Examination of cognitive performance and mild behavioral impairment domains of apathy, mood, impulse dyscontrol, social inappropriateness and psychosis in cognitively normal adults aged 50 and over

Abstract

AbstractBackgroundMild Behavioral Impairment describes a spectrum of later‐life onset sustained neuropsychiatric symptoms which are a risk state for dementia. Symptoms which constitute MBI can be grouped into apathy, mood, impulse dyscontrol, social inappropriateness and psychosis. While previous studies have shown the presence of any MBI symptoms (i.e. a global measure) to be associated with worse cognitive performance over one‐year, little is known about the individual constituent domains. In this study we examined the cognitive correlates of each of the five MBI domains over two years in a cognitively normal sample.MethodData from 8,001 participants aged 50 or over taking part in the PROTECT study were analysed. Cognitive performance was assessed at baseline and after two years via completion of a battery of four tests broadly assessing working memory and elements of executive function (paired associates learning, digit span, self‐ordered search and verbal reasoning). MBI status was ascertained at baseline using the MBI‐C at the same time as performance on the first cognitive test. Change in cognitive performance was calculated was a difference score (year 2‐baseline) and analysed in a regression model with MBI domain score as the predictor and controlling for relevant medical and demographics covariates.ResultThe mean age of the sample was 62 and ∼75% were women. Apathy, mood and impulse dyscontrol were associated with worse cognitive performance across all four cognitive tests, the largest effects were observed for impulse dyscontrol on self‐ordered search and verbal reasoning (β= ‐0.05, p=<0.001; β= ‐0.12, p=0.005 respectively). Social inappropriateness was only associated with worse performance on digit span and self‐ordered search (β= ‐0.08, p=0.005; β= ‐0.11, p=0.018) while there were no cognitive changes associated with psychotic symptoms.ConclusionWe present the first longitudinal analysis of the relationship between individual MBI domains and cognition. The worse cognitive performance over two years associated with impulse dyscontrol and social inappropriateness highlight the importance of non‐affective symptomology in later life.