Scientists have found out abnormal changes in the brain function in the cases of Rett syndrome

Scientists from Immanuel Kant Baltic Federal University and Institute of Higher Nervous Activity and Neurophysiology of RAS have described in detail disturbances in rhythm of brain that are observed among patients with Rett syndrome—severe genetical disorder, that leads to decline of mental abilities, memory and ability to control movements. This information will help by diagnosing of disease and estimation of efficiency of drugs. Results of the research are published in magazine Scientific Reports.

Rett syndrome is a genetic disorder of psychoneurogical character, characterized by mutation of gene MECP-2 in X-chromosome. Since boys have only one X-chromosome, such gene mutation leads to death of a newborn. Girls have two X-chromosomes, that is why disease is not fatal and occurs more often. Rett syndrome leads to damage of frontal lobe, and as a result to disturbance of speech, thinking processes, ability to control movements, and also characterized by appearance of convulsions and problems with respiratory system. Up to date this syndrome is incurable, so its carriers find themselves in the state of severe disability. Besides this it is very hard to diagnose it on the early stages, because prenatal development, birth and the first months of life are usually without complications.

Scientists from Immanuel Kant Baltic Federal University (Kaliningrad) and Institute of Higher Nervous Activity and Neurophysiology of RAS (Moscow) using encephalographs have compared activities of brain of 61 child from 3 to 17: healthy ones and suffering from Rett syndrome. With the help of this method authors analyzed rhythms of brain—various frequencies of electric activity, that occur during its work. The research made it clear that during disease increases the power of theta frequency in fronto-central leads that answer for deep concentration and underconsciousness, while power of alpha-diapason, connected with relaxing and meditation lowers.

Besides this, researchers have obtained completely new data: among patients suffering from Rett syndrome there occurs in frontal, central and temporal lobe of brain an increasement of the power of gamma-diapason, that answers for attention, memory, information processing and sleeping. It points to disbalance of neurons' activity and their suppression. Such disbalance can lead to decline of mental capacity, loss of memory and attention.

Scientists for the first time have studied remote time correlations among girls with Rett syndrome, that is cooperation between cells and body tissues, that appear in change of their activity at the long distances and time durations. They showed damage of scale-free characteristics of EEG signal, that don't depend on timescale and are connected with balance of excitation and suppression of activity of neurons of brain. Enhanced coefficient of remote time correlations by patients with Rett syndrome suggest non-optimal condition of neural nets, that have more predictable activity.

"Our results show those pathologic changes in brain work, that go along with disease development. Measured parameters EEG enable to divide groups with an accuracy to 92 %, that points to clinical significancy of presented data. In perspective results can be used as for diagnostics of disease development, and also by elaboration of methods, that control efficiency of various drugs, that can ease patients' suffering",—tells the head of the project, Alexander Hramov, professor of Immanuel Kant Baltic Federal University.

Provided by Immanuel Kant Baltic Federal University