Discover - USA (2020-01 & 2020-02)

JANUARY/FEBRUARY 2020. DISCOVER 81

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There are some things that life

never prepares you for — like the

phone call that a loved one is

in a coma, and you’re responsible for

making their end-of-life decisions if

they don’t wake up. These decisions

are further complicated by the

fact that there’s no true test for

consciousness, and it’s difficult for

doctors to predict who will emerge

from a coma and who won’t.

But in June, a team of researchers

at the Columbia University Irving

Medical Center said they’d found an

effective tool for spotting signs of

“hidden consciousness” in comatose

patients. And it’s already readily

available in nearly all hospitals around

the world: electroencephalogram (EEG)

machines that detect electrical activity in the

brain.

The study, published in the New England

Journal of Medicine, found that subtle

patterns in brain activity could signal that

a person is aware, but physically unable to

show it. The researchers discovered hints of

hidden consciousness in 1 in 7 people just

days after sustaining a serious brain injury.

A year later, the people who initially showed

signs of hidden consciousness were more

likely to have recovered.

The EEG work came after a similar study

on hidden consciousness from earlier in the

year. In February, a different research team

found that functional MRI (fMRI), which

detects brain activity based on blood flow,

could also spot brain patterns that signal

consciousness. However, use of fMRI comes

with a high cost, and it’s challenging to

perform these tests on someone with a brain

injury and who might not be clinically stable.

Patients would have to leave the safety of

the intensive care unit, and potentially the

hospital altogether, to be transported to an

MRI machine.

This logistical challenge is particularly

unfortunate because conscious states can

fluctuate in a patient, says Jan Claassen,

head of neurocritical care at Irving Medical

Center, who led the new study.

“That is a disadvantage,” says Claassen.

“[With fMRI], you have just a snapshot in

time, whereas with EEG you can do it at the

bedside — you can potentially repeat it again.”

When someone is unresponsive for

days or weeks, doctors use a variety of

tests to determine the likelihood of the

person pulling through. But predictions

tend to be inaccurate, which makes these

new results encouraging. Of course, the

researchers say more work is needed to

better understand how EEG can be used to

predict recovery across a range of different

types of brain injury.

EEGs Eke Out

Buried Brain

Activity

BY MEGAN SCHMIDT

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It’s hard to know what’s happening in the mind of a

comatose patient. But new research suggests EEGs

(above) can reveal hidden consciousness, more

easily, cheaply and effectively than MRIs (below).

Arctic Canada’s Grassy Bay
Formation (top) is home to the
earliest fungi in the fossil record.
More than 900 million years old,
the microfossils are about a tenth
of a millimeter long and consist of
branching filaments attached to
bulbous structures (above).