MEDICAL IMPLANT TECHNOLOGY
From the humble beginnings of the cardiac pacemaker, medical implants have evolved into sophisticated devices capable of reciprocal interaction with the systems they manipulate. For the relationship between human bodies and technology, the possibilities a
Cyborg’ i s something of an evocative concept, conjuring images of futuristic space warriors with mechanical exoskeletons, or cackling supervillains who shoot laser beams from their eyes. The word, in fact, is short for ‘cybernetic organism’ – any living creature with mechatronic components.
Even more broadly, it’s a relationship between an organism and technology. So while, yes, space warriors and supervillains may be cyborgs, by these definitions, there are also many more realistic examples of cyborg technology all around us. Medicine is an obvious application, and current technology has one of two functions: to restore, or to enhance.
Restorative cyborg tech repairs bodily structures or processes that are broken or absent to restore an average level of function.
Enhancement technology, on the other hand, is the stuff of our fantasies: intervening to optimise performance or gain brand new function in what was, maybe, already a perfectly functional organism.
While many innovations already exist to enhance human performance, for the most part, mainstream medicine still focuses on restorative technologies through the installation of increasingly sophisticated implants. Here we look at a few implant devices: the fascinating, the common, and the revolutionary.
While you may not selfidentify as a cyborg because of your cardiac pacemaker (and that’s just fine), I’d argue that any integrated implant that responds to feedback from your body, does, technically, give you cyborg bragging rights.
COCHLEAR OCHLEAR IMPLANTS
The cochlea in the inner ear is the organ of hearing in humans. Sound waves enter the ear, are amplified by the ear drum, and then hit sensitive hairs in the cochlea that then send electrical signals to the brain.
For most deaf people, the hearing nerve that transmits the electric signal to the brain is intact, but the tiny hairs of the cochlea are damaged or missing.
A cochlear implant is a system that provides an entirely new mechanism for hearing. A microphone near the ear receives sound signals, and then a small external processor converts the sounds to digital information. This digital information is transmitted by an antenna to the part of the system that is surgically implanted under the skull. skull When the implant receives information from the processor, it sends electric signals down to an electrical array inserted in the cochlea. This stimulates the auditory nerve directly, sending sound information to the brain. The cochlear implant restores hearing by using simple technology to bypass the damaged inner ear and interact directly with the functional parts of the recipient’s hearing mechanisms. These ‘ bionic ears’ have been available since the 1980s, and more than 300 000 have been implanted worldwide.
IMPLANTABLE CANCER VACCINE
This one is not a mechanical device, and it’s not designed to restore lost function, but it is still an innovative, potentially revolutionary medical implant. A biomaterial-based cancer vaccine has been developed at Harvard University, utilising immunotherapy technology to stimulate the body’s own immune system to fight tumours. One reason tumours are so harmful is because they are made from our body’s own cells, so they are typically not recognised as dangerous or foreign by our immune system.
The implant is roughly the size of a Panado tablet. It is made from a biodegradable scaffolding that is infused with antigens (particles that induce an immune response) from the patient’s own tumour cells, as well as special stimulators that attract and activate immune- system cells called dendritic cells. The dendritic cells pick up pieces of the tumour antigens from the implant and carry them to the lymph nodes, the ‘command centres’ of the immune system. The implant essentially teaches the body that the tumour is a foreign object that must be eliminated. In ongoing clinical trials, scientists have demonstrated that the implant can shrink or eradicate multiple types of tumours, and it also shows promise in long-term protection against tumour recurrence. Just as with a disease such as chicken pox, when the body comes into contact with an antigen it has seen before, it springs into action to immediately destroy the threat.
DEEP BRAIN STIMULATION
Neural implants include anything that interacts with the electrical pathways of your own nervous system. Cochlear implants are one example, and another is a direct brain implant that provides deep brain stimulation to relieve the symptoms of Parkinson’s disease.
While it sounds like a particularly satisfying massage technique, deep brain stimulation is more akin to a ‘ brain pacemaker’ of sorts. Electrodes are surgically implanted in the brain through the top of the skull, and connected by wires running under the skin down to a battery-powered stimulator implanted into the chest. The stimulator sends electrical pulses through the leads to block the faulty signals which, in Parkinson’s patients, would otherwise cause tremors, rigidity and slowness.
This technology has been around for a couple of decades, and it reduces symptoms in most recipients. However, there are certain limitations that new technology is just beginning to address. Earlier this year, researchers revealed an ‘adaptable’ deep-brain- stimulation implant. Rather than the device being programmed externally by a doctor, this new implant can read and respond to signals from the brain by itself. This closed-loop system fine-tunes itself to deliver the exact level of stimulation needed to block faulty signals. This extends the battery life of the device, because it is no longer always firing at maximum capacity, delaying invasive replacement surgery down the line.
It also minimises the involuntary movements often caused by overstimulation, and is as effective as traditional deep brain stimulation at controlling tremors and stiffness. The technology empowers patients to regain physical ability and a better quality of life.
Transmitter Speech processor Receiver/ stimulator Microphone Electrode array EAR WITH COCHLEAR I MPLANTABOVE: The cochlear implant bypasses a damaged inner ear to restore hearing through direct stimulation of the auditory nerve.
ABOVE: Battery-powered electrodes stimulate particular parts of the brain to reduce symptoms in people with Parkinson’s Disease and other neurological disorders.
ABOVE: Tablet-sized implants teach the immune system to recognise cancerous tumours as a dangerous foreign object. DEEP BRAIN STIMULATION Lead Skull Lead wire Brain Brain Extension Electrode Subthalamic Nucleus Neurostimulator