14th March 2013 Toronto, Canada
Scott and the Machine
This is a guest post by Dr. Srivas Chennu of the University of Cambridge, a nueroscientist who visited Canada last year as part of a SIN project.
Scott and the Machine: International collaborations in the study of disorders of consciousness
It was a busy 2012 for Scott Routley. For a while last year, he shot to fame as science media reported on his remarkable case. Scott, they said, had “spoken” for the first time in the 12 years since a car accident left him in an apparently vegetative state. Based at the University of Cambridge, I am a part of the international team of scientists here and in London (Ontario) that devised a way of “seeing” what Scott was trying to “say”. Though Scott couldn’t actually speak, we put him in a brain scanner and asked him to imagine specific thought actions, like playing tennis, to answer a series of questions. What we saw was remarkable: Scott was reliably able to do what we asked of him, and even tell us that he was not in pain.
In typical medical circumstances, doctors assess that a patient is conscious after brain injury by the fact that they are able to use their body or their voice to respond consistently. Scott is rare, but certainly not unique, in the ability to use his brain activity, but not his body, to communicate with the outside world. To be sure, the form of interaction Scott engaged in was extremely limited and very slow. Furthermore, it required him to lie perfectly still in an extremely expensive superconducting magnet that could see inside his brain. But it was the first time, in over a decade of being diagnosed as effectively unaware of anything, that he let us know that he was in fact conscious.
Last summer, funded by the Science and Innovation Network, I traveled to Canada with the aim of jointly developing tools that might one day enable people like Scott to communicate from their bedside. Around the same time, Scott was being filmed extensively for the making of a groundbreaking BBC Panorama documentary about patients in such states, collectively called disorders of consciousness. Incredibly, the film crew managed to capture Scott’s rare achievement on camera. The hour-long documentary followed individual patients in the UK and Canada through their journeys, highlighting the exceptionally unique and trying circumstances that they and their families find themselves in. Accurately diagnosing the true level of awareness of patients like Scott has always been challenging, and the documentary made it clear that new techniques employing brain scanning could play a valuable role. However, precious few such patients ever see the inside of a brain scanner. The lack of portability, significant expense and physical limitations mean that scanning the brain of every patient is unlikely to be feasible in the foreseeable future.
Instead, I believe that techniques that measure changes in brain waves, called electroencephalography (EEG), hold the key to helping a vast majority of patients with such disorders. EEG is completely painless, and unlike brain scanning, can be recorded at the bedside with relatively inexpensive equipment. EEG does not have the fine-grained detail and quality that brain scans provide, but for many patients it could provide valuable first insights early in their journey. What’s more, specially devised tests can use EEG to probe brain function at successive levels of depth and complexity, without ever relying on the patient to respond with their body. At the highest level of such complexity, EEG was even able to detect awareness in Scott, confirming what we saw in the brain scanner.
Over my time in Canada, this was what kept me busy. I worked with Dr. Damian Cruse and Prof. Adrian Owen, to develop and prototype software that will detect, in real-time, whether or not a patient is performing thought actions on command. This so-called Brain-Computer Interface analyses EEG recorded by electrodes placed on the patient’s scalp, and learns to identify patterns that correspond to specific thought actions, like imagined movements of limbs. The statistically reliable detection of such patterns would indicate that the patient is responding to commands to perform these imaginations. Based on tests of the prototype with healthy individuals, I confirmed that it worked well, albeit in a controlled laboratory setting. If this system could be made robust enough to detect Scott performing thought actions, he could possibly also use it to communicate, by selecting one amongst a pair of imaginations to answer yes or no to a question. But what I started remains unfinished business: Before we can test our prototype with patients, we need to road test it thoroughly. The stakes are high: If a patient is in fact following our commands then we need to be as sure as possible that we will be able to detect it. At the same time, we need to make sure not to cry wolf when there is no evidence of awareness. With noisy, and in some cases unreliable, data this can indeed be challenging.
Nevertheless, I hold out hope that such a system will see the light of day. If and when that happens, what might we want to ask somebody like Scott? It is decidedly difficult for us to put ourselves in his shoes. For one thing, though we might be certain that he is aware, we would like to know what he is aware of. Is he aware of sensations of pain and pleasure? Of the passage of time? Of those near and dear to him? For now, I look forward to working on the science and technology that might one day enable us to uncover the answers.