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The aim of the research was to reveal features of distribution of DC-potential level of the brain in patients with chronic mercury intoxication.Materials and methods. The study involved 33 male patients with chronic mercury intoxication and 38 healthy men (comparison group) who, by the specifics of their professional activities, were not exposed to neurotropic substances. We used the electrophysiological method of neuroenergy mapping.Results. In the group of patients with chronic mercury intoxication, persons with a low level of constant potential prevailed when compared with the comparison group (36 and 11%, respectively). With a decrease in the level of constant potential in the frontal parts, an increase was observed in the central leads (Fpz – Cz = –1,2 (–6,3–12,6) mV), and with an increase in it, a decrease in the occipital (Fpz-Oz = 4,2 (–4,8–21,4) mV) and the right temporal (Fpz-Td = 0,01 (–6,5–16,3) mV) areas.Right hemisphere temporal asymmetry was manifested in an increase in the Td-Ts index (p = 0,03) when compared with that of the comparison group, (0,66 ± 0,01) and (–4,34 ± 1,12) mV, respectively. Using discriminant analysis, five reliable diagnostic signs were identified: the values of the parameters of the parietal (Pz), right parietal (Pd), right temporal (Td), central (Cz), occipital (Oz) leads. The most informative sign was the value of the index of the parietal lead (Pz, F = 21,1).Conclusion. A distinctive neurophysiological sign associated with chronic exposure to metallic mercury vapors is an increase in indices of the parietal, right parietal, right temporal, central, occipital leads compared with those inherent in the normal population.

Biofeedback in toxic encephalopathy in the late period chronic intoxication by mercury and complex toxic substances led to decrease in the EEG changes, performance improvement of the amplitude and latency evoked potentials, in vibration disease – to decrease manifestations of angiodystonia syndrome, recovery of neuromuscular conductivity. The effectiveness of biofeedback is confirmed by changes in subjective measures of the patients.

The neurophysiological (the registration of induced potentials P300) and the psychological examinations of 70 patients, males, with chronic mercury intoxications (ChMI) and discirculatory encephalopathy (DE) have been performed with aim to reveal the features of cognitive disorders (CD). The study results have shown the presence of light CD and small demention in the patients of both groups, preferably, of subcork type for the patients with ChMI and preferably of cork type – for the patients with DE.