TECHNOLOGY EDGE: The Bionic Human Is Coming!

TECHNOLOGY EDGE: The Bionic Human Is Coming! | John M. Williams

Remember TV’s Six Million Dollar Man and Bionic Woman? Part human, part machine, these fictional cyborgs performed extraordinary feats. They had incredible strength, vision, speed, hearing, and leaping ability. While today’s cyborg technology may not provide people with disabilities these astonishing abilities, they may in a decade or two. The cyborg man or woman is coming, and people with disabilities may soon have an ally that puts them on equal ground with able-bodied individuals.

Meanwhile the technology is steamrolling ahead.

Cochlear Implants

Let’s look at the bionics of hearing—the cochlear implant. The cochlear implant provides a mechanism for hearing when a hearing aid is not enough. It is the only medical technology able to restore a human sense—hearing. Unlike a hearing aid that amplifies sound, a cochlear implant bypasses the damaged part and sends sound signals directly to the auditory nerve.

Here’s how the cochlear implant works: The outer ear and ear canal funnel sound inward to the middle ear, where the eardrum and three tiny bones vibrate from sound waves. In the inner ear, thousands of tiny sound receptors called hair cells in the fluid-filled cochlea sway with sound waves that send information to the auditory nerves, which transmit sound information from the hair cells up to the hearing center of the brain. A cochlear implant has two parts: an internal part, called the cochlear implant and an external part, called a speech processor. You cannot see the internal part because it is under the skin. One type of processor, a behind-the-ear model, is similar to a hearing aid and weighs only about 12 grams (less than a half ounce). Another type is the body- worn processor, the Sprint, which is about the size of a deck of cards or a small radio and weighs about 114 to 146 grams (4 or 5 ounces). It consists of the actual processor box and a small microphone worn behind the ear. A thin cable connects the microphone to the processor, which is ideal for infants and young children.

More than 50,000 people worldwide, ranging in age from 12 months to 93 years, have received cochlear implants and they are a proven medical option for people with severe to profound hearing loss in both ears. Recipients include people with cerebral palsy, developmental delays, learning disabilities, diabetes, high blood pressure, and tinnitus. A cochlear implant can cost $25,000 or higher. In Europe and Canada, the costs are covered by the government. In the U.S., most procedures are paid for by private insurance companies, Medicare or Medicaid. It is possible to receive an upgrade within a year or two after receiving a cochlear implant.

Bionic Leg

The bionic leg is for individuals whose leg has been amputated above the knee. Within three years, wearers will be walking up and down stairs, maybe jogging, but definitely dancing.

The leg includes a motor-driven knee and a complex system of sensors and microprocessors that gives the leg the uncanny ability to move and bend naturally. Locomotion is largely orchestrated by nerve cells scattered throughout the leg.

The result is an electrical relay race: The sensors transmit information to the microprocessor. The processor searches its dictionary to pick out a suitable walking pattern before sending instructions to the knee’s electric motor. The motor, in concert with the sensors and microprocessor, moves the leg in the same way that afferent neurons and leg muscles unite to choreograph movement. The motor acts as a muscle by moving the leg forward, unlike other prosthetic knees that require users to supply all the energy. The amputees can flex and bend their knees when climbing or traversing rocky terrain without having to twist the leg to raise it. There is, however, a drawback to the motor. It makes the leg rather heavy, which can be a problem for small users.

The price for a bionic leg is around $25,000.

Bionics Relieving Back Pain

Bionics has a role in alleviating chronic back pain. A chiropractor told me that half of all physicians’ office visits in the US are related to pain, creating an estimated economic cost to society of $100 billion annually, and afflicting approximately 70 million Americans. Half of all Americans suffering from chronic pain become partially, or totally, disabled.

Spinal Cord Stimulation, developed by Advanced Bionics, commonly called SCS, is an advanced pain therapy that has been used to control the perception of pain for decades. SCS delivers tiny electrical signals to your spinal cord to block pain signals. Stimulation is applied to your spinal cord using one or two very fine wires connected to a small implant. The stimulation reduces pain by creating a tingling sensation over pain areas.

One of the drawbacks of SCS is that the battery has to be charged and surgery is required for recharging. Recharges may be required once a year, but I could not get absolute confirmation on the frequency.

“The technology Advanced Bionics is introducing benefits the people who suffer from debilitating chronic pain and offers distinct advantages to the medical professionals who treat them,” stated Dr. John Oakley, neurosurgeon, Yellowstone Neurosurgical Associates in Billings, Montana. “Patients can use this device for a very long time before it needs to be replaced. More importantly, patients can be directly involved with their programming so stimulation can be steered to the precise neural population we need to target,” he said.

Hand Bionics

British scientists created the world’s first bionic hand, small enough to be used by a toddler. There are also bionic hands for adults.

Hand bionics work this way: The two motors that operate the hand are contained entirely in the thumb and forefinger. This allows the hand to be fitted to patients with half a hand. The unit is operated by signals from the brain. The user sends a signal to move a muscle in the forearm, and electrodes detect this and pass the message on to the motors. The bionic hand was made to grasp smaller objects, bicycle handles, hold paper cups, cut paper, open a candy wrapper, and throw. The cost of the procedure was not available at press time.

Bionic Eye

While the “bionic eye” is still at least five years away by most estimates, several prototypes of bionic eyes are making their presence felt by restoring sight to individuals with visual impairments.

Individuals with visual impairments are receiving sight through an artificial silicon retina solar-powered microchip developed by Optobionics. The microchips, surgically implanted behind the retina, are smaller than the head of a pin and about half the thickness of a sheet of paper. They work by converting light into electrical impulses.

“What we are doing is trying to replace the function of photoreceptors,” said Dr. Alan Chow, a pediatric ophthalmologist and chief operating officer of Optobionics. He developed the chip with his brother Vincent Chow, an electrical engineer. Chow found that the chips seem to be stimulating remaining healthy cells.

Implanting all the electronics, though, may prove to be a problem, since the eye is a corrosive environment where electronics don’t do too well. Certain materials, however, have been shown to be biocompatible and will exist in the body without major tissue reactions.

Chow’s devices, however, have not been shown to be biocompatible.

Loss of light-sensing photoreceptor cells occurs in retinitis pigmentosa and macular degeneration, the two most common causes of untreatable blindness in developed countries, affecting at least 20 million people worldwide.

There are other methods for replacing the retina. Working with individuals with visual impairments, researchers at the Keck School of Medicine of the University of Southern California are working on permanent “retinal prosthesis.” Participants lost their vision due to retinitis pigmentosa or age-related macular degeneration. They wore spectacles with miniature video cameras that transmitted signals to a 4-mm by 5-mm retinal implant, containing an array of 16 electrodes, via a wireless receiver embedded behind the ear. The signal is then re-created by stimulating the remaining healthy retinal cells with the electrodes, which pass on the information to the brain through the optic nerve.

Bionic research is also being done on other continents. For example, Australian researcher Nigel Lovell, from the University of New South Wales, is working on an implant with 100 electrodes, which he hopes will give patients the ability to differentiate between night and day, detect obstacles, and provide some rudimentary reading skills. “One hundred channels is near the practical limit,” said Lovell.

Bionic eye operations can cost up to $25,000 and some operations can be higher.

Neuroprosthetic Devices

Some researchers have used electrodes implanted in the brain or in the scalp, while others have experimented with detectors outside the body. But the basic idea behind neuroprosthetic devices is the same: creating communication between the brain and the outside object that needs to be moved. This technology has the possibility to change the lives of amputees or persons who have lost limbs or who are paralyzed. Some thought-driven devices being developed could eventually navigate wheelchairs, control robotic arm movement, or even move a computer mouse.

John M. Williams has been writing about assistive technology for 25 years. A sample of his book Assistive Technologies: Creating a Universe of Opportunities for People with Disabilities can be seen at www.atn-ctcf.org.