Subtle neurological abnormalities as risk factors for cognitive and functional decline, cerebrovascular events, and mortality in older community-dwelling adults

Background: Subtle, but clinically detectable, neurological abnormalities (SNAs) are associated with impaired physical performance in elderly persons without overt neurological diseases. We investigated whether SNAs were prospectively associated with cognitive and functional status, death, and cerebrovascular events (CVEs) in older community-dwelling individuals. Methods: In participants without history of stroke, parkinsonism and dementia, or cognitive impairment, a score (NSNA) was obtained by summing SNAs detected with a simple neurological examination. Cognitive status and disability were reassessed 4 years later, and deaths and CVEs were documented over 8 years. Results: Of 506 participants free of neurological diseases (mean [SEM] age, 71.9[0.3] years; 42% were men), 59% had an N_SNA of 1 or more (mean [SEM], 1.1[0.06]; range, 0-8). At baseline, the N_SNA increased with age and with declining cognitive and physical performance, depressive symptoms, and disability, after adjusting for several covariates, but did not increase with falls and urinary incontinence. The N_SNA prospectively predicted worsening cognitive status and disability, adjusting for demographics and for baseline comorbidity and cognitive and physical performance. The mortality rates were 22.6, 23.3, 23.9, 58.6, and 91.9 per 1000 person-years in participants with an N_SNA of 0, 1, 2, 3, and 4 or higher, respectively. Compared with an N_SNA of less than 3, having an N_SNA of 3 or higher was associated with an increased adjusted risk of death (hazard ratio, 1.77; 95% confidence interval [CI], 1.25-2.74) and of CVE (hazard ratio, 1.94; 95% CI, 1.07-3.54) over 8 years. Conclusion: In this sample of older communitydwelling persons without overt neurological diseases, multiple SNAs were associated with cognitive and functional decline and independently predicted mortality and CVEs.