Tracking movements that betray the mind

日期:2019-03-01 03:04:04 作者:伯儡鬲 阅读:

By Tom Simonite (Image:W Perry/UCSD) Cameras and motion sensors that track the way people move are giving new insights into mental illness like schizophrenia, bipolar disorder and attention-deficit/hyperactivity disorder (ADHD), say US researchers trialling the technology. Early tests have already uncovered differences in the way patients with these conditions explore an unfamiliar room. Examining the way people move may also shed light on other aspects of the human condition. Psychiatrist William Perry and colleagues at the University of California San Diego, US, were inspired by a technique called behavioural pattern monitoring used on mice. A camera is used to track the animal’s movements as it explores a box with holes along its sides. Studying the pattern of movements has helped researchers understand the effects of drugs, or genetic modifications on brain chemistry. In the human version, the researchers are using two technologies to monitor people exploring a novel environment. “One is the LifeShirt, that contains accelerometers that record motion, and the other is an overhead camera,” explains Perry. In tests, volunteers are told how this technology is used, and that they will also take standard psychological tests. Once they are kitted out in the shirt, “we say ‘can you wait in this room for 15 minutes while we set up the equipment?’,” Perry told New Scientist. While they are in the room, the LifeShirt records their movements onto a built-in recorder, while the overhead camera records their position in the room which contains 10 objects of interest, and a desk, but no chair. Trials so far have involved around 100 people from four roughly equal-sized groups with schizophrenia, bipolar disorder, ADHD, or no mental illness. Analysis of the data is beginning to show links between the way people explore the room and their mental state. For example, people with ADHD move around the room more actively than non-patients. Bipolar patients are even more restless and stay that way – they do not become less active over the 15 minutes, unlike those in other groups. “We’re beginning to notice two subgroups of schizophrenia patients,” adds Perry. “Some explore significantly more than a normal patient would, while others explore much less.” But it is “too early to tell” the exact connections between mental states and movement patterns. Recording data from people over longer periods is a priority, he says. That would make it possible to see if movement patterns are affected by a person’s current symptoms. The team plans to shift the trials into an outpatient clinic, which should make it easier to carry out longer tests. Although some characteristics of the way people move could be judged by eye, the technologies are able to pick up more subtle and complex features, says Perry. “We are building up a kind of physiological grammar, based on the sequence of different actions,” he says. “That’s very useful because it is completely separate from the face-to-face impressions that can make observational study difficult.” Irwin Nazareth studies treatments for mental health problems at University College London, UK. “This is an entirely new area that may throw up interesting results,” he told New Scientist. Doctors sometimes make informal assessments of patients based on the way they move, he says, but the new technology may provide new insights. The observation that movements divide schizophrenic patients into two groups “fits with my own clinical experience”, says Nazareth. “Some patients are very active, while others are under-active.” “Perhaps they could extract the different effects of drugs and the illness on the way people move,” he says, “and if they can identify patterns associated with diseases early enough it might have a role in diagnosis.” Drug companies have expressed an interest in the technique. “They might use it as a way of examining the side effects of a trial drug,” says Perry. “There are endless possibilities for other kinds of studies.” For example, it could be interesting to see if people move differently when stressed, he says. Future studies could exploit other capabilities of the LifeShirt,