Independent predictors of cognitive decline in the healthy elderly

We examined if memory, hippocampal volume and gait speed independently predicted cognitive decline in 108 optimally healthy elderly people in a prospective longitudinal observational cohort study (mean follow up 6 years). Milestones included cognitive impairment on the Clinical Dementia Rating Scale (CDR=0.5) or persistent or progressive cognitive impairment. Cox modeling determined if time to onset of cognitive impairment was associated with baseline Logical Memory II score, hippocampal volume, or gait speed independent of age, sex, depression or the Apolipoprotein E4 allele. We found that questionable dementia (QD) occurred in 48 participants in 3.7±2.4 years and persisted (PCI) in 38 of these in 4.4±2.4 years. Logical Memory II performance and hippocampal volume each independently predicted onset of QD. Time to walk 30 feet additionally contributed to the prediction of PCI. Multiple risk factors appear to refine the prediction of QD and PCI, harbingers of dementia, and identify individuals at-risk for cognitive decline.