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Transcranial Magnetic Stimulation Update

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    NHNE News List Current Members: 760 Subscribe/unsubscribe/archive info at the bottom of this message. ... ZAP! SCIENTIST BOMBARDS BRAINS WITH SUPER-MAGNETS TO
    Message 1 of 1 , Jan 16, 2003
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      NHNE News List
      Current Members: 760
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      By Carey Goldberg
      Boston Globe
      January 14, 2003


      Just by pointing his super-magnets at the right spots on your head, Dr.
      Alvaro Pascual-Leone can make you go momentarily mute or blind.

      He can disrupt your working memory or your ability to recognize faces. He
      can even make it harder for you to say verbs while nouns remain as easy as

      Weird, yes. Fringe, no.

      Pascual-Leone is one of the premier scientific pioneers exploring a new
      technique called transcranial magnetic stimulation, or TMS, which shuts down
      or revs up the electrical doings inside the brain by sending a potent
      magnetic field through the skull.

      This is no try-it-at-home parlor trick and no ''Relieve your Pain!''
      magnetic bracelet or insole.

      Invented in 1985, modern-day magnetic stimulators charge up to a whopping
      3,000 volts and produce peak currents of up to 8,000 amps -- powers similar
      to those of a small nuclear reactor.

      That pulse of current flowing from a capacitor into a hand-held coil creates
      a magnetic field outside the patient's head. The field painlessly induces a
      current inside the brain, affecting the electrical activity that is the
      basis for all it does.

      The promise of TMS as a scientific tool seems similarly powerful. And it has
      generated a range of intriguing practical effects as well, from improving
      attention to combating depression, that have been published in reputable,
      peer-reviewed journals.

      ''From the point of view of cognitive neuroscience -- understanding how
      brain activity relates to behavior -- it is, in a way, a dream come true for
      all of us, because it provides a way to create our own patients, as it
      were,'' said Pascual-Leone, director of the Laboratory for Magnetic Brain
      Stimulation at Beth Israel Deaconess Medical Center. ''You can create a very
      transient disruption of the brain. For a few milliseconds, it is as if those
      cells were not there. So you are able to ask questions about what role a
      particular brain part plays in a particular behavior.''

      More and more, TMS also appears to hold the potential for therapy to help
      with brain problems, including depression, Parkinson's Disease and stroke.

      Evidence, including a seminal paper by Pascual-Leone in 1996, has been
      mounting that repeated sessions of TMS can alleviate recalcitrant cases of
      depression, and without the nasty side effects of electroshock treatment.

      Hundreds of studies in the past decade have explored myriad potential TMS
      targets, including schizophrenia and post-traumatic stress disorder. Most
      recently, a small study published last month found that applying TMS to
      parts of the brain involved in processing sound could temporarily reduce the
      endless buzzing-in-the-ears of tinnitus.

      Pascual-Leone and his colleagues plan to try TMS next month on patients
      whose ability to speak has been damaged by stroke. Preliminary work
      indicates that their brains, in trying to repair the damage, may have
      rewired themselves wrong. So blocking certain areas can actually help the
      patients speak better, he said.

      He has a full shopping list of other projects held up only by lack of money,
      including plans to expand on work using TMS to relieve chronic pain and to
      speed up the learning of physical skills. For all his own obvious
      excitement, Pascual-Leone's talk is constantly punctuated by caveats that
      TMS is too unproven for other people to get too excited.

      For the most part in those hundreds of studies, he said, he hears ''a
      premature ringing of the bells. It may help some people but it risks
      creating a lot of premature expectations that may not hold true in the

      Still, he's not against a few flights of fancy. What if, he asked, TMS could
      block the brain activity associated with lying, and witnesses would get
      zapped before taking the stand? ''It opens up all kinds of cans of worms,''
      he said.

      Or take the question of mental enhancement. Pascual-Leone was the first to
      demonstrate that TMS can not only block brain functioning, it can
      temporarily enhance it as well. In some studies, TMS has appeared to improve
      subjects' working memories, speed up their problem-solving, and sharpen
      their attention.

      Might it be possible, he wondered, to pre-activate a person's brain with TMS
      and enable them to learn faster? What if some day a student could rev up one
      part of his brain before French class and another before a piano lesson?

      TMS is far too crude and little-tried at this point to allow for such
      specific interventions. Still, the military is already aiming for TMS
      enhancement. Researchers at the Brain Stimulation Laboratory at the Medical
      University of South Carolina announced last year that they had received a $2
      million government grant to develop a TMS device -- probably a helmet -- to
      sharpen the minds of sleep-deprived soldiers while they wore it.

      Ultimately, Pascual-Leone said, the field will likely move in the direction
      of developing such longer-term TMS devices. Already, repeated stimulations
      can apparently produce effects lasting for weeks afterward, by revving up
      underactive areas or quieting down overactive spots for long enough that the
      changes linger even after the stimulation stops.

      But these are still very early days. TMS is conveniently noninvasive --
      years ago, it took electrodes inserted in an open brain to produce similar
      results -- and it appears to have virtually no side effects. But there is
      always risk with something so new, Pascual-Leone cautioned, in particular,
      risk that it could cause some unexpected long-term harm.

      Dr. John A. Cadwell of Cadwell Laboratories in Kennewick, Wash., which began
      producing a commercially viable TMS machine back in 1990, agreed: ''I think
      it's a good tool, but it's not one that should be sold at Wal-Mart just

      Inventors had been tinkering with the application of powerful magnets to the
      human brain since the end of the 19th century. But it was only in 1985 that
      Dr. Anthony T. Barker, a professor of medical physics at the University of
      Sheffield in England, finally created the first effective transcranial

      Barker is a skeptic about any other medical claims for garden-variety
      magnets, he said, but he no longer doubts that TMS can affect mood, at the
      very least.

      ''I think it's going to be useful,'' he said. ''Whether it will be very,
      very useful, only time will tell.''

      Many of the initial volunteers for TMS experiments were the researchers
      themselves, on the principle that they should not ask subjects to do what
      they would not do themselves.

      ''I've probably had more zaps to my brain than anybody else on the planet,''
      Barker said blithely.

      The beginning was not so blithe: There were real questions about whether TMS
      might induce some of the complications -- memory loss, seizures -- that
      electroshock can bring.

      Cadwell recalled that in the early days of testing a TMS machine, ''No one
      knew if we were going to be the next one to have a seizure, or if 12 years
      of medical residency would suddenly get blown away.''

      TMS did induce several seizures in participants in the early years, but
      researchers have since worked out technical safety rules that prevent them
      and established that no significant memory loss occurs.

      Pascual-Leone, 41, who did the first TMS safety study and wrote the first
      paper on TMS ethics, has zapped himself countless times, too. The zapping
      looks strange but not scary: When a post-doctoral student, Yukiyasu
      Kamitani, sat for a dress rehearsal of a TMS experiment the other day, it
      sounded like nothing more than a bag of microwave popcorn on its final pops,
      and felt, Kamitani said, like someone was lightly flicking his scalp.

      Still, though TMS is already starting to be offered in Canada (see
      <http://www.mindcarecentres.com>), it appears unlikely that it will arrive
      soon in American clinics.

      Cadwell, the American manufacturer, said that TMS devices are approved for
      clinical use in most other countries, but not by the FDA. So, he said,
      pronouncing the ultimate clinical death knell, ''It's not a billable



      THE NO-DOZE SOLDIER (12/19/2002):








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