The Checkup: What minimally conscious brains can do
I’d come across a new study suggesting that people in a minimally conscious state can learn a rudimentary form of language, or at least a string of previously unknown syllables.It sounded fascinating, so I called up John Whyte, who has spent much of his career studying disorders of consciousness. Whyte is the perfect person to speak to about this sort of thing, and he has so many mind-blowing insights and anecdotes.
Right at the start of our call, he told me that in many ways, the brains of minimally conscious people behave similarly to those of conscious people, despite their being unable to consistently communicate or be aware of their surroundings. He also told me about some fascinating—and tear-jerking—attempts to pull people in this state back into consciousness. I’ll come back to those in a moment.
This kind of research is really tricky to do in people who are minimally conscious or in an unresponsive wakefulness state, previously known as a vegetative state. Both of these are different from being in a coma. Minimally conscious people show unreliable flickers of awareness and can communicate, but inconsistently. But people in an unresponsive wakefulness state can’t communicate at all.
People in either state experience periods of sleep and waking, while those in a coma show no signs of being awake.
In this study I’d seen, Nai Ding at Zhejiang University in Hangzhou, China, used a cap of electrodes to record the brain activity of people in a minimally conscious state. When his team played audio of familiar words, the participants’ brains showed waves of activity for entire words as well as their individual syllables, suggesting that they recognized each word.
But when the team played new, made-up words, the patterns of activity suggested that they only processed the words as individual syllables.
To “teach” the participants the words, Ding and his colleagues played the new words over and over, thousands of times. By the end of the experiment, the participants showed waves of brain activity for the entire words, just as they did with familiar real words. This suggests that they’d learned the new words.