Postural Instability Is Associated with Brain Atrophy and Cognitive Impairment in the Elderly: The J-SHIPP Study

<i>Background/Aims:</i> Mobility impairment in older adults has been suggested to be a marker of subclinical structural and functional brain abnormalities. We investigated a possible association between static postural instability and brain abnormalities and cognitive decline. <i>Methods:</i> The study subjects were 390 community residents without definitive dementia (67 ± 7 years old) and 21 patients with Alzheimer’s disease (AD). Brain atrophy was measured by MRI. <i>Results:</i> The mobility of the posturography-measured center of gravity (COG) was positively associated with the temporal horn area (THA; r = 0.260; p < 0.001). Subjects who could not stand on one leg for >40 s (n = 102) showed a significantly larger THA (22 ± 18 vs. 14 ± 11 × 10^–2 cm²; p < 0.001). Multiple regression analysis identified COG path length (β = 0.118; p = 0.032) and one-leg standing time (β = 0.176; p = 0.001) as independent determinants of THA. Mild cognitive impairment (MCI) subjects (n = 61) had a significantly enlarged THA compared to that of normal cognitive subjects (22 ± 16 vs. 16 ± 13 × 10^–2 cm²; p = 0.002). AD patients showed a more enlarged THA (78 ± 55 × 10^–2 cm²). Subjects with cognitive decline showed a significantly shorter one-leg standing time (normal: 50 ± 17 s; MCI: 42 ± 21 s; AD: 18 ± 20s; p < 0.001). <i>Conclusion:</i> Reduced postural stability was an independent marker of brain atrophy and pathological cognitive decline in the elderly.