Neurophysiological And Psychometric Evaluation Of Cognition In The Normal Aging Population

BackgroundAssessment of cognitive function in normal aging has been considered as an important issue nowadays. There is a generalized proportional decline in mental processing speed among elderly adults that affects all elements of mentation equally.ObjectiveThe aim of this study was to assess cognitive functions in normal elderly individuals using psychometric cognitive assessment scales and electrophysiological studies including late cortical responses, P300 and contingent negative variation (CNV).MethodsThirty-five healthy elderly individuals of both sexes were included. Their ages ranged from 60 to 75 years. The participants were subjected to thorough clinical assessment, cognitive evaluation using psychometric scales and neurophysiological tests in the form of P300 and CNV.ResultsThe results of P300 showed a significant positive correlation between reaction time and age. A significant negative correlation was found between reaction time and performance on the Wechsler Intelligence Scale (WIS) (P = 0.03). The mean amplitude of P300 wave recorded from the parietal region was significantly greater in male participants than in female participants. As regards the results of CNV, a significant negative correlation was noted between N2 latency and the verbal scale of WIS.Comparison of the mean CNV parameters between male and female participants showed that the mean latency of P2 wave was significantly higher in the male population compared with the female population. No significant correlation was revealed between P300 and CNV parameters and scores of Wechsler Memory Scale subtests and parameters of Wisconsin Card Sorting Test.ConclusionResults suggest that the psychiatric scales do not provide a substitute for electrophysiological tests in evaluating the cognitive changes that occur with normal aging. However, there was a limitation for the study in detecting changes because of the narrow age range of the cases.