Edward Fruitman, MD
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post stroke

TMS Could Help Treat Chronic Dizziness

Researchers from the Johns Hopkins University School of Medicine believe that they have located a specific site in the human brain that could be one of the sources of dizziness and spatial disorientation.

While dizziness can also be linked to damage to the inner ear, or to other senses such as vision, neurology instructor Dr. Amir Kheradmand and his colleagues report that they have discovered a region of the brain that plays a vital role in our subconscious awareness of which way is up and which way is down.

Their study, which appears online in the journal Cerebral Cortex, found that some causes of dizziness, unsteadiness and “floating” could be linked to that region in the parietal cortex.

The study authors opted to focus their analysis on the right parietal cortex, as research on stroke victims with balance problems has suggested that damage to that region of the brain was directly involved with upright perception.

They recruited eight healthy subjects, placing each in a dark room and showing them lines that were illuminated on a screen. Dr. Kheradmand’s team then had the study participants report the orientation of each line by rotating a dial to the left, the right, or straight ahead.

The subjects then received (TMS) – an FDA-approved treatment for depression and which “painlessly and noninvasively delivers electromagnetic currents to precise locations in the brain.”

Each individual had a TMS coil placed behind the ear and against the scalp across the right parietal lobe. The subjects received 600 electromagnetic pulses over the course of 40 seconds, and at the end of each session, they were asked a second time to show the researchers which way the illuminated line was positioned. At the end of the study, all of the subjects reported that his or her sense of being upright had been altered in the same way after TMS was administered in the same location in the parietal cortex.

According to Kheradmand, his team’s findings suggest that this form of stimulation could be used to treat chronic dizziness. “If we can disrupt upright perception in healthy people using TMS, it might also be possible to use TMS to fix dysfunction in the same location in people with dizziness and spatial disorientation,” he said.

INHIBITORY RIGHT-BRAIN TMS IMPROVES LANGUAGE AFTER STROKE

Sue Hughes-Medscape(July 11, 2013)

Use of inhibitory transcranial magnetic stimulation (TMS) over the speech area in the right side of the brain significantly improved language recovery in patients with stroke, new research shows.

“The dominant language center is normally in the left hemisphere of the brain. After a stroke, when this area is damaged, similar regions in the right hemisphere take over, but this is not as effective as if the left side recovers. Brain imaging studies show that stroke patients with right hemisphere activation generally do worse. So we used TMS treatment to inhibit the right hemisphere area, so the left hemisphere area has to function,” lead investigator Alexander Thiel, MD, McGill University, Montreal, Quebec, Canada, told Medscape Medical News.

First Proof-of-Concept Study

Dr. Thiel compared the strategy with treating someone who has paralysis on 1 side of their body.

“If someone has paralysis of one arm, if you immobilize the good arm, the patient is forced to use the paralyzed arm, which helps it recover.”

The inhibitory TMS is carried out by positioning a hand-held electromagnetic coil over the appropriate part of the brain. The fluctuating magnetic field induces an electrical current that blocks normal function.

Dr. Thiel noted that a few single case reports and case series of this treatment have been published previously, but this is the first randomized proof-of-concept study.

The study involved 24 patients (all right-handed) with subacute post-stroke aphasia from the rehabilitation hospital RehaNova in Cologne, Germany. They were randomly assigned to a 10-day protocol of 20-minute inhibitory 1-Hz TMS over the right triangular part of the posterior inferior frontal gyrus or sham stimulation, followed by 45 minutes of speech and language therapy.

Activity in language networks was measured with O-15-water positron emission tomography before and after treatment, and language performance was assessed by using the Aachen Aphasia Test (AAT) battery.

Results showed that language performance was significantly improved in the TMS group. The largest improvements were seen in the subtest of naming objects, but comprehension, token test, and writing also all improved.

Imaging results showed that patients in the TMS group also activated proportionally more voxels in the left hemisphere language center after treatment than before (difference in activation volume index) compared with sham-treated patients. There was a moderate but significant linear relationship between activation volume index change and global AAT score change.

“We found that patients who underwent the real TMS treatment had 2-3 times better recovery of their aphasia than patients who were given the sham treatment. The principal improvement was in the ability to name objects. This is very important — you cannot communicate if you can’t name things,” said Dr. Thiel.

Pronounced Effect

“This study is telling us that this therapy seems to work the way we think it should. We are very excited by these results. We were a little surprised by the magnitude of the effect. We didn’t expect it to be so pronounced. But the fact that the imaging results showed a shift in brain activity from the right to the left, corresponding with the improvement in aphasia, is reassuring and supports that this model is pathophysiologically valid.”

He noted that the effect was measured immediately after the treatment. “How long it will last we don’t know. Some previous studies suggest it does last long-term, but we need to study this further.”

The next step is to try reproducing these results in a larger study. Such a study — NORTHSTAR — is now planned to start in October. Funded by the Canadian Institutes of Health Research, it will involve 100 patients from Canada and Germany. Patients will be assessed at day 10, as in the current study, but also longer term — about a month after treatment stops.

In the current study, patients were treated within 3 months after stroke. In the next study they will be treated within 1 month.

“We think the earlier we perform this treatment the more likely it is to be effective, as we believe there is a window of a few weeks after stroke when the right side of the brain becomes very active.

“We have seen this in imaging studies. Eventually it shifts back to the left. But the more the left brain takes over again the better the recovery. This treatment is just trying to accelerate this naturally occurring pattern,” said Dr. Thiel.

Asked about risks, Dr. Thiel reported that aphasia did not deteriorate with the treatment.

The main adverse effect is headaches because TMS can cause the scalp muscles to contract, but these are benign and respond to normal headache treatments, he said.