Stroke without consequences

Den Tulinov, N+1, based on Frontiers Communications: Brain damage is not always damaging

Here is an inexplicable, at first glance, story (García et al., A Lesion-Proof Brain? Multidimensional Sensorimotor, Cognitive, and Socio-Affective Preservation Despite Extensive Damage in a Stroke Patient // Front. Aging Neurosci., 2017)

A 43-year-old woman, let's call her CG, had a brain hemorrhage. Severe headache, nausea, loss of consciousness, hospitalization. The doctors did a tomogram: typical, i.e. the blood poured out under the membrane between the brain and the skull. The operation was performed, the intracranial pressure was lowered. Ten days later, cardiac arrest, resuscitation, regaining consciousness. In the following days, severe vasospasm, oxygen starvation of the brain, the so-called cerebral ischemia. In short, the brain had a hard time, violations in many places at once. For five days, the woman ignored the left half of the space (visual neglect, when the world exists for a person only on the right; he not only does not see what is on the left, but also does not realize it). Only 41 days in the intensive care unit, then discharged with left-sided paralysis.

Brain damage in a CG patient. Drawing from an article in Frontiers in Aging Neuroscience

Six months later, CG has a convulsive epileptic seizure. After another six months, she is trepanated, fragments of the frontal, temporal and parietal bones of the skull are removed from the right, replaced with a titanium plate. Two months later, she has an ischemic stroke: the amygdala and a number of other brain structures are affected. Again, the clinic, where the woman wakes up, then she is discharged. Without complications.

Everything is normal for the woman – except for a slight loss of sensitivity in the right hand, there are no visible neurological, cognitive, emotional disorders, there are no pathologies in behavior. Neurologists were puzzled. On brain scans, CG has such serious and multiple lesions that she must be disabled. We decided to study it in detail, according to the methodology, suddenly the deviations are not visible to the eye. The woman passed tests for spatial orientation, attention, memory, speech skills, emotion recognition. Scientists assessed her level of anxiety, the ability to build a model of a stranger's consciousness (theory of mind), the ability to purposeful activity (executive functions). Healthy women of a similar age and level of education, without a history of nervous diseases, also passed the same tests.

And what is it? The CG patient was not inferior to them in anything. Although the tests were selected just for the affected areas of the brain. The scientists left the laboratory, went to her home, observed in ordinary life (walks in the morning, cooks, works on the computer, swims every week), talked with relatives. No matter how you look – a normal person, only the skull glitters in the sun.

They write in the article that the case of CG does not fit into accepted theories about the connection between brain anatomy and functions. The authors give explanations and then discard. First, neuroplasticity. The temptation to think so is great, but 43 years already, and only a year has passed since discharge. Very unlikely.

Secondly, the safety margin of the brain, a healthy lifestyle, mental load – all this is a reserve for restoring functions, but it is also unlikely. Too strong and extensive violations.

An extreme option: the second stroke worked as a shake-up and returned the losses from the first. Paradoxes of this type, when repeated trauma restores function, are rare, but they happen. Alas, after the hemorrhage, CG tests did not pass, so here we can only speculate.

Like any anomaly, the CG case has no reliable explanations. After all, they are given within the framework of theory, and that is based on statistics. It is no accident that in the life sciences we are always talking about a sample, the larger it is, the more reliable the conclusion. This is how we accumulate knowledge – knowledge about the average. But the trick of complex systems is that they exhibit some of their properties in rare, special conditions. Without them, you will not understand the system deeply, you will not build a fundamental theory.

Like a curve on a graph, at some values X behaves smoothly, and at others it begins to rush, and you will not know it in any way until you go to the extreme values. You can be deceived for a long time about her equation.

Hence rare and unusual cases, i.e. hidden in the "tails" of statistics, are very important. They should not be discarded, on the contrary, they can become the key, they need to be studied, searched for. The difficulty is that they require special insight of the mind. And not everyone has Luria or Ramachandran. Although in the era of Big Data, such people are even more needed.

Portal "Eternal youth" http://vechnayamolodost.ru  15.02.2017