“A great deal of experience is required to give a definitive diagnosis of the state of consciousness of a coma patient, particularly since difficult ethical questions are linked to the classification. Innovative technologies such as the brain-computer-interface may now allow better diagnosis in coma patients of whether consciousness is still existent and how pronounced it is, and for the first time also enable communication with those affected,” says Prof. Gustave Moonen (Lüttich, Belgium), speaking at the annual conference of the European Neurological Society (ENS) in Berlin today. More than 3,000 experts from around the world are discussing current research results in all fields of neurology. The correct classification of impaired states of consciousness remains one of the biggest challenges in this field of medicine. “New studies show that around 40% of patients diagnosed as in a persistent vegetative state on closer examination in fact exhibit signs of consciousness”, says Prof. Moonen.
Communication for coma patients with a bio-signal amplifier computer (speech computer) and EEG
New developments in the field of “brain-computer-interface” (BCI) offer important advances here. These are systems which are based on the fact that even the idea of a certain behavior triggers measurable changes in brain activity, which can be converted into signals. Numerous research groups around the world are working on further developing this innovation. An important project funded by the EU goes by the name of “Decoder”.
A current study done by the Coma Science Group under Prof. Steven Laureys, (Lüttich), which is presented today in Berlin, investigates the potential of this concept for the diagnosis of coma patients in a “minimally conscious state” and for communicating with them. The 13 patients, and a control group of healthy volunteers, were required to answer ten to 12 questions using the four commands, ‘yes’, ‘no’, ‘stop’, ‘go’. “We asked the patients a question and the speech computer repeated the four possible answers a number of times. Based on the EEGs, we were able to ascertain whether the patient concentrated on an answer and if so, which,” says Prof. Laureys, explaining the principle. “An important advantage of this method is that we are not dependent on motor responses, which are not even possible for many patients, and which are often just unconscious reflexes.”
The results of this German-Belgian study are very promising: three of the ten coma patients could correctly answer more than half of the questions. Moreover the ten managed an average of 25 to 33% correct answers. Earlier investigations using BCI had already demonstrated very effective communication with patients with locked-in syndrome.
“However there is still a long way to go before the brain-computer-interface becomes part of routine hospital procedure,” says Prof. Laureys. And the development has far-reaching consequences. Experts hope in future with the help of such methods to achieve not only more accurate diagnoses, but also improvements in patient care. “If we can communicate, then we are also in a position to better integrate the needs of the patient in treatment. We can ask them about their pain levels or how they evaluate their quality of life,” says Prof. Moonen. However this will pose new ethical questions, says the expert, especially considering the disparities in Europe in the law and on the use of active or passive euthanasia.
Growing number of coma patients – difficulties in diagnosis hamper correct treatment
According to expert estimates, there are around 230,000 coma patients a year in Europe and around 30,000 are in a persistent vegetative state. The increase in the number of cases is the result of improved prospects in modern accident and intensive care medicine, which has meant a growing number of patients survive traumatic brain injuries, but often with permanent damage.
Advances in diagnostics and communication are important in comatose patients, because the various forms of impaired consciousness are often difficult to distinguish – and the classification has immense consequences for decisions on treatment: coma is defined as a state of deep unconsciousness, from which most patients emerge at the latest in five weeks, or which is followed by brain death. The persistent vegetative state on the other hand is a state in which the patient goes through the “sleep/wake cycle”, but is not conscious. In cases of chronic persistent vegetative state of more than a year, cessation of therapeutic measures such as artificial feeding or hydration is considered justified. The situation is different with the “minimally conscious state”. In this state patients have more than just reflexes and exhibit a distinct low level of consciousness, though they cannot communicate with the outer world. With “locked-in syndrome”, which is the result of severe damage to the brain stem, the consciousness of the patient is fully intact. However they are completely paralyzed and cannot communicate with the outer world – or at best by moving an eyelid.
Caregivers suffer burnout patients’ families suffer anxiety and depression
The care of people in comatose states is a huge pressure on their family members and also on the health professionals involved in their treatment, as is demonstrated by other studies by the Coma Science Group presented at the ENS conference in Berlin. One study investigated 509 doctors and other health professionals involved in the care of coma patients for burnout syndrome. Results showed that 18% of the 509 participants presented a moderate to severe burnout. The majority suffered emotional exhaustion and depersonalization. Caregivers and nurses face a higher risk of burnout than do doctors. “Preventing burnout has to be given higher priority, so that patient care is not endangered,” says Prof. Moonen. Another study shows that family members of coma patients demonstrate a higher incidence of severe anxiety (22%) and depression (16%) than the general population.
Source: European Neurological Society (ENS)