Differences in P300 parameters, neuropsychological profile, and cognitive impairments in patients with cortical and subcortical dementia

Abstract

In this study we analyzed the parameters of auditory evoked potentials in a stimulus recognition task (the P300 method) and nonspecific visual response to a light flash in 75 healthy subjects of various ages (20–70 years) and 70 subjects (35 males and 35 females, mean age 51 years) with cortical and subcortical cognitive impairments of various degrees (cerebrovascular disorder) with different neuropsychological profiles. It was shown that parameters of the P300 complex depend on both the subject age and his/her cognitive functions and can be used for objective analysis of cognitive impairments. An inverse relationship between the P3 (P300) peak latency and the volume of short-term and operative memory in subjects with cognitive impairments was found. The parameters of the nonspecific visual response (duration and the maximum amplitude), reflecting functioning of the arousal systems of the brain, depended on the type and severity of cognitive impairments but did not depend on the subject's age. Differences in the neuropsychological profiles of cognitive impairments and the pathophysiological mechanisms of their development, reflected by parameters of the evoked potential, as well as differences between the brain structures involved in these process, substantiate the discrimination of two types of cognitive impairments—cortical and subcortical—in subjects with cerebrovascular disorders.