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September 17, 2005

Running on electricity

From: Times Online, UK - Sep 17, 2005

by Jerome Burne
New implant technology could transform lives and be a step towards real-life bionic people

Few of us would be without our miniaturised gadgets: camera phones, digital diaries and iPods. But the same technologies that enable such devices to insinuate themselves into our lives are also powering what may be an even more far-reaching revolution.

The lives of many people have been transformed in recent months after miniaturised devices were installed deep within their bodies. Electrodes the size of a grain of rice and batteries no bigger than a lighter can deliver tiny electrical currents to nerves that control the working of the guts, the movement of limbs and the firing of brain cells responsible for epilepsy, migraine and relentless headaches.

The technology holds the potential to relieve illness and disability. Some proponents believe that it also represents the early stages of the type of unification of flesh and silicon envisaged in science-fiction stories such as Blade Runner and The Six Million Dollar Man.

One of the beneficiaries of this emerging technology is Judith Walsh, an American whose entire left side was paralysed after a stroke. Intensive physiotherapy allowed her to speak and to walk again, but her arm remained atrophied. Last year, doctors at Northwestern Memorial Hospital in Chicago opened her skull and placed a patch the size of a postage stamp containing electrodes on the protective membrane covering her brain. This “bathed” the damaged area with electricity for six weeks. She can now make sandwiches, wash and dress her grandchild and drive a car.

As yet the experts are not clear exactly what the electrical impulses are doing, whether they allow nearby cells to take over the tasks of the damaged ones or enable the stroke-damaged tissue to regenerate.

While most of the pioneering research into implanting these electrodes is being done in the States, a handful of patients are receiving it in the UK. A nurse who had suffered constant inexplicable headaches for five years – “like hot needles on the side of my eye” – was one of 14 patients treated at the London Hospital, East London. She reported instant relief after implanted electrodes at the base of her brain sent pulses along nerves that reset the abnormal electrical firing in her brain. Her surgeon Laurence Watkins admits that he and his team don’t fully understand how it works, but suggests that “the impulses reset activity in a brain region that was causing her to respond as though pain signals were coming in even though there was no physical cause”.

Patients with severe intractable depression have reported “sudden calmness” and a “disappearance of the void” after implanted electrodes began stimulating their vagus nerve (an important nerve that runs from the brain to the abdomen) every five minutes with 30-second bursts of activity. In February, the American regulatory body the Food and Drug Administration granted a licence for this kind of treatment for people who had failed to respond to drugs or various types of therapy. It doesn’t work for everyone: about 20 per cent of 240 patients stopped being depressed, while 50 per cent reported feeling better. Doctors at the Institute of Neurology in London have so far tried it on four patients. One responded well, two reported a 50 per cent improvement in their symptoms and the fourth didn’t benefit.

Although still largely at the experimental stage, electrical implants have a history. Experimenters in the late 1700s found that they could make muscles twitch with static electricity generators. The cardiac pacemaker, which works by stimulating the heart with tiny electrical impulses, was first trialled 45 years ago and about 10,000 are fitted in Britain every year.

So we’ve known for a long time that the body is “on fire with electricity”, as the managing director of Medtronic, the leading manufacturer of implantable devices, memorably phrased it. But medical electrical technologies are now escaping from the shadow of microbiology and genetics, as it becomes clear that rapid bursts of low-voltage electricity can alleviate symptoms in many illnesses.

Obese patients have been able to control their appetite and lose weight with the aid of an implant that targets the other end of the vagus nerve (in the abdomen), while seriously affected epilepsy patients have had their seizure total drop from an average of 50 to 70 a month to 10 to 15. Already an estimated 30,000 people, nearly all in the US, have vagus nerve implants to help control their epilepsy.

The great advantage of implants is that they can relieve symptoms without the side-effects that plague most drug treatments for serious conditions. In the case of implants for epilepsy, for instance, the most serious side-effect seems to be hoarseness and a desire to clear the throat. Compare that with the dizziness, nausea and possible liver damage that accompany many commonly used drugs.

As microchips become smaller and more powerful, the possibilities expand. Already an American company, Advanced Bionics Corp, is testing a rechargeable electrical stimulator so tiny that it could be injected anywhere in the body to treat pain or muscle dysfunction.

Where is it all leading? The science writer Michael Chorost believes the hope isn’t just for new cures but for a revolution in our attitude to disability. With external aids becoming internal aids, people who would otherwise feel excluded from society are integrated.

Chorost’s book, Rebuilt: How Becoming Part Computer Made Me More Human, published by Houghton Mifflin in the States in June, tells how he suddenly lost all hearing in a single day but managed to climb back into the world of sound with the aid of a computer chip implanted in his skull just above the left ear.

Known as a cochlear implant, it converts sound waves into electrical pulses which are then sent to nerves in the inner ear and from there into the brain. It represents a step-up in sophistication from other implants because not only do the settings vary for each individual but the brain grows new pathways to accommodate the different patterns of impulses coming in from the implant. In a very real way the brain is being reformatted by the technology.

It’s here that you can see the first signs of a blurring of the boundaries between synthetic materials and flesh and bone that science- fiction writers have long been predicting. The current generation of electrical implants offers a lifeline to desperate people for whom medicine has nothing else to offer.

But some enthusiasts, such as the author and futurist Ray Kurzweil, see them as a forerunner of a time when we will go beyond implanting hardware into ourselves and turn our brains into silicon circuits.

Behold the body electric.

Current affairs

Electricity travels along all our nerve cells, allowing communication between different parts of the body.

Electricity is the natural product of having a membrane — a thin barrier — between two chemical solutions that carry a different charge. Each cell in our bodies is surrounded by a thin membrane and the differently charged metals sodium and potassium flow in and out of it. The result is a higher charge on one side of the membrane than on the other and that difference creates tiny amounts of electricity.

When the electrical firing of cells inside the brain goes wrong, one of the results can be epilepsy. Faulty firing of the heart’s electrical rhythms can be corrected by implanting a pacemaker.

Headache? Take eight electrodes ...

Patricia Eastman, who had suffered from terrible headaches for years, had electrodes implanted at the base of her skull by the neurosurgeon Laurence Watkins.

While she was sedated but still conscious, Watkins made a small hole at the base of her neck and with a canula (hollow tube) slid in eight electrodes attached to two fine wires. The electrodes, each about the size of a grain of rice, had to make contact with nerves that feed into the brain circuits involved in producing headaches. Not going into the brain directly makes the operation much safer.

Eastman had to remain conscious in order to tell Mr Watkins that she could feel a tingling sensation when he turned on the current, meaning that the electrodes were in the right place and working. Then she was put under general anaesthetic and the other ends of the wires were threaded under her skin, past the collarbone, to a specially made pocket of skin on her upper chest, which held a battery about the size of a cigarette lighter.

The operation is not widely available on the NHS and would cost about £25,000 if done privately.

Copyright 2005 Times Newspapers Ltd.