Abstract
BACKGROUND: Clinical progression of Alzheimer's disease is characterized by impairment in cognition and function. OBJECTIVE: To assess the relationship between cognitive and functional impairment in mild Alzheimer's disease. DESIGN: Spearman's rank correlations between cognitive and functional measures were calculated. Autoregressive cross-lagged panel analyses were used to determine the temporal relationship between cognitive and functional decline. SETTING: Post-hoc analysis of clinical trial data. PARTICIPANTS: Placebo-treated patients with mild Alzheimer's disease from the Phase 3 solanezumab study EXPEDITION 3. INTERVENTION: Placebo. MEASUREMENTS: Cognitive and functional measures were assessed at baseline and at six post-baseline time points through Week 80. RESULTS: Correlation between cognitive and functional measures was 0.41 at baseline and 0.65 at Week 80. Autoregressive cross-lagged panel analysis demonstrated that cognitive impairment preceded and predicted subsequent functional decline, but functional scores did not predict cognitive outcomes. CONCLUSIONS: This study supports the hypothesis that functional impairment predictably follows cognitive decline in mild Alzheimer's disease dementia.