Brain, body and mind: understanding consciousness

A bedside device that measures ‘brain signatures’ could help diagnose patients who have consciousness disorders – such as a vegetative state – to work out the best course of treatment and to support family counselling.


The patient might be awake, but to what extent are they aware? Can they hear, see, feel? And if they are aware, does their level of awareness equate to their long-term prognosis?
   - Srivas Chennu

In 10 minutes, Srivas Chennu can work out what’s going on inside your head.

With the help of an electrode-studded hairnet wired up to a box that measures patterns of electrical activity, he can monitor the firing of millions of neurons deep within the brain. A few minutes later, wheeling his trolley-held device away, he has enough information to tell how conscious you really are.

What Chennu is looking for with his electroencephalogram (EEG) is the brain’s electrical ‘signature’. At any one moment in the body’s most complex organ, networks of neurons are firing up and creating ‘brain waves’ of electrical activity that can be detected through the scalp net.

This isn’t new technology – the first animal EEG was published a century ago – but computational neuroscientist Chennu has come up with a way of combining its output with a branch of maths called graph theory to measure the level of a person’s consciousness. What’s more, he’s developing the technology as a bedside device for doctors to diagnose patients suffering from consciousness disorders (such as a vegetative state caused by injury or stroke) to work out the best course of action and to support family counselling.

“Being conscious not only means being awake, but also being able to notice and experience,” he explains. “When someone is conscious, there are patterns of synchronised neural activity arcing across the brain that can be detected using EEG and quantified with our software.”

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Image: Electrical brain 'signatures'. The patient to the left is in a vegetative state; the patient in the middle is also in a vegetative state but their brain appears as conscious as the brain of the healthy individual at the right.
Credit: Srivas Chennu

Reproduced courtesy of the University of Cambridge

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