Objective: To establish the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) neuropsychologic battery as a valid measure of cognitive progression in Alzheimer disease (AD) by deriving annualized CERAD Total Change Scores and corresponding confidence intervals in AD and controls from which to define clinically meaningful change.
Method: Subjects included 383 normal control (NC) and 655 AD subjects with serial data from the CERAD registry database. Annualized CERAD Total Change Scores were derived and Reliable Change Indexes (RCIs) calculated to establish statistically reliable change values. CERAD Change Scores were compared with annualized change scores from the Mini-Mental State Examination (MMSE), Clinical Dementia Rating Scale (CDR) Sum of Boxes, and Blessed Dementia Rating Scale (BDRS).
Results: For the CERAD Total Score, the AD sample showed significantly greater decline than the NC sample over the 4-year interval, with AD subjects declining an average of 22.2 points compared with the NCs' improving an average 2.8 points from baseline to last visit [Group × Time interaction [F(4,1031)=246.08, P<0.001)]. By Visit 3, the majority of AD subjects (65.2%) showed a degree of cognitive decline that fell outside the RCI. CERAD Change Scores significantly correlated (P<0.001) with MMSE (r=−0.66), CDR (r=−0.42), and BDRS (r=−0.38) change scores.
Conclusion: Results support the utility of the CERAD Total Score as a measure of AD progression and provide comparative data for annualized change in CERAD Total Score and other summary measures.