History of technology
I feel for the 30-year-old woman who, in 1962, regularly shuffled around Summersdale Hospital, in England, with a battery pinned to her dress and two silver electrodes, wrapped in gauze, winking above her brow like a second set of eyes. She’d spent half her life in mental asylums: when she was a girl, her father had shot himself, and afterward she’d become convinced that other people could see a mark upon her. Nothing had lifted her malaise, not even shock treatment. When she arrived at Summersdale Hospital, she muttered “Get rid of me” in response to questions. According to the scientific papers that reported on the study, researchers J.W.T Redfearn and O.C.J. Lippold kept her brow area bathed in electricity for as many as 11 hours a day, three treatments a week. The patient began to sleep soundly, no longer tormented by nightmares; she ate well; she prettied herself up; she found a boyfriend. She became, the researchers said, a “different person.”
That year, she was just one of several dozen people wandering the halls of Summersdale with electrodes plastered to their foreheads and batteries on their lapels like boutonnieres. In an earlier study, Lippold and Redfearn had found that they could change the personalities of their subjects with electrical stimulation: positively charged electrodes on the forehead caused people to giggle and chat. Under the influence of negatively charged electrodes, people shut down, became silent and apathetic. Some of the patients had so enjoyed the positive electrodes that they asked for the “battery treatment” again. And so Lippold and Redfearn launched a new study; this time they would expose people — many of them severely depressed — to long sessions of electrical stimulation. The patients were allowed to go home with electrodes glued to their heads, the battery still buzzing. Almost half of them experienced miraculous recoveries. A shell-shocked World War II veteran compared the effects to a shot of whiskey — “I feel quite all right,” he crowed, after he’d been stimulated.
In the decade that followed, other researchers tried to replicate these effects. They produced inconsistent results. Nowadays it’s clear why: researchers applied currents that were too small and glued electrodes to the wrong parts of the scalp. “They used some parameters of stimulation that we know now are not effective. They didn’t have the information that we have now,” according to Fregni. Because the battery-powered electrodes seemed to be unreliable, the medical community lost interest in brain polarization.
Then, in the 1980s, researchers found a much more powerful way to stimulate isolated buttons of the brain. Called repetitive transcranial magnetic stimulation (rTMS), the technique uses electromagnetic radiation — which can easily pass through the skull — to create localized electrical fields near the surface of the brain. The effects of rTMS are dramatic and reproducible. Place the machine’s wand on one part of the scalp and the patient will lose her ability to talk; move the wand to another spot and her leg will jerk.
MORE POWER TO YOU: Researchers wire the author for a round of tDCS.
In essence, rTMS is a souped-up version of the old battery-and-electrodes treatment. But it also comes with greater risks: it can trigger seizures, an arm that won’t stop shaking, or a patient who slumps over in his chair. However, such side effects are rare, and rTMS has proven to be a powerful tool for mapping the brain and modulating brain activity; in the 1990s, researchers began using it (along with other new technologies) to draw blueprints of neural function. This new knowledge, in turn, meant that the battery treatment became relevant again — because now scientists could design a more effective tDCS machine.