People In Vegetative States Are “Listening”

Halloween is over, but this frightening story we're about to tell is actually real. For many, it's one of our worst nightmares: being paralyzed, unable to move, speak, or see, but still able to hear those around us. And, research published yesterday in the journal Neuroimage: Clinical might have found just that.

In an experiment using non-invasive Electroencephalography (EEG), researchers hooked up both healthy volunteers and people in minimally-conscious and vegetative states in order to measure their brain response to certain directives and stimuli.

The participants heard a series of different words, one per second, and were asked "to alternatingly attend to either the word ‘yes’ or the word ‘no,’ each of which appeared 15% of the time." This tested the ability of participants to separate out the "important" words from the "filler" words that were repeated intermittently. To put it another way, they were testing the participants' ability to pay attention.

Amazingly, one of the individuals in a vegetative state was able to filter out the irrelevant words and hone in on the relevant ones — just like a healthy person. Then, using brain-imaging techniques, they also found this person was able to follow simple verbal commands — like imagining himself playing tennis. We'll just let that one sink in.

While this evidence is only preliminary — and there were many vegetative individuals in the study who did not respond to verbal cues — it's incredible that we have the ability to observe the thought processes in supposedly vegetative individuals. There are already technologies emerging for conscious, paralyzed individuals that allow them to use only their brains to interface with computers. It's theoretically possible that this sort of technology could be extended to even those who appear vegetative, allowing them to interact with the outside world again.