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Appearances Can Be Deceptive
Coma patients also can realise
stimuli from their environment;
One wrong step can have fatal consequences. More than four years ago, Ingrid S. was delivered to the University Hospital of Duesseldorf. She had suffered heavy brain injuries because she fell down the stairs. As a consequence, the 38-year-old woman fell in a coma - a protective body function in order to protect the person from all the pain and fear in a life-threatening situation. But Ingrid S. has never woken up again.
„You can never assume that a coma patient does not realise anything happening around it“, says Simon Eickhoff. He works for the Institute of Neuroscience and Medicine at the Research Centre Juelich. Two years ago he examined Ingrid S. in detail with imaging techniques in order to elucidate the question whether coma patient’s brains still process stimuli.
Ingrid S. is one of about 40,000 people who fall in a coma each year just in Germany. Mostly caused by heavy accidents. In the beginning, most of the unconscious patients are put into intensive care. Later, many will be placed in nursing homes. Often it takes weeks, sometimes even months or years, until coma patients wake up – if this ever happens at all. The patience of doctors, nurses and relatives is put to an acid test and sometimes the motivation to talk to apathetical people disappears.
Senses are also active in coma
However, do coma patients really realise nothing? Eickhoff and colleagues examined the cerebral activity of Ingrid S. First they moved a little sponge over the left or right arm. Functional magnetic resonance imaging revealed that the area of the brain responsible for the sense of touch was activated. After that, they applied light to the patient’s eyes – and observed an activation of the brain area which regulates the visual sense. Interesting but not yet fascinating. However, when the researchers played aloud words to Ingrid S. through headphones, they noticed something amazing: Not only the brain's auditory centre was active, but also the linguistic centre. „This is a hint to the fact that the patient processes language“, says Eickhoff. „We did not expect this!“
This discovery initiated a second study concerned with the question whether Ingrid S. can distinguish persons speaking to her? The researchers observed again promising reactions: words spoken by her children like „hello mum“ or from friends like „hello Ingrid“ activated the brain area responsible for processing emotions. As a comparison: Voices spoken from unknown people "did not activate this certain brain region“ according to Eickhoff.
Heartbeat reacts to relatives
Andreas Zieger has also come to the conclusion that coma patients seem to process emotions. The neurosurgeon has been dealing with the communication from and with coma patients for many years - during a project at the University of Oldenburg by measuring heart frequency and muscle contraction. „Whenever relatives entered the room, the heartbeat got faster and more vividly, just as we expect it in healthy people“, says the professor. „Additionally certain muscles on the forehead, which move if people welcome each other, were also active.“
However, it is not sure, whether these hopeful study results apply to all coma patients because a general evidence does not exist. Nevertheless, the researchers advise physicians, nurses and relatives to deal with coma patients as if they were conscious. According to Zieger, 30 to 45 percent of coma patients can remember experiences when they awake someday. „Once a patient recognised the voice of a nurse who had looked after him during its coma.“