Landmark "vegetative state" paper challenged

Xavier Symons
6 Feb 2013
Reproduced with Permission

US researchers have questioned the results of a landmark study in The Lancet from 2011 on awareness of "vegetative" patients.

That study involved performing EEG scans on 16 patients. The scans apparently showed awareness in three patients when they were given audible commands. The researchers concluded that that some vegetative patients may be aware of their surroundings. This shook neuroscientific assumptions about the "vegetative" state.

However, a subsequent paper in The Lancet has challenged this picture. The authors argue that the 2011 study did not adjust for factors such as muscle activity and random EEG blips. These were wrongly interpreted as responses to commands.

The later study says that these adjustments were left out because of a powerful EEG algorithm. One of the authors, Nicholas Schiff, of Weil Cornell Medical School, explained that "[the algorithm] is a very powerful tool. It will find a pattern for you no problem, but is it a meaningful pattern?... What you're really finding is actually due to chance, but you haven't controlled for chance because it's not so easy to do when you're working with very complex data that have lots and lots of dimensions."

The authors of the original study recognize that if the problems with the algorithm are taken into account, two of the three vegetative state patients no longer showed awareness. But they countered that two of them did respond when scanned with a different method, functional MRI.

Dr Schiff recognized the paramount importance of these tests for patient care. "We see the urgency and need every single day for tests that can be used to help establish awareness and consciousness in brain injured patients."