As people become increasingly ‘plugged in’ to the wired world, it’s not uncommon to hear people joke about being surgically-attached to their device of choice. The image at the heart of the joke is old; the idea of a fusion between man and the mechanical exists in folklore that predates the oldest computer — think of ancient Jewish stories of golems, or even the figure of Prometheus in Greek mythology. In the modern age, these stories were reintroduced through the figures of robots and cyborgs. Recent technology in the medical sciences has realized this interconnection between the electronic and biological in way that has the potential to be game-changing. Devices known as Brain Computer Interfaces (BCIs) could revolutionize limb replacement and prosthetics.
These interfaces, which are also known as Brain-Machine Interfaces (BMI), Mind-Machine Interfaces (MMI), or Direct Neural Interfaces (DNI), are devices that use signals from the brain to control electronics. The science behind BCIs is widely interdisciplinary, incorporating elements of psychology, biology, computer science, and engineering. They are most commonly researched by teams led by biomedical engineers and neuropsychologists. Prosthetics are devices that replace or supplement a non-functioning or absent body part. Neural prosthetics, or neuroprosthetics, are prosthetic devices which are controlled by electric signals sent by the body. These electric prosthetics can serve as a refinement of traditional artificial limbs — neuroprosthetic limb replacements are in development — but also include new technologies, like cochlear implants. Cochlear implants, also known by the slightly more sci-fi nickname ‘bionic ears,’ can provide some sense of hearing to people who suffer from severe hearing loss or deafness due to a damaged inner ear. Unlike traditional hearing aids, which simply amplify sounds so that they can be perceived, a cochlear implant bypasses inner ear damage to directly stimulate the auditory nerve.
Though the terms “BCI” and “neural prosthetic” are occasionally used interchangeably, BCIs are more accurately identified as a subtype of neural prosthetics. Whereas a neural prosthetic could technically be attached to any appropriate nerve cluster, a BCI is, as the name implies, connected only to nerve clusters in the brain.
The word “neural” in neural prosthetics literally means “of the nerves.” For humans, the nervous system is the system by which information is transmitted. Individual nerves are long strings of axons or fibres. These fibres are the appendages of neuron cells, specialized cells that can transmit information electrically to the network that is the human body. Scientists can detect these electrical signals and are capable of determining what information various signals carry.
BCIs work through the interaction of an electrode with a neuron cluster. These electrodes then interpret and send the electric signals from the neuron to the device. A neural prosthetic essentially connects the biological network with an electrical network; it represents a fusion of biology and hardware.
Though certain neural prosthetics, like the cochlear implants discussed above, are already in active use among the general population, the field is constantly expanding; new techniques and devices are rapidly developing. There is a noticeable progression in the field. In 2008, Nature reported that a team of researchers at the University of Pittsburgh had successfully implanted a complex BCI in two monkeys. The team, led by Andrew Schwartz, created a robotic arm designed to imitate realistic movement, and implanted electrodes in the monkey’s motor cortex. This area of the brain controls movement in mammals. After a training process, both monkeys were able to successfully manipulate a robotic arm to retrieve food and feed themselves when prevented from using their biological arms. The experiment was considered a success in part because of the dexterity the each monkey achieved with their BCI arm.
When Nature asked Schwartz about the possibility of testing his procedure on humans he was optimistic. “I think we’ll be doing this on an experimental basis in two years,” he said, though he did add that he believed it would take longer before the procedure would be tested on a person with disabilities.
In January of this year, Nature reported that Schwartz had led another research team in a project that implanted two microelectrodes into the brain of a woman who was paralysed in all four limbs. The electrodes were connected to a neural prosthetic arm. Less than two weeks after the surgery, the woman began training with the arm, and within 13 weeks could grasp and move objects at speeds comparable to a person without disabilities.
Schwartz’s work and other similar experiments represent the necessary first steps before medical science can achieve the wider application and adoption of bmi technologies and procedures. Though these developments represent a definite advancement of the science of bmis, complications result from the sheer novetly of these experiments. The relatively rapid emergence of new techniques might keep things interesting, but the development and refinement of these techniques present challenges. The systems themselves are quite delicate, and the procedures required to design and assemble neural prosthetics are complex. Beyond the engineering process, the surgeries that are required to properly install a BCI or neural prosthetic are complicated and require the utmost precision.
In turn, these factors contribute to the cost of the devices. Even the relatively established and proven cochlear implant costs around $24,000 for the hardware alone, and the procedure necessitates the inclusion of the additional costs of surgery and support personnel in the budget. The developers of experimental BCIs incur even more expenses on top of these costs.
BCIs are also not without ethical controversy. Some people with disabilities find the idea of BCIs or prosthetics designed to “correct” their disabilities to be fundamentally disrespectful. There are also those who question the morality of the procedure, especially given the possibility that a patient’s mood or personality might be adversely affected. bmi supporters counter-argue that it is common for medical procedures to have side effects and that some of these side effects are psychological.
Still, the debate over the ethics of BCIs does not overshadow the technological advancement that they represent. There are already whispers about the possibilities of commercialization: the idea that BCI research might one day lead to a discovery or technique that could be incorporated into personal computing or cellular technologies. But the prospect of a mind-controlled computer hardly measures up to a concrete BCI; an elegant fusion of biological and electronic networks that promises exciting developments in medical science.
