Researchers may have found a way to uncover consciousness in coma and vegetative patients just a few days after they have experienced brain injury – and the method seems to help predict who will wake up and recover in months afterwards.
A team of researchers in New York recorded electric activity in the brain of non-responding patients, giving them simple voice commands, such as "holding the right hand opening and closing" or "holding your fingers". %) showed some activity. Out of these 16 patients, eight (50%) continued to follow the commands until they left the hospital. A year later, seven (44%) could work independently of at least eight hours at a time.
By contrast, only 14% of those who did not show electrical activity soon reached recovery levels after one year. The results were published this week in the New England Journal of Medicine.
The study was small, and the authors warned that the results "require validation in larger, multicultural studies that trigger discovery of long term outcomes." in order to help evaluate which patients may come out of the coma or the vegetative state.
The study is not the first to reveal that some patients who do not otherwise react, show brain activity by saying commands that do not turn into behavior, ie, for example, to move their toes. Researchers call it "cognitive-motor dissociation" and meta-analysis of dozens of researches in 2016, which estimated that it was reported in about 14% of patients with chronic disorder. It is close to the prevalence discovered by the New York team.
Electric activity seems to respond to the pronounced command and, perhaps, the brain recognizes and attempts to execute the commandments. But, as New York scientists point out, "is the detected signal recognizing or understanding the command uncertain?" Researchers also remain uncertain whether the detected activity has any effect on the patient's outcomes.
In the new study, this question has been resolved by tracking patients for over a year. All the work was carried out in one intensive care unit with patients received between 2014 and 2017. Patients who did not respond were tested and tested in the first few days at the hospital. The researchers included patients who were in a coma, in a vegetative state, or in a state of "minimal conscious state – minus", in which certain behaviors were maintained at a low level. This involves tracking moving objects with eyes, visual fixing, and responding to pain or discomfort.
The cause of these conditions in the 104 patients involved was different. Some patients had heart failure, while others experienced traumatic brain injury or bleeding.
Open your eyes
The researchers used a common, relatively simple brain activity evaluation test: electroencephalogram. Also known as the EEG, it takes electrical impulses using electrodes attached to the scalp (in this case a standard 21-electrode assembly is used). EEG is often used to diagnose epilepsy, evaluate brain activity after a stroke or during sleep disorder.
The researchers conducted the tests in 25-minute speech command sessions, testing 104 patients who did not react together with 10 healthy people as a control group. Of the patients who did not respond, 16 showed electrical activity, while 88 did not. The following year, six people with EEG activity and 50 without it died, some because they had been removed from life support (four or 24).
However, seven of the original 16 with EEG activities increased and reached the level of recovery that was achieved as 4 or more on the expanded Glasgow scoreboard. It is a clinical scale that scores the outcomes of brain injury from 1 (dead) to 8 ("upper good"), which is generally a continuation of normal life. The score of 4 is considered to be "severe disability". Patients with this result depend on the daily support, but they can be left alone at home for eight or more hours. While 44% (seven patients) with EEG activity after injury reached 4 or more in the year, only 14% (12 out of 88 patients) without EEG had 4 or more. The study was not large enough to associate such outcomes with the causes of brain injury.
NEJM, 2019. DOI: 10.1056 / NEJMoa1812757 (O DOIs).