One of the novel tools was a new diagnostic category, the minimally conscious state.

ECONOMIST: Diagnosing comas

However subsequent tests indicated that she is in a "minimally conscious state" - on the edge of awareness.

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It suggested 18 of those 44 were in a minimally conscious state the same error rate, around 40%, as Dr Andrews had found 13 years earlier in London.

ECONOMIST: Diagnosing comas

The man involved in the study was badly beaten six years ago, leaving him severely brain injured and in a minimally conscious state, in which patients show intermittent signs of awareness.

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Minimally conscious state being a relatively new diagnosis, he says, it may be that some doctors are unfamiliar with its criteria, but that is all the more reason for deferring to the coma recovery scale.

ECONOMIST: Diagnosing comas

This consists of more than 20 clinical tests and is reckoned not only to enable doctors to distinguish patients in a vegetative state from those with minimal consciousness, but also to identify those who were previously in a minimally conscious state but have emerged from it.

ECONOMIST: Diagnosing comas

The law has been clarified and, going forward, in all such cases of patients who are in a minimally conscious state, the High Court does now have the power to decide on whether it is in that patient's best interests for treatment to continue, or whether the patient should be allowed to die naturally, with dignity.

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Insurance companies, for example, prefer a diagnosis of vegetative to one of minimally conscious, Dr Laureys says, because no expensive rehabilitation is required for those in a vegetative state.

ECONOMIST: Diagnosing comas