What is it?

According to Wikipedia, biomedical engineering is:

"the application of engineering principles and techniques to the medical field. It combines the design and problem solving expertise of engineering with the medical expertise of physicians to help improve patient health care and the quality of life of healthy individuals." (remember this last part here; it's important!)

And this is applied how?

Besides clinical devices, such as MRI scans, biomedical engineering is also responsible for numerous medical devices. Hip replacements, artifical hearts, pacemakers, and even dentures. Beyond the now generally common, new advances in the field have lead to neural prosthics...

What are Neural Prosthetics?

Neural Prosthetics is an area of neuroscience aiming to repair or improve the nervous system with artifical devices. Such devices can be broken down into three catagories:

1. Auditory and Visual Prothesis
2. Functional Neuromuscular Stimulation (FNS)
3. Prosthetic Limb Control (via implanted neural interface)

Audio and Visual Prosthetics

Audio Prosthetics, such as cochlear implants (aka the Bionic Ear), are currently the most successful. This implant works by directly stimulating audiotry nerves.



As for Visual Prosthetics...

You know those tiny little dots you see after rubbing your eyes?

Those dots are actually phosphenes (a chemical which originates in the brain and is responsive to electrocortical stimulation). Scientist hope to stimulate patterns of phosophens which can then be interpreted by the 'user.' This would be achieved by implanting electrodes into the visual cortex of the brain. Progress is slow though, patients can see simple light patterns and make out crude letters. Such prosthetics include up to 100 microelectrodes permanently implanted in the visual cortex along with other external signal processing micro-electronics.

Functional Neuromuscular Stimulation (FNS)

Still in experimental use, FNS is an implanted electrode combined with an external battery-powered microprocessor used where spinal cord damage or a stroke has severed the link between the brain and the nervous system. The hope of these systems is to restore movement in legs, arms, and hands.

Neural Interfacing of Prosthetic Limbs

A prosthesis is an articial device typically used to replace (keyword!) a missing body part, the next step is to control these devices directly through the nervous system. Scientist are now making progress on neural interfacing, that is, implanting a microelectrode array chip in the path of a severed nerve. The nerve will regenerate through multiple holes on the chip. The chip is capable of recording from and stimulating peripheral nerves.

Though most research is still preliminary, the future of such interfacing is to provide a direct interface to prosthitcs and to also create a direct human-computer interface.

Time for an ethics check!

This technology is generally greeted with excitement and acceptance. Science historian, Donna Haraway suggests that the disabled are the first to praise neural prosthetics. Certainly, there are positive aspects to those who chose to benefit, the joy of hearing again, or getting back mobility in once lifeless limbs. Even preliminary studies show methods such as FDS can greatly benefit blood circulation and muscle regeneration.

However, beyond the material and physical hurdles (scientist struggle to find materials that the body's immune system will not destroy, as most materials deteriorate over time left inside the body), there are other ethical questions that arise:

Some argue that such technologies give unreasonable expectation to the injured. Others argue that societal ideas of 'handicaps' are not handicaps at all (i.e. being born deaf- "everyone wants a slice of the pie, but the pie is rotten!"). Furthermore, the majority of neural prosthetic studies have total dependence on laboratory animals (millions of animals are tortured and killed each year).

Now remember that quality of life part? Patients must undergo several life threatening operations to implant and maintain these devices. Besides the physical strain this causes a person, and the enormous medical bill it creates (up to and beyond the $100,000s, a lifetime on medications and currently a dependance on batteries), it directly violate the first rule of the Hippocratic oath "do no harm."

Not to mention, Neural Prosthetics are big business!



But lets cut to the quick:
Should engineering principles be applied to medicine?

So lets just drop that whole 'medical' thing...

Should humans just be cared for like machines?



"... the body is mass produced but at the moment it doesn't have any replaceable parts. OK, we're making artificial organs. But this is just a medical approach. What we really need is a design approach. If you have a heart that wears out after 70 years, this to me is an engineering problem. We should start to re-engineer the body."

-Stelarc

Take that proverbial can of worms! This would assume death is a flaw.

Further Reading

Science Daily article: Researchers Develop Neural Prosthesis Allowing A Monkey To Feed Self Using Only Its Brain

Two Articles: NEW TECHNOLOGY AIMS AT RESTORING LOST MOTOR FUNCTION and CUTTING EDGE—A CLOSER LOOK AT MULTI-ELECTRODE ARRAYS

FDA Risk/Benifits of Cochlear Implants

Second Sight Official Site, the leader in Visual Prosthetics

Yiannis Melanitis interview of Stelarc

An interesting chapter from Donna Haraway, "A Cyborg Manifesto," very philosophical.

A little side on non-vital organ transplant, Matthew Scott and his transplanted hand.