[Features of cognitive audiory evoked potentials changes at participants of liquidation of chernobyl accident consequences the message II. the analysis of late component P300].

At 10 participants of liquidation of consequences of Chernobyl accident (middle age 50.5 +/- 4.0 years) and at 10 healthy persons (middle age 47.0 +/- 6.0 years) are performed complex neuropsychological examination and registration acoustical cognitive evoked potentials (EP) using odd-ball paradigms. Neuropsyhological research has revealed at liquidators disorders of the higher mental functions, such as aspontanity, decrease speech and a visual memory, and also deficit of higher motor functions. According to the analysis of amplitude-time characteristics of component P300 acoustical cognitive EP a decrease in amplitude of this component at liquidators in all areas of the brain, for both experimental situations for all stimulus in comparison with healthy persons the same age was revealed. At the analysis of latent period (LP) P300 at liquidators the most distinct increase was revealed in a situation of passive listening for all kinds of stimulus. The analysis of reactivity of LP in different experimental situations has shown that at healthy persons during passive listening had similar values for all kinds of stimulus, and an account situation the maximum values--for significant stimulus. For liquidators the type of reaction in the form of increase in LP values at the majority of stimulus in both experimental situations. The analysis of regional LP changes of component P300 has found out the maximum distinctions between groups in frontal area of the left hemisphere. Along with it at liquidators the type the reactions similar for all shown stimulus without dependence from their importance in comparison with norm is revealed "uneconomical, superfluous". It can testify about decreasing of attention and memory reserves and to promote disorder of the higher mental functions. The described of amplitude-time characteristics of component P300 of acoustical EP at liquidators EP can testify to delay of perception, processing and the information analysis in a combination to easing of inhibitory processes leading to the higher mental dysfunctions. The obtained data have similarity to people of old age, supporting a hypothesis about the accelerated ageing of a brain, and also about pathological development of processes of ageing as a result of influence of low doses of radiation.