Vegetative State

It’s hard to know what to do with people when they are in a vegetative state. By vegetative, I don’t mean that they are spending all day sitting on the couch and eating Oreos. A clinically vegetative state is diagnosed if a patient does not respond to any sort of external stimuli, whether visual, auditory, tactile, or noxious. This can occur after severe brain injury, if a patient wakes up from the fully comatose state but is not actually conscious, a state known as “wakefulness without awareness.”

Okay. So we have a person sitting over here, and they are not responding to anything we do to try to evoke a reaction from them. What do we next?

            Ethically, this is a very complex question. Some people eventually regain their awareness, and recover from this state. Others stay that way forever, in which case it would hardly seem worthwhile to keep them alive. But the question is, how can you know?

            People who are able to react on some levels, perhaps following a command, but not able to fully interact, are described as being in a “minimally conscious state.” This is the key state in clinical assessment. If someone is fully vegetative, they no longer possess the facilities to be able to respond to any stimuli, to be aware. However, if they are minimally conscious, they have the capacity to respond.

            It seems like it should be simple to distinguish between these to states. Poke them with a stick; if they respond, they are conscious. Obviously, there’s more to it than that. It’s difficult to tell if a response is voluntary, even on a subconscious level, or is merely a reflex – a kneejerk reaction. In the past, medical officials have had to rely completely on motor responses, as in a physical action. It’s very possible that a physical response is not actually a sign of awareness, and is merely a reflex, and on the other hand it is very possible that the patient has some bare minimum awareness, but is not able to physically move. Basically, it seems like it is impossible to know – we need some way to actually communicate with these unconscious patients, and, of course, they are not conscious for us to do so.

            With technology continually developing, though, we may not need to. A study a few years ago monitored brain activity of a series of presumed vegetative patients as they were asked to imagine two situations – playing tennis (a motor imagery task) and walking around their house (a spatial imagery task). Theoretically, imagining these two different tasks would activate different parts of the brain, visible in an MRI scan. A small number of the patients did seem to be actually able to imagine these tasks when told, i.e. their brain activity changed when they were told to do a certain thing. This implied that they had some level of awareness – they were at the above-mentioned minimally conscious state, rather than being vegetative.

            Okay. So we’ve figured out whether this person is actually conscious at all. Why do we care? What can we do with that?

            It turns out that this simple information is enough to actually communicate with the unconscious patients. For the next part of the study, the patients who seemed to be able to respond were asked a series of yes and no questions. They were told to answer, substituting the tennis or house imagery for “yes” and “no.” They were able to correctly answer several questions about their personal lives, which had been previously confirmed. This method of communication was considered, with further development, able to allow patients in this state to express their thoughts and opinions and generally improve their quality of life.

            An example of the application of this occurred quite recently. A Canadian patient, Scott Routley had been vegetative and incommunicative since getting into a car crash twelve years ago. Undergoing interrogation in this method, Routley was able to communicate to the doctors that he was not in any pain. It seems like such a simple thing, but the ability to communicate with minimally conscious patients could open many doors in improving their quality of life.

Original report of the study here: http://www.nejm.org/doi/full/10.1056/NEJMoa0905370

- Megan Berry