Mild Behavioral Impairment as a Predictor of Functional Status

Objectives: Mild behavioral impairment (MBI) occurs in absence of dementia, but no studies explored whether MBI may limit the individuals' ability to complete everyday tasks necessary to live independently. In this study we elucidated on the relevance of specific behavioral markers on functional decline in both cognitively normal (CN) older adults and with mild cognitive impairment (MCI), and evaluated whether individuals with MBI present worse cognition and neurodegenerative dysfunctions compared to subjects without MBI. Design: Observational cross-sectional study. Setting: Alzheimer's Disease Neuroimaging Initiative (ADNI) database. Participants: Amnesic MCI (aMCI; n = 232) participants and CN (n = 418) individuals. Measurements: Neuropsychological assessment, volumetric MR brain scan, Flortaucipir PET for in vivo assessment of regional tau deposition, functional assessment questionnaire (FAQ), and neuropsychiatric inventory. Results: MBI occurred in 53.5% aMCI and 19.6% CN. In aMCI, the most prevalent behaviors were affective dysregulation (34.4%), impulse dyscontrol (30.6%), and decreased drive/motivation (15.9%), whereas affective dysregulation (13.1%) and impulse dyscontrol (10.2%) were most prevalent in CN. In aMCI, affective dysregulation, decreased drive, social inappropriateness and abnormal perception MBI domains significantly predicted the FAQ score, whereas only decreased drive/motivation MBI domain showed a predicted role on FAQ in CN. No effects of MBI were detected on regional tau deposition or brain volumes in aMCI. Conclusions: Our findings suggest that the occurrence of MBI might predict a high risk of dysfunction in daily life in both aMCI and CN. An early detection of functional impairment may improve the success of disease-modifying interventions.