very challenging. As binocular fusion is a fundamental requirement for achieving a three-dimensional impression of depth, those affected also frequently suffer from partial or complete stereo blindness. ‘Patients suffering from stereo blindness are no longer able to perceive spatial depth correctly,’ says Schaadt. ‘In extreme cases, the world appears as flat as a two-dimensional picture. Such patients may well have difficulties in reaching for an object, climbing stairs or walking on uneven ground.’

Although about 20% of stroke patients and up to 50% of patients with brain trauma injuries suffer from these types of functional impairments, there is still no effective therapy. Researchers at Saarland University working with Anna Katharina Schaadt and departmental head Professor Georg Kerkhoff have now developed a novel therapeutic approach and have examined its efficacy in two studies. ‘Test subjects underwent a six week training program in which both eyes were exercised equally,’ explains Schaadt. The aim was to train binocular fusion and thus improve three-dimensional vision. Participants in the study were presented with two images with a slight lateral offset between them. By using what are known as convergent eye movements, patients try to fuse the two images to a single image. This involves directing the eyes inward towards the nose while always keeping the images in the field of view. With time, the two images fuse to form a single image that exhibits stereoscopic depth, i.e. the patient has re-established binocular single vision.

The team of clinical neuropsychologists at Saarland University have used this training programme on eleven stroke patients, nine patients with brain trauma injury and four hypoxia patients. After completing the training programme, a significant improvement in binocular fusion and stereoscopic vision was observed in all participants. In many cases, a normal level of stereovision was attained. ‘The results remained stable in the two post-study examinations that we performed after three and six months respectively,’ says Schaadt. ‘Visual endurance also improved significantly.’ Patients who were able to work at a computer for only 15 to 20 minutes before they began treatment found that they could work at a computer screen for up to three hours after completing the therapeutic training programme.

The results are also of theoretical value to the Saarbrücken scientists, as they provide insight into brain function and indicate that certain regions of the brain that have been become damaged can be reactivated if the appropriate therapy is used.