|
As a clinician, this news is extraordinarily exciting. Here's why. A brain computer interface is something that records neural activity in a person, and then decodes that neural activity to allow them to control objects in their environment. When we think about sources of neural information, it's useful to divide them into non-invasive (EEG, fMRI, MEG, NIRS) technology, and to invasive technology (intracortical electrodes, SEEG, ECoG) systems. Fundamentally, the DARPA grant is about acquiring new sources of neural information. As the article points out, the latter category is happening almost exclusively as people are hanging out in epilepsy monitoring units with nothing better to do, or as part of early clinical trials looking at safety profiles of implanted devices. Simply speaking, the divide between invasive and non-invasive systems is about the signal-to-noise ratio of neural information. The closer you get to single neurons, the closer you get to the source of neural activity, the higher the signal quality you get to decode with. Consider that EEG systems (the most commonly used non-invasive methods) average neural activity over the range of several 10^-3 to 10^-2 meters, through the attenuation of spinal fluid, dura mater, skull, five scalp layers, and the electrode interface. Electrodes used in modern intracortical BCI systems are 10^-5 meters in diameter. To my mind, the DARPA announcement is extraordinary -- these technologies have the possibility of upping the SNR for non-invasive methods, and acquiring fundamentally different sources of neural activity. Importantly, the methods seem to have the ability to work at the bedside, without needing very large and very expensive devices (e.g. fMRI, MEG). Here are some reasons why this would be important: 1) Someone has been admitted to the intensive care unit, and needs a breathing tube on a ventilator for life saving purposes. Some people in this situation are awake and alert. Literature suggests that being intubated and awake is incredibly scary, since you're aware but can't communicate. Having a non-invasive beside method that could decode your thoughts would be a dramatic increase to the person's quality of life, given their temporary stay. Note that eye-trackers may not be feasible, given the amount of stuff in the ICU room, the fact that they're lying down, etc. 2) If you ask people with locked in syndrome them about their priorities for improving their quality of life, the biggest need is improving their ability to communicate (as opposed to spelling boards, or looking up/down to communicate). Note these people cannot use eye-trackers, due to their neurologic condition. 3) Ongoing clinical trials have had volunteers undergo implantation of electrodes into their brain. The devices implanted have been percutaneous (i.e. had a portion go through their skin). These devices have allowed some participants to feed themselves, either using muscle stimulation or through robotic arm control. Not only would having a non-invasive method obviate the need for a surgery, but having a method for "writing into" the brain would provide closed-loop control of the arm/robotic limb they were controlling, putatively increasing the quality of control. |