Functional characteristics of the brain and cognitive functions in patients with autonomic dysfunction combined with clinically apparent asthenia

Twenty six patients with autonomic dysfunction combined with clinically apparent asthenia and 22 healthy control subjects were examined with the use of clinico-neurologic, psychometric, neuropsychological and neurophysiological methods of investigation. Electrophysiologically, compression spectral analysis of EEG and auditory event-related potentials Р300 were used. The patients differed significantly from controls by the reduced attention selectivity, stability and switching, as well as by depression of short-term memory on words and digits. The patients group was also characterized by significantly lower Р300 wave amplitude and spectral power of EEG alpha band in the occipital areas of both hemispheres, in the posterior frontal, the central and the parietal areas of the right hemisphere, as well as by significantly higher spectral power of EEG theta band in the right frontal, the left parietal and the central areas of both hemispheres. One may conclude hat changes of spontaneous and evoked electrical activity of the brain in patients with an asthenia reflect the decrease in general level of brain functional activity owing to abnormal adjusting influences of the limbic-reticular structures. In this case a sufficient flow of cortical activation, necessary for the optimal information processing and maintenance of an adequate level of the directed attention and short-term memory, can not be generated.