Brain Connectivity Patterns Reveal Distinct Motor vs Cognitive Decline Profiles in Elderly

Differentiating the dominant type of functional decline in older adults—whether primarily motor, cognitive, or both—is critical for designing effective rehabilitation programs. Yet conventional clinical tools often lack the sensitivity to make this distinction reliably, leaving clinicians with a one-size-fits-all approach that may poorly serve complex patients in long-term care.

This cross-sectional study enrolled 60 nursing home residents (mean age 76 ± 11.3 years) from Saint Petersburg, Russia, stratifying participants into three groups: predominantly motor impairment (n=21), predominantly cognitive impairment (n=19), and mixed impairment (n=20). All participants underwent resting-state functional MRI analyzing 164 regions of interest, with statistical correction for multiple comparisons (FDR-corrected p<0.05).

The results revealed strikingly distinct connectivity signatures for each profile. The cognitive group showed heightened intracortical connectivity in language networks and temporoparietal circuits—regions central to memory and higher-order processing. The motor group exhibited robust connections between cortical areas and subcortical motor nuclei as well as the cerebellum, reflecting altered sensorimotor loop function. The mixed group demonstrated the most complex pattern: simultaneous strengthening of frontal-thalamic connections alongside disrupted cerebellar-cortical interactions, suggesting a broader network disintegration.

These findings carry important clinical implications. Identifying biomarkers of functional decline type via neuroimaging could allow therapists and physicians to tailor interventions—targeting motor circuits for one patient and cognitive networks for another—rather than relying solely on behavioral assessments that may blur these distinctions.

Caveats include the small sample size and cross-sectional design, which prevents causal inference or tracking of how connectivity changes over time. The study's Russian-language publication may also limit accessibility, and full methodological details remain unavailable without open access to the complete paper.