Tag: Stroke

Mild electrical stimulation shows promise in reviving stroke-damaged brains:-

Shova Paul, a 55-year-old housewife, was rushed to the emergency unit of a hospital after she was found lying on the floor of the toilet well past midnight. A quick examination and a subsequent brain scan revealed an awake and alert patient unaware of her illness (anosognosia). She had lost senses on the left side of the body (hemiplegia) and the brain image showed tell-tale signs of damage in the movement and language centres (sensorimotor cortex and Broca’s area). While recording the obvious signs of a severe cerebral stroke the doctor could apprehend what was coming: even after the best possible medical care, she wouldn’t be able to move, speak, read, write or comprehend what others were saying.

Now, two years after that incident, Paul leads a hemiplegic’s life. Like countless other hapless stroke survivors, she can’t move on her own, speaks with a slurred accent and has an impaired vision. To regain some control of the damaged muscles and relearn simple chores she undergoes a rehabilitation regime, which includes prolonged physiotherapy and psychological counselling.

Yet the lives of hundreds of thousands of stroke survivors like Paul can be dramatically transformed by a simple, inexpensive technique developed many decades ago, but largely forgotten. According to a new study reported last week, electrical brain stimulation — a procedure that delivers mild electric current to the brain non-invasively — has been shown to help severely affected stroke patients recover their ability to move and speak. In the therapy, known as transcranial direct current stimulation (tDCS), a mild electrical jolt is passed to the brain through the scalp and skull of the patient — perceived as a slight tingle in the head. “The concept of using therapeutic electricity on excitable tissue such as that of the brain is not new, considering the attempts to cure epileptic disorders with electric catfish as early as in the 11th century (by an Arab physician called Ibn-Sidah),” writes Gottfried Schlaug, the principal investigator of the study which appeared in the journal Archives of Neurology. He also points out that in the late 19th century physicians had used mild electrical stimulation to treat patients with depression. According to Schlaug, a neurologist at the Beth Israel Deaconess Medical Center (BIDMC) at Harvard Medical School in Boston, non-invasive brain stimulation using tDCS is “fast re-emerging as an interventional tool to modulate the effects, and possibly treat the symptoms, of several neurological and psychiatric disorders.”

However tDCS should not be confused with its controversial cousin electroconvulsive therapy (ECT), or electro shock, used for the treatment of severe depression. Unlike shock therapy — which is more drastic, giving a giant 600 milliampere (mA) buzz and affecting the entire brain, causing a seizure and memory loss — tDCS is much gentler (2mA) and more selective in the sense that it excites or inhibits brain regions directly underneath the positioned electrode. Moreover, ECT always requires the use of anaesthesia and is more invasive.
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Schlaug and his collaborators at the BIDMC tested tDMC on 20 patients who had suffered a stroke about two-and-a-half years back and still had moderate to severe impairments. Patients performed 60 minutes of routine rehabilitation procedures each day for five days while also receiving a 30-minute session of either active electrical stimulation or a placebo (‘sham’ treatment designed to mimic electrical stimulation). A simple nine volt battery connected to a piece of moistened sponge was used to deliver the mild electrical jolt. Within a week, patients given the real treatment were found to perform better in basic motor tests such as grasping a cup. A brain scan showed that activity in the injured part of the brain increased after the treatment. Schlaug presented the findings of the research at a conference at San Francisco last week.

Although it is not yet clear exactly how tDCS works, Sclaug believes that the electrical stimulation augments recovery in stroke patients by re-establishing communication between the damaged and unaffected halves or hemispheres of the brain. In other words, a stroke creates an imbalance in the normal communication of the brain’s hemispheres such that the unaffected hemisphere becomes functionally dominant and inhibits the damaged hemisphere.

“There is no denying that tDCS has an immense potential for repairing the stroke-damaged brain, but the problem is that it is still in an experimental stage,” says Dr J.N. Roy, a stroke neurologist at the Advanced Medicare Research Institute (AMRI) in Calcutta, who had attended to Paul two years ago. “Unless there is a huge trial involving a large number of patients, and the underlying neurophysiological changes are properly explained, one can’t put it into use in a routine rehab programme,” he adds. In fact, Schlaug’s team is trying to understand better the changes that take place in the brain as patients recover.

Countless neurologists like Roy and patients like Paul around the world are waiting for their results.

Source:Thje Telegraph (Kolkata, India)

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