Beschreibung:
BackgroundThe Alzheimer's Disease Assessment Scale—Cognitive Behavior section (ADAS‐Cog) is the most commonly used cognitive test in AD clinical trials. However, there are concerns about its use in early‐stage disease. Herein we examine those concerns using traditional psychometric methods.MethodsWe analyzed ADAS‐Cog data (n = 675) based on six psychometric properties: data completeness; scaling assumptions; targeting; reliability; validity; and responsiveness.ResultsAt the scale‐level, criteria tested for data completeness, scaling assumptions (item total correlations 0.33–0.59), targeting (no floor/ceiling effects), reliability (Cronbach's α = 0.74), and validity (correlation with MMSE = −0.70) were satisfied. Responsiveness (baseline to 12 months; n = 145) was moderate to high (effect size = −0.73). However, 8 of 11 ADAS‐Cog components had substantial ceiling effects (range 32%–83%), and decreased responsiveness associated with low to moderate effect sizes (0.14–0.65).ConclusionIn our study, many patients with AD found large portions of the ADAS‐Cog too easy. Future research should consider modifying the ADAS‐Cog or developing a new test.