- Individuals in a comatose state may be more aware than initially believed.
Following a serious head trauma, an individual might end up in a coma on an intensive care unit. Family members and healthcare professionals often ponder if the patient has regained consciousness. To ascertain this, they may prompt the patient to perform actions like moving a hand. If there's no response, some conclude that the patient is still in such a deep coma that they're oblivious to their surroundings.
However, research suggests that this assumption might not always be correct. There are instances of individuals who exhibit no external signs of being addressed, yet their brains display cognitive activity. Early studies at individual research facilities discovered this activity in approximately 15 to 20 percent of the subjects examined. A recent study published in the esteemed journal "New England Journal of Medicine" reveals a higher rate of around 25 percent.
Yelena Bodien, the lead author from the Center for Neurotechnology and Neurorehabilitation at Massachusetts General Hospital, explains: "Some patients with severe brain injuries seem unresponsive to their surroundings. However, when we examine them using advanced techniques such as functional magnetic resonance imaging (fMRI) and electroencephalography (EEG), we can detect brain activities that hint at something different."
Severe brain injuries due to accidents, strokes, heart attacks
In this study, experts examined patients with serious brain injuries in the USA and Europe. These patients had suffered from traumatic brain injuries due to accidents, strokes, or survived cardiac arrests commonly months before. During the tests, their brains were scanned while they were given instructions, such as, "Visualize opening and closing your hand." Or they were asked to imagine playing a sport.
Out of 241 participants, who appeared to exhibit no external reaction, 60 still followed the instructions internally for several minutes. These individuals were thus attentive, understood language, and displayed short-term memory, according to the authors.
Should additional treatments be administered?
This interdisciplinary study conducted over several years is significant, says Julian Bösel, spokesperson for the Commission on Neurological Intensive Care Medicine of the German Society for Neurology (DGN). The extensive patient group, the involvement of six medical centers, and the more systematic observation of the phenomenon make this study unique. The research addresses several ethical questions, including whether to continue treatment.
Severe brain injuries frequently lead to loss of consciousness. A coma is a state of complete unconsciousness without any response to pain. If a person occasionally opens their eyes, displays distinguishable sleep-wake phases, but shows no signs of responsiveness, the term "vegetative state" (VS) or "unresponsive wakefulness syndrome" (UWS) is used. This term is used to describe a state with retained minimal consciousness, if eye movements occur or if simple commands are followed.
Disturbances of consciousness can persist for days, weeks, months, or even years. "Studies like this one could, in certain circumstances, provide reasons to examine additional patients through EEG and observe them over longer periods," says Bösel. This might indicate that selected patients should be given more time in cases of doubt.
However, it's unclear if special therapies would help these individuals. Efforts have been made to affect improvement using behavioral therapies, medication, or other methods, but with limited or no lasting success. A team at Massachusetts General Hospital is also implementing modern technology using brain-computer interfaces to establish a connection between the brains of such patients and computers, allowing them to communicate.
Frank Erbguth, President of the German Brain Foundation, finds that the new study doesn't present new insights. "That the phenomenon exists is clear," he says. Nevertheless, electrical patterns or active regions in the brain do not definitively indicate a higher level of consciousness. Such activity can also be found in the fMRI or EEG of anesthetized patients.
Both experts concur on how to address patients who do not respond. "Patients in intensive care and rehabilitation centers should always be treated with the assumption that they are aware of their surroundings," says Erbguth. "This means speaking with them and treating them respectfully, which is already the case today."
Uncertain number of affected individuals
Therefore, what is the incidence of individuals who exhibit cognitive abilities but lack behavioral indications? Both the study authors and German experts concur that making definitive statements is challenging. The tests in the new study were not standardized, and the patients were selected. "Moreover, the study combined various causes of brain damage," says Erbguth.
However, emphasizes Bösel, the percentage figures from studies like this demonstrate that: "We should be aware that perhaps more consciousness-disordered patients than we think are aware of their surroundings." In his experience, it is commonly practiced in many places to speak at the bedside of comatose patients as if they are not there. "Many nursing staff do this very effectively by greeting the patient, introducing themselves, and explaining what they are doing to them."
Everyone should keep this in mind, including doctors during their rounds or visiting relatives, and avoid discussing distressing topics at the bedside. "We stand at the bedside and don't know what's truly happening in the patient's mind, and we must admit that quite honestly."
Despite showing no external signs of response, some patients with severe brain injuries still process instructions internally as revealed in the study. These individuals exhibit cognitive activity, such as visualizing hand movements or imagining playing a sport, indicating attention, language comprehension, and short-term memory.
Furthermore, advanced techniques like functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) can detect brain activities in patients with severe injuries, suggesting a level of consciousness beyond their apparent unresponsiveness.
