THE eerie eye movements of people in a vegetative state can give an early
warning that they are returning to conscious awareness, British
researchers have
found.
A vegetative state is a mysterious limbo between sleep-like coma and
ordinary
consciousness. People who have suffered a traumatic brain injury can slip
into a
vegetative state for years鈥攐r in some cases, permanently. They have
periods of wakefulness when their eyes are open and move, but they are
unable to
move or speak and are apparently unaware of their surroundings. 鈥淚t doesn鈥檛 look
like anyone鈥檚 in there,鈥� says Sarah Wilson, a psychologist at the University of
Surrey in Guildford, who led the the new research.
Wilson has found a way of picking up early signs of returning awareness in
such people. 鈥淚 think of the vegetative state as a pit or a cave,鈥� she says.
鈥淭hese subtle behaviour patterns appear to be signs that brain-injured people
are at last coming up to the surface, climbing out of the pit.鈥�
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Vegetative state patients who later returned to consciousness showed a
subtle
response to the world around them, Wilson found. They opened their eyes more
often in response to sensory stimulation than patients who did not recover.
Wilson and her colleagues began the research in response to a hunch about a
man who had been in a vegetative state for more than five years. 鈥淲e all had a
funny feeling about this guy,鈥� says Wilson. 鈥淭hough we couldn鈥檛 see him
watching
us, we had this feeling at the back of our necks that we were being
飞补迟肠丑别诲.鈥�
The researchers studied 24 patients in a vegetative state. Every 20 seconds
over two 10-minute periods, they noted whether each patient鈥檚 eyes were open.
This approach revealed that there were distinctive arousal patterns among
people
who eventually emerged from vegetative states.
Among the 12 patients who later regained consciousness, the level of arousal
in the first 10-minute observation period started high, seemingly in
response to
the arrival of the observer, and then declined, Wilson and her colleagues
report
in the latest issue of the journal Brain Injury. The same pattern
occurred after a treatment session involving 20 minutes of 鈥渟ensory
蝉迟颈尘耻濒补迟颈辞苍鈥�
designed to activate the patients鈥� senses of sight, touch, taste and hearing.
None of the 12 patients who remained in a vegetative state during the
three-year
study showed this distinctive arousal profile.
The man who had inspired the research was one of those who recovered. After
three months, 鈥渉e suddenly laughed when I insulted him鈥�, says Wilson.
She stresses that it is far too early to suggest that a lack of the
distinctive arousal pattern could be used to justify discontinuing life support
for someone in a vegetative state. But she says her results stress the need for
further research to improve the diagnosis and treatment of the estimated 1000
people in Britain now in vegetative states.
In some cases, says Wilson, patients are being wrongly diagnosed as being in
a vegetative state when they are actually suffering from lookalike conditions
such as 鈥渓ocked in鈥� syndrome, in which people are aware but unable to move or
speak. These people should be given much more attention than those in a
vegetative state, otherwise they become seriously distressed. 鈥淥nly specialist
units, where everyone dealing with these people on a daily basis is
neurologically experienced, may twig what is happening,鈥� says Wilson.
Wilson鈥檚 research is 鈥渧ery important鈥�, says Roger Wood, clinical director of
the Brain Injury Rehabilitation Trust in Milton Keynes. 鈥淪he is the only person
doing it in Britain, if not the world.鈥�