Altered functional connectivity is associated with Repeatable Battery for the Assessment of Neuropsychological Status across the dementia spectrum

Objective: The quest for non-invasive and cost-effective biomarkers for mild cognitive impairment (MCI) and Alzheimer's disease (AD) has led to growing interest in resting-state functional magnetic resonance imaging (MRI). This study examined associations between whole-brain functional connectivity measures and cognitive performance across a spectrum of cognitive aging. Method: A total of 108 older adults (mean age 74.1 ± 5.7 years), comprised of cognitively intact individuals, participants with amnestic MCI, and those with mild dementia due to probable AD, underwent high-resolution structural MRI and resting-state functional MRI scans and cognitive testing with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Functional connectivity values were derived from a 17-network brain parcellation. Correlations were established between network connectivity values and RBANS Index scores. Results: Analyses revealed that lower RBANS Attention Index and Total Scale scores were significantly associated with increased connectivity between the ventral attention, central executive network, and limbic and default mode networks. Lower RBANS total scores were also associated with functional connectivity strength between the dorsal default mode networks and lateral frontoparietal regions of the central executive network, with increased connectivity observed across the dementia spectrum (Intact-MCI-AD). Conclusions: These findings suggest that aberrant and potentially compensatory increases in functional connectivity may be linked to cognitive decline, supporting the utility of resting-state functional MRI as a promising biomarker for MCI and AD.