Imagine being able to control objects such as a robotic arm, a cursor, or a computer mouse with just your mind. With the technological advances occurring in the world, this is becoming more of a reality than just an idea. Now devices called BCIs are being created and studied to help benefit those that have neurological illnesses or are disabled. These devices aim to restore or replace useful function to people disabled by neuromuscular disorders. The future will bring faster, more reliable BCIs. BCI systems involve many different fields and studies. Two important fields required in BCI systems are neurology and Biomedical engineering. Neurologists focus more on the study of the brain when researching BCI systems while Biomedical engineers focus more on the technological advances involving BCI systems. When using these systems, neurologists will often use noninvasive BCIs to study components of the brain such as brain waves and electrical impulses while biomedical engineers will use invasive BCIs to try and advance the technology for easier use.
BCI, which stands for brain-computer interface, is a device that can decode human intent and thoughts from brain activity to direct some external activity, such as control a cursor or a prosthetic limb. Essentially these systems receive the input of brain signals and use complicated recognition algorithms to create devices. These devices allow for a direct communication pathway between the brain and the object to be controlled. For this, no actual movement of the body is required. BCIs can be used for communication, computer access, or control of devices such as a wheelchair or prosthetic arm. Almost anything a computer can control, potentially, can be controlled by BCIs. BCIs are being studied and used as a rehabilitation device to help people regain motor skills and as a prosthetic device to replace motor skills that will never be able to return. There are two types of BCI systems: invasive and noninvasive. Invasive systems require surgery to implant electrodes on the brain while noninvasive BCIs are placed on the scalp and held in place with a cap and gel. Noninvasive systems usually involve using Electroencephalograms(EEG) to read brain signals.
An important aspect of brain-computer interfaces is the study of the brain. It is very important to know how the brain works and how messages move through the brain before discussing BCI’s. The human brain is ultimately responsible for all thoughts and movements that the body produces. The brain is made up of nerve cells which interact with the rest of the body. When we talk about signals and messages being sent from the brain or to the brain, we’re talking about electricity carrying messages. These electrical messages are passed throughout the brain and body by cells called neurons. These cells are the core component of the brain and there is an average of about 100 billion neurons within the brain. Information transmission within the brain is only successful with the combination of electricity and chemicals.
Before looking at the two different disciplines, it is important to look at the purpose of the two careers and how they approach BCI systems. Neurology is the branch of medicine that studies and treats disorders that involve the nervous system. Neurologists are the medical doctors that treat and study disorders that affect the brain, spinal cord, and nerves. They do not perform surgeries and if a patient requires surgery, then they refer them to a neurosurgeon. Neurologists also monitor patients that have had surgery and oversee patients’ continuation of treatments. These neurologists also study patients’ past medical histories and conduct tests to determine problems in the nervous system. With the common aim of helping others, biomedical engineering is the application of engineering principles and concepts to medicine and biology for healthcare purposes. Biomedical engineers will analyze and design solutions to problems in biology and medicine to try and improve patient care. These engineers work with a number of different field workers such as doctors, therapists, and researchers to develop equipment and devices. At research institutions they do extensive research, supervise laboratories, and participate in or direct research in collaboration with other researchers with backgrounds in medicine, physiology, and nursing. Even though these two fields are different, there are times when workers from these will come together to work on different types of projects. The difference between the two when using BCI systems are the types that they use. Neurologists will generally use noninvasive BCI systems as they are used more for research purposes while biomedical engineers use invasive BCI systems to try and further advance the technology used. However noninvasive and invasive BCI systems are still used in both studies.
When using BCI systems neurologists aren’t as concerned about the technological advances, as they focus more on the study of the brain and how it functions. The main reason neurologists use noninvasive systems is because it involves no surgery. The noninvasive BCI systems that they use usually involves EEG. These are by far the most widely used BCI technique because it is cheap and portable. EEG as well as MEG(magnetoencephalography) is used to study brain signals and reflect the average activity of dendritic currents in a large population of cells. The temporal resolution of EEG and MEG to measure changes in neuronal activity is high; however, the spatial resolution to determine the precise position of active sources in the brain is poor. The components that neurologists study when using BCI systems involve brain waves, electrical impulses, neuron activity, and magnetic fields. Research areas include measurement of brain-activity and evaluation of brain-activity that can be used for communication. Using these systems has led to substantial progress in understanding and deciphering the neural code of the brain. An example of this would be the work done by Brodersen and collaborators who used a computational model of neurodynamics to improve decoding. Even though they are still very far from decoding the brain as a whole, with BCI systems neurologists are getting ever so close.
One example of using BCI for neurological studies is the Kübler and Kotchoubey experiment. This line of research used BCI techniques to better diagnose non-responsive patients and, possibly, to communicate with those in a minimally conscious state. The BCI system used in the study allowed patients to select letters, words or items on a computer screen for neuroprosthesis control. Another example of using BCI for studying the brain would be the Sellers’s and Donchin’s original experiment. Sellers and Donchin used a four-choice paradigm and tested their system with three subjects suffering from ALS and three able-bodied subjects. From their research they showed that communication is possible in the visual and auditory part of the brain. The research also showed the difference in brain activity between able-bodied subjects and disabled subjects. In the brain of the disabled, there were certain parts of the brain that no longer functioned or was able to communicate with the rest of the body effectively.
For biomedical engineers, they approach BCI systems in a different matter; they focus on making more technological advances. They more often use invasive BCI systems because it gives a more accurate and clean signal for them to analyze, seeing if the machine is working effectively or not. Since invasive BCIs involve implanting electrodes into the skull, most of these studies are done on animals. However, noninvasive BCI systems are still used to try and advance technology. One example of biomedical engineers using a BCI system to create more effective technology was a study(from a scholarly article) used to analyze ankle movement. This research dealt with five-able bodied subjects that performed ten alternations of idling and repetitive for dorsiflexion. The results of this research showed that it is possible to create BCI systems that apply to lower extremities of a humans’ lower body. With this, BCI systems can be used to restore lost motor functions that were due to neurological injury.
BCI systems are creating a major impact on the disabled. These devices are allowing patients to assist, augment, or repair human cognitive or sensory-motor functions. BCIs are also allowing the able-bodied to connect to external devices for usage such as computer typing, controlling a computer cursor, or even making a balloon shark swim in the air. BCI systems are used in different fields and are approached in different ways. Neurologists use noninvasive BCIs to study neurological or brain activity while biomedical engineers test invasive BCI systems to further advance the technology that is used in these types of systems. Overall, even though these systems are still in its infancy, BCI systems hold great promise to be particularly helpful to people who are severely disabled such as amputees and those with neurological diseases.
References
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Ulrich Hoffmann, Jean-Marc Vesin, Touradj Ebrahimi, Karin Diserens, An efficient P300-based brain–computer interface for disabled subjects, Journal of Neuroscience Methods, Volume 167, Issue 1, 15 January 2008, Pages 115-125, ISSN 0165-0270, http://dx.doi.org/10.1016/j.jneumeth.2007.03.005.
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Do, An, Po Wang, Christine King, Ahmad Abiri, and Zoran Nenadic. "Brain-Computer Interface Controlled Functional Electrical Stimulation System for Ankle Movement." Journal of NeuroEngineering and Rehabilitation (2011). Biomedcentral. BioMed Central. Web. 3 Dec. 2015.
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