A new non-invasive device, which delivers short magnetic pulses to the brain, promises to combat depression

BATTLING THE BLUES

 The US government has approved the first non-invasive brain stimulator to treat depression – a device that beams short magnetic pulses through the skull to spark brain cells to fire. Called transcranial magnetic stimulation (TMS), this approach doesn't cause the risks of surgically implanted electrodes or shock therapy, researchers say in the new study.
    "We are opening up a whole new area of medicine," says Dr Mark George of the Medical University of South Carolina, who helped pioneer the use of TMS in depression. "Now, there's a whole field of non-invasive electrical stimulation of the brain that's moving forward."
HOW IT WORKS
Neuroscientists have been using TMS for years as a research tool in brain studies. Zap a powerful magnet over a certain spot on the head – where motion is controlled – and someone's arm can suddenly, involuntarily, lash out. Beyond the "wow" factor, magnetised pulses were triggering brain activity.
    The question was how to harness that activity in a way that might cure disease. TMS is also being studied in stroke rehabilitation and other brain disorders.
    "Nobody thought this would work; it was a crazy idea. I had to do it in the morning before the real scientists came in," George laughs, as he recalls the work he began in 1993.
    "The brain is an electrical organ," he explains. "Electricity is the currency of the brain. It's how the brain does what it does."
    For depression, psychiatrists aim the magnet at the left front of the head – the prefrontal cortex.
    Since everyone's brain is different, they first zap the head to find a patient's motor-control region, and then carefully move 5 cms forward.
    Then, the device beams about 3,000 pulses a minute during a 40-minute treatment, done about five times a week for up to six weeks.
    The theory: Stimulating brain cells in the prefrontal cortex triggers a chain reaction that also stimulates deeper brain regions involved with mood.
    TMS did prove to be very safe: Patients in the study suffered no seizures or memory problems like shock therapy can cause, or other reactions throughout the body. The chief complaint from the sessions was headaches.
BUT HOW GOOD IS IT?
While there is a need for innovative approaches – at least one in five depression patients is treatment-resistant – the question is just how much benefit TMS offers.
    The US' Food and Drug Administration department cleared Neuronetics Inc's NeuroStar device based on data that found patients did modestly better when treated with TMS than when they unknowingly received a sham treatment that mimicked the magnet. It was a study fraught with statistical questions that concerned the agency's own scientific advisors.
    Still, about 24 per cent of those who got TMS scored significantly better on standard depression measures after six weeks, compared with 12 per cent who got the sham, says study leader Dr Philip Janicak.
    However, some reported remarkable improvement, like 60-year-old Steve Newman: "One day it was like a light switch went off."
    Newman had suffered from repeated bouts of depression since he was a teenager, and drug after drug barely blunted it. He was considering shock therapy when he heard about TMS.
    After two weeks of treatment, Newman was wondering if he was getting the sham – when suddenly, he started feeling a lot better, and doctors spotted a corresponding major improvement in his depression measurements.
    "I was awake. I was there," says Newman, who still gets what he calls a "maintenance dose" of TMS about once a month.
    Quantifying the benefit is key. For a clearer answer on the technology's benefits, the US' National Institutes of Health has an independent study under way now that tracks 260 patients undergoing TMS, and may have initial results as early as next year. AP

A doctor from Neuronetics Inc administers the transcranial magnetic stimulation procedure using the company's NeuroStar device, which sends short magnetic pulses to stimulate brain cells that control moods. The device – recently approved by the US government's FDA – can help treat depression, its inventors say