Researchers are still far from full understanding of vegetative states.

The bitter wrangle over the fate of an American brain-damaged woman has thrown up both legal and ethical conundrums. But it has also highlighted neurologists’ dearth of knowledge about the brain’s workings after injury.

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The first fMRI maps of cortical activity associated with language processing and tactile stimulation of patients in the minimally conscious state (MCS) are presented. These findings of active cortical networks that serve language functions suggest that some MCS patients may retain widely distributed cortical systems with potential for cognitive and sensory function despite their inability to follow simple instructions or communicate reliably.

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Evidence from persistent vegetative states (PVS)

There are some striking similarities between unconscious states. For example, deep sleep shows slow, high, and regular electrical waves in the brain. But a similar pattern can often be seen in other unconscious states, like some comas, general anesthesia and the momentary loss of consciousness that affects epileptics. In contrast, conscious states like waking and classical REM dreams show fast, irregular, and short waves. These differences are so obvious that many scientists have thought there must be something fundamental about them. Studying unconscious states may be very revealing of the nature of consciousness.

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Is the human brain able to preserve functions, or fragments of functions, in isolated specialised units while the brain at a global level is severely damaged? Furthermore, could one imagine preserved functions in a brain that did not support any mental events?

These are questions that are addressed in a paper entitled “Words without mind” in a recent issue of Journal of Cognitive Neuroscience by Nicholas Schiff and his colleagues at New York Hospital and the New York Medical Centre. Here, they describe a 49-year old woman (LR) who spontaneously utters words that are unrelated to any environmental context, despite the fact that she has been deeply unconscious for 20 years. LR has suffered from three successive hemorrhages – brain damage due to blood flow from ruptured blood vessels – and brain scans with MRI (Magnetic Ressonance Imagery) showed severe damage to a number of brain regions, first of all most of her cerebral cortex of the right hemisphere, and some deeper structures, a.o. her right basal ganglia and thalamus. Only few, isolated islands of LR’s brain were left relatively unharmed after the hemorrhages, some of which were Broca’s and Wernicke’s area in the left hemisphere. They have long been known as the neural basis of the articulation of words and the understanding of words, respectively. But even those areas, though less affected than the rest of the brain, had a metabolism of 66% of the normal value in the case of Wernicke’s area, and only 50% for Broca’s area.

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Imagine that you are anesthesized before a surgical operation. You would probably expect to “black out,” and then wake up some time afterward. What then if you suddenly found yourself conscious of the surgeon’s knife – during the operation? Even worse, you might not be able to let anyone know you are aware.

In 1979 a “medically qualified lady” wrote an editorial called On Being Aware in the British Journal of Anesthesia, describing her own experience of waking up in the middle of a Caesarean section – an incision of her abdomen to facilitate giving birth. “I went unconscious very suddenly,” she wrote, “literally as though someone had switched the lights out. After a gap of uncertain time I gradualy became aware of a mental haze in front of me. I was profoundly confused. This relatively happy state was interrupted by a voice in the space above me (some remark about my bladder) and I instantly understood my predicament: that I was lying there, covered in green towels, my abdomen split open Immediately following this there came three rough stripes across my abdomen. Almost before the third stripe was finished, it was followed by the pain – as suddenly as though I had been stabbed. It was bad from the onset, and it increased in severity. The nearest comparison would be the pain of a tooth drilled without local anesthetic – when the drill hits a nerve. Multiply this pain and then pour a steady stream of molten lead into it. ”

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