Rebuilding The Human Body

I often post articles relating to medical technology, but today I’m going to focus on just those technologies that are available or being researched now that can be implanted into (or onto) humans. Specifically, I am going to talk about several new technologies that promise to restore (and one day replace) faulty biological systems. We will start at the top.

Eyes:

Scientific American reports that scientists have created a retinal implant that can restore sight to some of the blind. Light-detecting cones (called photoreceptors) in the eyes that malfunction cause some forms of blindness. By implanting a tiny 3mm x 3mm chip at the back of the eye, the device can act as artificial photoreceptors and transmit the light that the failing biological photoreceptors no longer do. This implant has been tested on humans (a continuing trial has expanded to five additional cities) but the implant still is not perfect. For one, it requires an external power supply (which sits behind the ear in this model.) For another, only a “narrow field of vision” is restored. Several other companies are also working on solutions.

Already, however, upgrades are in the works. Technology Review reports on a new light-powered implant that promises to remove the external power supply while also granting a much clearer and wider field of vision. However, this device requires relatively bulky external glasses to function (as does another device set for testing next year.) Based on Kurzweil’s exponential predictions, we can expect these devices to double in power and shrink by half in size roughly every two years. By 2020, these devices may very well be fully implantable into a skull, completely replacing the faulty eye.

Not only could one replace the eye, however, the implant could have additional functionality. For instance, Fox News reports on new contact lenses in development for the Department of Defense that offers Heads Up display (HUD) technology in addition to other virtual reality and augmented reality solutions. Other devices, including drones, could transmit real-time battlefield information to each soldier’s implants, giving a true bird’s-eye view of the battlefield and increasing situational awareness immensely. Since this technology is already quite small, integrating it into a false-eye instead of a contact lens ought not to be a very difficult prospect. Of course, this technology is valuable outside of the military as well, so regular folks ought to get a more immersive video game experience and be able to access technology-enhanced vision for their own uses too.

 

Chest:

The eyes are hardly the only organs we can replace; scientists recently implanted an artificial, and pulseless, heart inside a man. Instead of a pulsing supply of blood like a regular heart provides, the new heart supplies a continuous stream of circulating blood.  Although the blood vessels, veins, capillaries, and other blood-transferring structures still limit the force with which blood can be circulated, presumably a device like this could increase blood flow on command when a person is engaged in strenuous activity (and without having to get one’s ‘heart racing’ beforehand.)

Not only is the function of the heart being improved upon, but also scientists have recently created the lightest artificial heart and implanted it into a baby. Doctors in Rome replaced a 16-month old baby’s failing heart with a device that weighs a mere 11 grams (the normal adult heart weighs more than 300 grams.) Further, this device has already gained FDA approval, and so is ready for transplantation into other patients.

Perhaps one way to use these continuous-flow devices is to propel tiny devices for surgery or, later, for delivering drugs and maintaining the general health of our bodies. Scientists at Stanford have invented one such device. This tiny device can move through blood vessels and other parts of the body at the doctor’s direction, cleaning out blood clots and the like. This device has some way to go before it is ready for clinical trials, but does provide proof of concept now.

Arms:

Prosthetic arms have been progressing nicely for several years now (see my Deus Ex article, for instance.) Just recently, however, there have been a number of really exciting improvements in prosthetic arms.

Traditionally (if such a word is appropriate in this sort of fast-moving field) prosthetic arms operate through sensors on the inside of the prosthetic that monitor electrical signals traveling to whatever is left of the patient’s limb; an arm severed above the elbow, for instance, still has muscles that run to the point where the arm was amputated and the sensors detect electrical signals through the skin at the end of the arm. This allowed crude movement at first, and more fine motor control later as the number of sensors increased. There was, however, no sense of feeling in the limb. Now, however, scientists in Vienna have found a way to replace some nerves that originally controlled hand and arm movement and have relocated those nerves to the chest; now the patient, British soldier Andrew Garthwaite, will be able to ‘feel’ through his prosthetic arm when sensors in the arm transmit data to the nerves now relocated into his chest. The movement of nerves ought to also make control of his new arm more fluid and natural. See this video from the BBC:

DARPA (the Defense Advanced Research Projects Agency) and other agencies are trying to improve upon this technology even more by promoting further nerve growth and more feeling in limbs. Wired magazine also has an article describing the technical challenges; the need for polymers that are inoffensive to biological tissue, yet are conductive and strong.

Finally, whether fitted with a prosthetic limb or not, a direct user interface can be implanted under your skin to control other implants (perhaps some of those for bionic eyes, say.) Controlling other implants is going to have to be done manually, though there are several ways to do that. Some, for bionic eyes, could rely on tracking the user’s field of vision to select icons imposed in the field of vision simply by focusing on them for a moment. Others, like for bionic limbs currently, must be pressed manually. The circuit board in the article provides additional functionality, including audio, touch input, and vibration feedback. Of course, ideally limbs could be controlled by thought alone, though we are some way from that. Researcher Albrecht Schmidt says, for instance: “You can also extend social networks into your body — be connected with others with implants, feel pulses of vibration from others,” he added. “This can get very personal… it’s a way of letting someone under your skin.”

 

Legs:

Prosthetic legs has also been making progress, though there currently seems to be a divide between prosthetics that replace legs (like those mentioned in the previously linked Deus Ex article) and bionic systems that connect to the legs on the outside and provide more functionality.

Esko Biotics recently sold its first pair of these latter types of legs. This system is not an implant, but instead an exoskeleton. This exoskeleton moves the limbs of those whose spine no longer allows the patient to control their own limbs. This is important because not all leg conditions could be solved via implant; it is not that there is anything wrong with a paraplegic’s legs, per se, but instead with the nerves that control them. A bionic apparatus like this, then, provide benefit where simply replacing the legs would not.

KurzweilAI.net reports on a similar exoskeleton that uses a skullcap to read electrical signals from the brain, and then translates those electrical signals into exoskeleton movements for the patient’s legs. This system bypasses the faulty nerves and directly controls the legs very like what an undamaged nervous system would do. However, the signals that reach the scalp and are captured by the cap are not very precise; certainly not as detailed as the original signals. A direct brain-machine interface (or BMI) would be better, but involves currently risky surgery and tinkering with the brain; an always dangerous endeavor.

See the following video for an inspirational video about a paraplegic who completed a marathon (though a number of improvements would be ideal):

For some more implant news, check out this BBC feature that highlights a couple of additional technologies: Can You Build A Human Body?

I will conclude with one last quote from Albrecht Schmidt, who I think captures the moment perfectly: “We’re at a point where implants may become something quite normal,” Schmidt said. “This work will open up discussion as to whether we get implants not for a medical reason, but for convenience.”