Scientists Read Minds Of Coma Patients With Brain-Computer Interface
Coma patients are very challenging, both medically and ethically. Diagnosing the level of a comatose person's brain activity in response to questions has been interpreted mainly by the level of physical response (the lifting of a finger, the blink of an eye, etc.) from the patient. But the European Neurological Society is meeting in Berlin today and neurologists are reporting new developments in the field of brain-computer interface (BCI).
"Persistent vegetative state" (PVS) is a term used to describe persons who are in wakeful comas for longer than a few weeks - awake, but non-responsive to external stimuli. Belgian Professor Gustave Moonen, speaking about the ability of BCI to better diagnose this state, said that about 40 percent of patients diagnosed with PVS show some signs of consciousness using BCI.
BCI is powerful enough to show the slightest brain activity in response to even an idea presented to a comatose patient. Another study presented by German Professor Steven Laureys, investigated how BCI could be used to identify those patients who are "minimally conscious," a condition that may be present in those that are completely paralyzed and can't communicate physically, but whose consciousness is in tact.
This experiment used a control group of 13 healthy volunteers and 10 coma patients and posed 12 questions to each group. The possible responses included four commands: yes, no, stop, go. A speech computer was used to teach the possible answers to the questions. Based on the EEGs of the coma patients, the researchers were able to determine which patients were thinking about an answer and which answer they were thinking.
"An important advantage of this method is that we are not dependent on motor responses, which are not even possible for many patients, and which are often just unconscious reflexes," reported Professor Laureys.
Three of the 10 coma patients could answer the questions correctly more than 50 percent of the time; each question was answered correctly by all patients from 25 percent to 33 percent of the time.
Professor Laureys said it would be a long time before BCI becomes routine procedure in hospitals. The use of BCI will result in more accurate care for coma patients and for those whose responses can be read through BCI, medical personnel will be able to ask questions about the patient's perceptions and needs.