Comprehensive Clinical and Behavioral Characteristics of Mild Cognitive Impairment According to Amyloid Positivity: A Large Multi-Center Korean Cohort.

Background and purpose: Mild cognitive impairment (MCI) is a transitional stage to dementia, Alzheimer's disease being a major cause. Although amyloid beta-positive (Aβ+) MCI has been well-characterized, Aβ-negative (Aβ-) MCI has not. This study compared the comprehensive clinical and behavioral characteristics of Aβ+ and Aβ- MCI in a large multi-center cohort to better understand the heterogeneity of MCI, and to identify contributing factors to cognitive impairment.

Methods: A total of 686 MCI participants were included. Aβ positivity was determined using Aβ positron emission tomography imaging with a direct conversion Centiloid cutoff value of 25.5. Standardized assessment and questionnaires were used to collect a wide range of clinical information, including vascular risk factors, cognition, daily living function, neuropsychiatric symptoms, and lifestyle behavior. Groups were compared using independent t-tests and χ² tests.

Results: Aβ+ participants (n=406) were older, predominantly female, and more likely to be ApoE4 carriers. In contrast, Aβ- participants (n=280) showed higher vascular risk factors, including diabetes, elevated body mass index, and higher C-reactive protein levels. Aβ+ participants exhibited worse global cognition and functional decline, with a higher prevalence of delusions and appetite disturbances. Meanwhile, Aβ- participants reported greater social engagement, but poorer sleep quality.

Conclusions: This study highlights the distinct clinical and lifestyle profiles of Aβ+ and Aβ- MCI, illuminating the heterogeneity of MCI and its underlying factors in the Korean population.