Association of Postural Instability With Asymptomatic Cerebrovascular Damage and Cognitive Decline

Brain MRI in elderly individuals frequently detects asymptomatic cerebral small-vessel disease (cSVD), such as small infarction in the perforator territory (namely lacunar infarction) and periventricular hyperintensity (PVH). Frequency of lacunar infarction and PVH has been reported to increase with age, potentially indicating strong risk of future symptomatic stroke. In addition to these ischemic pathological changes, microbleeds—minor blood leakage through damaged blood vessels detectable via gradient-echo T2*-weighted MRI—are observed relatively frequently in the general population and have also been suggested to be a risk factor for stroke and stroke-related mortality. cSVDs arise from ageand hypertension-related small-vessel damage that shares cerebral amyloid angiopathy as a common cause. In addition to these clinical risk factors and pathogenesis, postural instability in the elderly has also been postulated to be associated with cSVD, particularly with PVH. Reduced physical activity, which includes postural instability as a component, has been suggested to be associated with cSVD in observational analysis and in longitudinal studies. Although the study population in these previous studies numbered <700 individuals, a large-scale longitudinal study (the Cardiovascular Health Study) provided further support for the relationship between physical inactivity and subclinical brain MRI abnormalities in community-dwelling adults aged ≥65 years. However, these studies were based on elderly subjects, with no results available for middle-aged individuals, despite the fact that cSVD can be detected in middle Background and Purpose—Asymptomatic cerebral small-vessel disease (cSVD) in elderly individuals are potent risk factors for stroke. In addition to common clinical risk factors, postural instability has been postulated to be associated with cSVD in older frail patients. Here, we conducted a cross-sectional study to understand the possible link between postural instability and asymptomatic cSVD further, namely periventricular hyperintensity, lacunar infarction, and microbleeds, as well as cognitive function, in a middle-aged to elderly general population (n=1387). Methods—Postural instability was assessed based on one-leg standing time (OLST) and posturography findings. cSVD was evaluated by brain MRI. Mild cognitive impairment was assessed using a computer-based questionnaire, and carotid intima-media thickness as an index of atherosclerosis was measured via ultrasonography. Results—Frequency of short OLST, in particular <20 s, increased linearly with severity of cSVD (lacunar infarction lesion: none, 9.7%; 1, 16.0%; >2, 34.5%; microbleeds lesion: none, 10.1%; 1, 15.3%; >2, 30.0%; periventricular hyperintensity grade: 0, 5.7%; 1, 11.5%; >2, 23.7%). The association of short OLST with lacunar infarction and microbleeds but not periventricular hyperintensity remained significant even after adjustment for possible covariates (lacunar infarction, P=0.009; microbleeds, P=0.003; periventricular hyperintensity, P=0.601). In contrast, no significant association was found between posturographic parameters and cSVD, whereas these parameters were linearly associated with OLST. Short OLST was also significantly associated with reduced cognitive function independent of covariates, including cSVD (P=0.002). Conclusions—Postural instability was found to be associated with early pathological changes in the brain and functional decline, even in apparently healthy subjects. (Stroke. 2015;46:00-00. DOI: 10.1161/STROKEAHA.114.006704.)