ESOF2008: Brain-computer-interfaces

This morning I attended a talk about the research behind, and clinical applications of, brain-computer interfaces (BCIs). I've written about BCIs many times in the past; they monitor the electrical activity of the brain, either invasively by means of implanted electrodes, or non-invasively by means an electroencephalogram cap, and this activity is analyzed and used to drive a peripheral device, such as a prosthetic limb, or a computer.

Nevertheless, it was an interesting talk, as it featured prominent researchers in the field, and included an application that was hitherto unknown to me. It was organized by Niels Birbaumer of the University of Tuebingen, and included talks by Eilon Vaadia of the Hebrew University of Jerusalem and Leonardo Cohen of the National Institute of Neurological Disorders and Stroke.

Abstract: A review of invasive and non-invasive brain-computer interfaces (BCI) in animals and human patients: BCI in complete paralysis and restoration of movement is described. Direct verbal brain communication in patients with complete paralysis proved the principle, particularly for locked-in patients with intact cognition. Detection of cognition in people without any motor output using event-related brain potentials demonstrate the feasibility of a "cognition" or lie detection system with invasive and non-invasive brain measures. Ethical implications are widespread, ranging from prolongation of life in paralysis, assisted suicide, artificial respiration and patient's declarations. Quality of life was found surprisingly high in complete paralysis. Restoration of movement with implanted electrodes allows execution of complex movement patterns with "pure thinking". Simple algorithms of neuronal cell population firing resulted in astonishingly high accuracy of direct brain-guided movement in monkeys. First data on human chronic stroke patients with positive results for hand movement restoration will be discussed. BCI-research, although in its infancy has produced excellent results in the laboratory and high hopes in the clinic.

BCIs are already being applied widely for all sorts of purposes. The user has to be trained how to use the device, such that they focus on controlling their mental activity to control the device more accurately. Thus, BCIs have already proven useful in children with attention deficit hperactivity disorder (ADHD), because this training leads to an inprovement in their ability to concentrate.

Other useful applications, which have already been demonstrated successfully, include detecting cognitive processes in patients who are completely paralyzed as a result of conditions such as amyotrophic lateral sclerosis (ALS), a form of motor neuron disease. Similarly, BCIs have also been used to show that patients in a coma and other similar conditions can be, as one of the speakers put it, "cognitively intact". So although it has long been thought that such patients are incapable of any thought processes, this is not the case.

Another application of BCIs is the facilitation of functional recovery and cortical plasticity in patients who have suffered chronic strokes. Patients who have suffered strokes can be trained with a magnetoencephalogram (MEG) to open and close their hands by means of a hybrid arm orthosis (or hand clamp) controlled by the BCI. Stroke is a major cause of disability, and so this particular application for BCIs has profound financial, medical and social implications.

All of this is now possible because the findings from experiments carried out in monkeys over the past 30 years or so now gives researchers the ability to make predictions about intentions, by detecting the activity of populations of neurons in the premotor cortex, which is involved in the planning of movements.

Training a patient to use a BCI is dependent on the brain's ability to adapt, as it involves actively focusing to increase the activity in a specific part of the brain. Another interesting application is therefore the modification of behaviour. An interesting example given in this talk was that of psychopaths. Neuroimaging experiments show that the regions of the brain which process fear are not engaged in psychopaths whilst they look at stimuli which would normally activate the fear circuits. BCIs have therefore been used to help train psychopaths to restore activity in those circuits, such that certain stimuli will elicit emotional responses. This has so far only been demonstrated exoerimentally, and it is unclear whether these findings will be useful outside of the laboratory.

For more about BCIs, here's a recent review by Birbaumer and Cohen about the use of the devices for restoring communication and movement in paralyzed patients, from the Journal of Physiology.