The Brain-Computer Interface
The mechanism of the BCI can be broken down into the following steps. First, the user visualizes performing a specific simple task, such as moving their right hand. The brain emits specific signals associated with the intent which in this case involves moving the right hand . This electrical activity is measured in voltage differences using an Electroencephalogram, or EEG technology, and is filtered and amplified . Then, a computer interprets the signal and learns the brain patterns associated with moving the right hand. Lastly, the computer software is programmed to recognize this specific pattern so that a certain action will execute every time the user visualizes moving their right hand.
How EEG Works
The locations of the electrodes each have their advantages and disadvantages. The skull is a medium that obstructs and distorts the electrical signals from the brain. Therefore placing electrodes on the skull’s interior, immediately on the exposed surface, is more effective since the signals will be measured directly . This practice is specifically referred to as Electrocorticography (ECoG). The disadvantage to this technique is that the procedure to implant the electrodes onto the patient’s brain is invasive. Any invasive procedure comes with complications. In this case the patient risks scarring brain tissue, which may obstruct the measurement of their electrical activity. This would defeat the whole purpose of placing the electrodes on the surface of their brain. The placement of the electrodes on the patient’s scalp is the preferred method since it is non-invasive. The patient typically wears an electrode embedded cap, which is attached to the head using a conductive gel.
The Thought-Controlled Wheelchair
Another thought-controlled wheelchair is also being developed at the Federal Institute of Technology in Switzerland. This wheelchair comes with two webcams that process visual information. The feature that distinguishes this wheelchair from Toyota’s wheelchair is that it uses shared control. Shared control means that the wheelchair takes in commands from the user as well as the webcam software . Essentially, the computer software exists to complement the user’s commands so that the user does not have to continuously control the wheelchair in the same direction. For example, the user will command the wheelchair to move in a certain direction. The software will then take over to evaluate and navigate the surrounding area to avoid obstacles in its path. This technology has an override command in the case that the user wants to approach an object instead of steering clear of it . This wheelchair has yet to be tested on paralyzed patients.
The Future of the Thought Controlled Wheelchair
-  Nijboer. “A P300-based Brain–computer Interface for People with Amyotrophic Lateral Sclerosis.” Clinical Neurophysiology, vol. 119, pp. 1909-916, 2008.
-  T. H. Maugh II. “Paralysis More Common than Thought.” Los Angeles Times (March 2011). Internet: http://latimesblogs.latimes.com/booster_shots/2009/04/paralysis-more-common-than-thought.html, [April 2011].
-  “Paralysis Population Survey Shows Over a Million More Paralyzed Than Previously Estimated; Five Times More People Live With Spinal Cord Injury and Disease.” Transverse Myelitis Association. Available: http://www.myelitis.org/newsletters/v9n1/newsletter9-1-10.htm, April 18, 2010, [May 02, 2011].
-  Cincotti et al. “Non-invasive Brain-computer Interface System: Towards Its Application as Assistive Technology.” Brain Research Bulletin[i/], vol. 75, pp. 796-803, 2008.
-  E. Grabianowski. “How Brain-Computer Interfaces Work.” Howstuffworks. Internet: http://computer.howstuffworks.com/brain-computer-interface.htm, 02 Nov. 2007, [March, 01 2011].
-  A. Heining. “Toyota Develops Thought-controlled Wheelchair.” The Christian Science Monitor. Available: http://www.csmonitor.com/Innovation/Horizons/2009/0629/toyota-develops-thought-controlled-wheelchair, June 29, 2009, [March 01, 2011].
-  Toyota Central R&D Labs, Inc. Genesis Research Institute, Inc. “Real-time Control of Wheelchairs with Brain Waves.” RIKEN. Toyota Motor Corporation, Internet: http://www.riken.go.jp/engn/r-world/info/release/press/2009/090629/index.html, June 29, 2009, [March 01, 2011].
-  D. Graham-Rowe. “Wheelchair Makes the Most of Brain Control.” Technology Review:The Authority on the Future of Technology. Internet: http://technologyreview.asia/biomedicine/26258/, Sept. 13, 2010, [March 01, 2011].