Fundamental Engineering for Brain-Computer Interfacing (BCI): Initiative for Neuron-Command Operating Devices

For many years people have speculated that electroencephalographic activity or other electrophysiological measures of brain functionmight provide a new non-muscular channel for sending messages and commands to the external world – a brain–computer interface (BCI) [4]. Over the past 15 years, productive BCI research programs have arisen [4]. Encouraged by new understanding of brain function, by the advent ofpowerful low-cost computer equipment, and by growing recognition of the needs and potentials of people with disabilities, these programsconcentrate on developing new augmentative communication and control technology for those with severe neuromuscular disorders, such asamyotrophic lateral sclerosis, brainstem stroke, and spinal cord injury [34]. The immediate goal is to provide these users, who may be completelyparalyzed, or ‘locked in’, with basic communication capabilities so that they can express their wishes to caregivers or even operate word processing programs or neuroprostheses [4]. Present-day BCIs determine the intent of the user from a variety of different electrophysiologicalsignals [4]. These signals include slow cortical potentials, P300 potentials, and mu or beta rhythms recorded from the scalp, and cortical neuronalactivity recorded by implanted electrodes [4]. They are translated in real-time into commands that operate a computer display or other device [4]. Successful operation requires that the user encode commands in these signals and that the BCI derive the commands from the signals [4]. Thus, the user and the BCI system need to adapt to each other both initially and continually so as to ensure stable performance [29]. Current BCIs havemaximum information transfer rates up to 10–25 bits/min [4]. This limited capacity can be valuable for people whose severe disabilities preventthem from using conventional augmentative communication methods [4].