WE HAVE ALWAYS BEEN BIONIC
was apparently cured by the procedure, at least for a time. ECT came into heavy use in the 1940s and 1950s, but fell out of favor because of the violent physical convulsions it induced, along with reports of un- desirable mental side effects and the possibility of misuse, as dramati- cally illustrated in the 1975 film One Flew Over the Cuckoo’s Nest.The introduction of alternatives such as psychiatric drug therapy also made the method less desirable. Recently ECT has seen a comeback in treating severe depression, but the method remains controversial.
Electricity can affect the nerves and the brain in subtle and appar- ently benign ways as well as in overt and violent ones. Electrical stimu- lation of the vagus nerve, for example, has reduced the frequency of epileptic effects in many patients, although the reasons for this out- come are not entirely understood.The vagus is a complicated, widely distributed nerve (its name comes from a Latin root meaning “wan- dering”) that runs from the brain stem—which connects the brain to the spinal cord—through the neck and thorax to the abdomen. It has functions related to the ears, tongue, larynx, stomach, and heart. Epi- lepsy is a chronic disorder of the nervous system, in which seizures arise from excessive interaction among the neurons in the brain.While drugs can reduce that abnormal activity, another possible therapy arose from work dating back to the 1930s, which showed that stimulation of the vagus nerve affects brain activity. In the 1980s, researchers pro- posed that controlled electrical stimulation of the vagus nerve could desynchronize the brain’s neural signals and hence potentially blunt epileptic effects.
That led to the technique called VNS, vagus nerve stimulation, which has proven beneficial for epileptics whose condition is inoper- able and does not respond to drugs. In VNS, an electronic pulser the size of a large coin is implanted under the skin on the left side of the patient’s chest. Every few minutes, the device—powered by a battery with a lifetime of up to five years—generates a series of electrical pulses that lasts a few seconds.The pulses, typically a few thousandths of an ampere, are sent through a wire wrapped around the portion of the vagus nerve running along the left side of the patient’s neck. Pa- tients can also manually activate the device, using a switch operated