An insulated electric coil carrying a strong, pulsing electric current generates a constantly changing magnetic field that penetrates the skull when a technician holds the device against the patient's head. In turn, the magnetic field produces an electric current inside the brain. Many patients wish to avoid electroconvulsive therapy, which has a frightening reputation left over from the mid-20th century. Then, the procedure often produced se vere, sometimes injurious, seizures. Though shock treatment is now far milder and used frequently, it does require general anesthesia.
Some patients prefer a less aggressive therapy.
The electric current in electroconvulsive therapy stimulates not only the prefrontal cortex but the entire brain, including the memory center and the motor-control area. Effects can include short-term memory loss as well as seizures, though today these are more like a shiver than a major convulsion. Magnetic stimulation, by contrast, focuses tightly on the prefrontal cortex, avoiding the motor-control area and making seizures far less likely, Avery said. The patient, awake and sitting in a chair, feels nothing or possibly a slight tingling on the surface of the skin where the magnetic device touches. There's no short-term memory loss or other known side effects, he said.