Postural instability is associated with brain atrophy and cognitive impairment in the elderly: the J-SHIPP study.

BACKGROUND/AIMS: 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.

METHODS

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.

RESULTS

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 x 10(-2) cm(2); p < 0.001). Multiple regression analysis identified COG path length (beta = 0.118; p = 0.032) and one-leg standing time (beta = 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 x 10(-2) cm(2); p = 0.002). AD patients showed a more enlarged THA (78 +/- 55 x 10(-2) cm(2)). 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).

CONCLUSION

Reduced postural stability was an independent marker of brain atrophy and pathological cognitive decline in the elderly.