[Evoked potentials in assessing the sensory, activating and cognitive functions of the normal human brain and in cortical and subcortical types of vascular dementia].

Characteristics of the auditory EP under conditions of stimulus recognition (the P300 technique) and parameters of the visual "nonspecific" EP to light flash were studied in healthy subjects of the wide age range (18-78 years old) and patients with vascular dementia of different severity. It was shown that P300 parameters depended on age in healthy patients and on expression of cognitive dysfunction in demented patients. The changes were more pronounced in dementia of the cortical type. The P300 to nonrelevant stimulus was not age-dependent and slightly changed at cognitive dysfunction. Parameters of the nonspecific visual responses (the latency and duration--the index of homeostatic regulation) and maximal amplitude (reflecting the extent of activation processes) were not age-dependent and changed both in subcortical and cortical dementia types (increase in response latency and duration). In cognitive dysfunctions of subcortical origin homeostatic changes in the form of increase in time of homeostatic regulation and deterioration of stabilization of brain electrical processes were more pronounced.