Mild behavioral impairment: Prevalence, clinical profile, and prognosis in a memory clinic cohort in Singapore

Abstract

AbstractBackgroundMild behavioral impairment (MBI) is characterized as later‐life emergent and persistent neuropsychiatric symptoms (NPS) that are suggestive of early manifestations of Alzheimer’s Disease (AD) and dementia. This study aims to investigate the prevalence, clinical correlates, cognitive trajectories, and dementia risk of MBI in a clinical cohort.MethodIn a Singaporean longitudinal cohort, 309 dementia‐free participants (mean age=71.6 [SD=7.8], 52% females) underwent annual neuropsychological, neuropsychiatric, and clinical assessments for up to four years. The diagnosis of MBI was ascertained using neuropsychiatric inventory assessments at two time‐points. Global and domain‐specific cognitive Z‐scores were calculated from a comprehensive neuropsychological battery, and Clinical Dementia Rating sum‐of‐boxes (CDR‐SoB) scores were used to assess disease progression.ResultA total of 72 (23.3%) participants had MBI. Cross‐sectionally, MBI patients performed poorer in global cognition (β=‐0.27 [‐0.51–0.03], p=0.026), particularly in memory (β=‐0.56 [‐0.79–0.33], p<0.001), executive function (β=‐0.33 [‐0.62–0.03], p=0.030), and visuomotor speed (β=‐0.20 [‐0.39–0.02], p=0.031) domains. On follow‐up, MBI patients showed faster decline in global cognition (β=‐0.19 [‐0.27–0.11], p<0.001) (Fig. 1) and faster increment in CDR‐SoB (β=0.96 [0.74‐1.19], p<0.001) (Fig. 2) as compared to non‐MBI elderly, regardless of cognitive status. On follow‐up, 40.3% (n=29) of MBI patients progressed to dementia, compared with 8% (n=19) of non‐MBI elderly. MBI diagnosis was associated with a significantly higher risk of dementia (Hazard Ratio=6.28 [3.51‐11.23], p<0.001) (Fig. 3).ConclusionMBI may be an early neurobehavioral marker of cognitive decline leading to dementia. Incorporating MBI evaluations into clinical assessments may identify high risk patients for dementia who may benefit from intervention.