臨床症状

Mild behavioral impairment (MBI) and physical frailty are typical syndromes found among older adults and have been attributed to development of cognitive impairment leading to dementia. There is however a paucity of studies observing the association between MBI and frailty in relation to the underlying pathobiology of cognitive impairment including amyloid-beta (Aß) and/or cerebrovascular pathology. This study therefore examined the associations between MBI and frailty among those who were symptomatic at-risk for dementia based on their underlying Aß and/or cerebrovascular pathology in a Southeast Asian cohort.

This cross-sectional study involved 293 community-dwellers exhibiting subjective cognitive decline or mild cognitive impairment with complete neuropsychological, neuroimaging, behavioural and blood biomarker assessments from the Biomarker and Cognition Study Singapore. The 34-item Mild Behavioral Impairment Checklist (MBI-C) and Fried Frailty Phenotype was used to assess MBI and physical frailty respectively. Aß pathology was determined through plasma Aß42/40 ratio ≤0.05, while cerebrovascular pathology was determined through the modified Fazekas rating ≥5. Participants were classified into pure-Aß or mixed (i.e.vascular and vascular- Aß). Independent t-test and logistic regression were administered to observe differences in non-frail and prefrail individuals and determine the association between frailty and MBI separately for the two pathologies.

The study population had a mean age of 63.92±8.27, 60.4% females, 31% were prefrail, MBI-C mean score of 2.59±4.91 and 30% had pure-Aß pathology. Significant differences (p <0.05) in MBI-C total score and domains of mood, impulse and beliefs were observed between those who were non-frail and prefrail in the mixed pathology group, the former having higher mean scores than the latter. No similar differences were observed in the pure-Aß group. Significant associations (p <0.05) were present between increased MBI-C total score (OR:1.11(95%CI:1.02,1.20)) and domains of mood (OR:1.27(95%CI:1.01,1.60)), impulse (OR:1.31(95%CI:1.08, 1.58)) and belief (OR:3.97(95%CI:1.32,11.95)), with likelihood of being prefrail in mixed pathology, upon age, gender and years of education adjustments.

Findings highlight a significant association between MBI and frailty among symptomatic at-risk individuals having mixed vascular-amyloid pathology; worse MBI increasing the likelihood of prefrailty. This association highlights a potential behavioural basis for the detection of and/or intervention for cognitive impairment, warranting further investigation.