Researchers have found that many patients with brain damage, who appear unconscious, do still think and understand some things being said to them. — dpa
Little is known about the brain and states of consciousness, but recent studies may give grounds for hope.
If a person suffers a severe brain injury, then lands in intensive care in a coma, doctors and relatives will ask whether the patient has regained consciousness yet.
They often ask the injured person to move their hand, for example, and if the patient fails to do so, they often assume the patient is still in such a deep coma that they are not aware of anything.
But this may not necessarily be true, studies show.
Research centre studies have shown that some 15% to 20% of patients are thinking cognitively even if they make no outward response when addressed.
But the latest study, published in the New England Journal of Medicine, found that this actually applies to around 25% of patients.
Following instructions
“Some patients with severe brain injuries do not appear to process their outside world,” says first author Dr Yelena Bodien from the Centre for Neurotechnology and Neurorehabilitation at Massachusetts General Hospital in the United States.
“However, when they are examined using advanced techniques such as functional magnetic resonance imaging (fMRI) and electroencephalography (EEG), we can detect brain activity that suggests otherwise.”
The scientists examined patients with severe brain injuries from the US and Europe who were involved in road accidents with traumatic brain injury, who had a stroke, or who were resuscitated after cardiac arrest, often months before.
While their brains were scanned in tests, they were given instructions, such as “imagine opening and closing your hand”.
Or they were asked to imagine they were performing a sport.
Of the 241 patients studied who were lying in bed and showed no externally visible reaction, tests showed that 60 of them still followed the instructions internally for several minutes.
That means that the group was attentive, understood language and had a short-term memory, the authors say.
Would treatment help?The international study, conducted over a period of several years, is very important, says German Society of Neurology (DGN) Neurological Intensive Care Medicine Commission spokesman Professor Dr Julian Bösel.
This is as it includes the largest patient group to date, was carried out at six medical centres, and has recorded the phenomenon more systematically than usual.
But it raises a central ethical question: namely, whether or not therapy should be continued, he says.
Severe brain injuries often cause an impairment of consciousness.
A coma is a state of complete unconsciousness, where patients do not open their eyes, even in response to pain stimuli.
There are other degrees and levels of partial consciousness, such as a minimally conscious state, or when patients occasionally open their eyes and have distinct sleep-wake phases, even if they are unresponsive.
Such disorders of consciousness can last for days, weeks, months, or even years.
“In certain constellations, studies such as the present one could provide an opportunity to examine more of these patients with EEG and observe them over a longer period of time,” says Prof Bösel.
We can deduce from this that, when in doubt, certain patients should be given more time, he says.
However, it is unclear whether special therapies help such people.
For some time now, attempts have been made to achieve something with behavioural therapies, medication or other procedures, but mostly without resounding or lasting success.
A Massachusetts General Hospital team is also using modern technology to probe these questions, testing brain-computer interfaces to connect the brains of patients with computers so that they can communicate with each other.
But the latest study doesn’t tell us anything wholly new, in the view of German Brain Foundation president Prof Dr Frank Erbguth.
“It is clear that the phenomenon exists,” he says.
However, just because electrical patterns or active regions in the brain are measured does not mean that these people really have a higher form of consciousness, he says, adding the fMRI or EEG of anaesthetised people shows similar levels of consciousness.
Treat them as aware
So how high is the rate of people who show cognitive abilities but lack behavioural signs?
The study authors and the German scientists agree it is difficult to make definitive statements on this.
In the new study, the tests were not standardised and the patients were selected.
“Also, the causes of brain damage that were summarised here were completely different,” says Prof Erbguth.
But the percentage figures from studies like this one show that as Prof Bösel says: “We should be aware that perhaps even more patients with impaired consciousness are aware of what is going on around them than we thought.”
It is still common in many places for comatose patients to be spoken to at the bedside as if they were not there, he says.
“But many carers do a really good job, greeting the patient, introducing themselves and telling them what they are doing with them.”
That is an approach that everyone should take this to heart, including doctors on ward rounds and visitors, he says.
Do not address frightening or upsetting topics while beside the patient.
“We stand at the bedside and don’t know that much about what’s really going on in the patient’s head.”
Prof Erbguth agrees, saying: “People in intensive care units and rehabilitation wards should always be treated as if they are aware of something.
“You talk to them and treat them with respect, as they already are today.” – By Doreen Garud/dpa
