A 'brain cap' may warn us of mistakes

The possibility that car drivers could one day wear a special cap to warn when they are showing dangerous lapses in concentration is raised today. Scientists have found that it is possible to tell if a person is likely to make a mistake up to half a minute before they are even aware they have made it. The discovery suggests that one day employees could monitor the brain of a person doing a monotonous but important task, such as monitoring nuclear plant safety, driving or piloting a plane, to improve safety. Human errors, according to Dr Tom Eichele of the University of Bergen, Dr Stefan Debener of the MRC Institute of Hearing Research, Southampton, and colleagues in Germany and the US, are not solely the result of momentary fluctuations in concentration or brain activity, as had previously been suspected, but due to the brain itself doing the equivalent of losing its focus on doing a task: it reveals a drift in attention. To detect this drift, the researchers used a kind of scanner method, functional magnetic resonance imaging, to study blood flow in the brain of subjects engaged in a flanker task, a classic psychology test in which a subject has to say if he can see, for example, a certain shape when surrounded by distracting shapes. The team reports in the Proceedings of the National Academy of Sciences that it found that a set of regions in the brain displayed altered activity up to 30 seconds before a subject made a mistake. These areas include a part of the brain's default mode network, located in a posterior midline cortex, which showed a gradual increase in activity as the brain became fatigued by a repetitive task. The authors noted that, simultaneously, brain activity also decreased in frontal brain regions associated with maintaining effort while performing a task before a mistake occurred. Once the subjects committed and detected their errors, they re-engaged in the task, and the activity pattern reset, according to the team, which is now studying what this pattern does in other circumstances, and how the new analysis method developed could be used in clinical research. As for using the method to monitor workers, that would require a cheap, lightweight and mobile alternative to the bulky scanners used for the experiment, says Dr Eichele. However, it might be possible to find corresponding patterns of electrical activity that can be picked up by scalp electrodes, a more old fashioned method called EEG (electro-encephalography). "In the EEG literature there are some reports that found error-preceding activity, but so far not longer than a couple of hundred milliseconds (thousandths) of a second or so ahead," says Dr Eichele, whose team is seeing if this simpler method can detect errors. There are already commercial brain caps in use for mind control of computer games - Emotiv Systems, from San Francisco, has developed EEG caps that use the electrical signals from a player's brain to control the on-screen action.