Brain-computer interfaces in medicine

Abstract

Brain-computer interfaces (BCIs) acquire brain signals, analyze them, and translate them into commands that are relayed to output devices that carry out desired actions. BCIs do not use normal neuromuscular output pathways. The main goal of BCI is to replace or restore useful function to people disabled by neuromuscular disorders such as amyotrophic lateral sclerosis, cerebral palsy, stroke, or spinal cord injury. From initial demonstrations of electroencephalography-based spelling and single-neuron-based device control, researchers have gone on to use electroencephalographic, intracortical, electrocorticographic, and other brain signals for increasingly complex control of cursors, robotic arms, prostheses, wheelchairs, and other devices. Brain-computer interfaces may also prove useful for rehabilitation after stroke and for other disorders. In the future, they might augment the performance of surgeons or other medical professionals. Brain-computer interface technology is the focus of a rapidly growing research and development enterprise that is greatly exciting scientists, engineers, clinicians, and the public in general. Its future achievements will depend on advances in 3 crucial areas. Brain-computer interfaces need signal-acquisition hardware that is convenient, portable, safe, and able to function in all environments. Brain-computer interface systems need to be validated in long-term studies of real-world use by people with severe disabilities, and effective and viable models for their widespread dissemination must be implemented. Finally, the day-to-day and moment-to-moment reliability of BCI performance must be improved so that it approaches the reliability of natural muscle-based function.

Copyright © 2012 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.

Figures

FIGURE 1

Brain-computer interface articles in the peer-reviewed scientific literature. Over the past 15 years, BCI research, which was previously confined to a few laboratories, has become an extremely active and rapidly growing scientific field. Most articles have appeared in the last 5 years. BCI = brain-computer interface.

FIGURE 2

Components of a BCI system. Electrical signals from brain activity are detected by recording electrodes located on the scalp, on the cortical surface, or within the brain. The brain signals are amplified and digitized. Pertinent signal characteristics are extracted and then translated into commands that control an output device, such as a spelling program, a motorized wheelchair, or a prosthetic limb. Feedback from the device enables the user to modify the brain signals in order to maintain effective device performance. BCI = brain-computer interface; ECoG = electrocorticography; EEG = electroencephalography.

FIGURE 3

Intracortical microelectrode array and its placement in a patient with tetraplegia. A, The 100-microelectrode array on top of a US penny. B, The microelectrode array in a scanning electron micrograph. C, The preoperative axial T1-weighted magnetic resonance image of the patient. The red square in the precentral gyrus shows the approximate location of the array. D, The patient sitting in a wheelchair and working with a technician on a brain-computer interface task. The gray arrow points to a percutaneous pedestal that contains the amplifier and other signal-acquisition hardware.