'Roused from coma' by a magnetic field

摘要

Josh villa was 26 and driving home after a drink with a friend on 28 August 2005 when his car mounted the kerb and flipped over. Villa was thrown through the windscreen, suffered massive head injuries and fell into a coma. Almost a year later, there was little sign of improvement. "He would open his eyes, but he was not responsive to any external stimuli in his environment," says Theresa Pape of the US Department of Veterans Affairs in Chicago, who helped treat him. Usually there is little more that can be done for people in this condition. Villa was to be sent home to Rockford, Illinois, where his mother, Laurie McAndrews, had volunteered to care for him. But Pape had a different suggestion. She enrolled him in a six-week study in which an electromagnetic coil was held over the front of his head to stimulate the underlying brain tissue. Such transcranial magnetic stimulation (TMS) has been investigated as a way of treating migraine, stroke, Parkinson's disease and depression, with some promising results, but this is the first time it has been used as a potential therapy for someone in a coma-like state. The rapidly changing magnetic fields that the coil creates can be used either to excite or inhibit brain cells - making it easier or harder for them to communicate with one another. In Villa's case, the coil was used to excite brain cells in the right prefrontal dorsolateral cortex. This area has strong connections to the brainstem, which sends out pulses to the rest of the brain that tell it to pay attention. "It's like an 'OK, I'm awake' pulse," says Pape.