Over the last decade, the idea of machines that could be controlled by one’s thoughts has emerged from the realm of fiction to one of serious scientific inquiry.
The most common technical term for these types of devices is brain computer interface or BCI. Other synonymous terms include motor neuroprosthetics, direct brain interface (DBI), brain machine interface (BMI) and neurorobotics. Most simply put, these are machines that create a new output channel from the brain other than the natural motor and hormonal commands.
Brain computer interfaces recognize some form of electrophysiological alteration in the brain of a subject and use these changes as signals to either communicate with or control some element of the outside world that is consistent with the intentions of that subject. Concrete examples of such applications would be some type of brain signal controlling a cursor on a computer screen, a prosthetic limb or one’s own limb. These types of devices hold tremendous promise for improving the quality of life of individuals who are cognitively intact yet motor impaired. This includes patients with spinal cord injury, stoke or neuromuscular disorders, and amputees. These are patients for whom, up to now, the field of neurosurgery has not been able to offer any substantive intervention. Moreover, these populations are increasing in size and relevance because of the aging population and improved survival after stroke and trauma.
Now, with the improved understanding of the electrophysiological underpinnings of motor-related cortical function, rapid development of inexpensive and fast computing, and a growing awareness of the needs of the severely motor impaired, the notion of a practical and clinically viable BCI is beginning to deserve serious consideration. It will be essential for the neurosurgical community to understand what these devices are and their implications in regard to patient care. This will require a fundamental framework of how these systems operate, what the current BCI platforms and their limitations are, relevant issues when applied clinically, and discerning the important milestones for their evolution as they move toward entering standard neurosurgical practice.