Mild Behavioral Impairment and Cortical Thinning: Biomarkers of Early Neurodegeneration
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Background
Mild Behavioral Impairment(MBI) is increasingly recognized as an early phenotypic marker of neurodegeneration, with neuropsychiatric symptoms(NPS) frequently emerging prior to cognitive deficits. While structural neuroimaging studies suggest a link between cortical thinning and NPS, the link between MBI and cortical morphology remains underexplored in diverse community-based cohorts. This study investigated whether early behavioral alterations, assessed via the Mild Behavioral Impairment Checklist(MBI-C), correlate with region-specific cortical thinning in a Southeast Asian cohort.
Methods
We conducted a cross-sectional analysis of 969 participants (mean age 61.99±10.19years;39.6% male;87.2%Chinese) enrolled in the Biomarkers and Cognition Study in Singapore(BIOCIS), ranging from cognitively normal, subjective cognitive decline(SCD), to mild cognitive impairment(MCI). MBI was quantified using the self-reported MBI-C. T1-weighted MRI scans were processed with FreeSurfer to measure cortical thickness. Associations between MBI-C scores(total/subdomains) and cortical thinning were examined.
Results
Higher MBI-C Belief scores were significantly associated with cortical thinning in the right hemisphere(β=−0.0177;95%CI:−0.0342to−0.0012;P=0.035). Region-specific analyses showed significant thinning in posterior banks of the superior temporal sulcus, fusiform gyrus, superior temporal gyrus, temporal pole, and transverse temporal gyrus, which remained significant after false discovery rate correction(FDR P=0.042–0.045). Additional thinning was noted in right postcentral and supramarginal gyri and right insula(FDR P≤0.039).
Conclusions
Elevated MBI, particularly abnormal beliefs, is linked to cortical thinning in regions subserving memory, sensory integration, and emotional regulation, especially within the right hemisphere. These findings highlight the potential of MBI-C as an early neurodegenerative marker and underscore the need for longitudinal studies to clarify temporal dynamics and mechanisms underlying behavioral symptoms and neurodegenerative processes.
