The Free and Cued Selective Reminding Test Predicts Braak Stage

BACKGROUND: The ultimate validation of a clinical marker for Alzheimer's disease (AD) is its association with AD neuropathology. OBJECTIVE: To identify clinical measures that predict pathology, we evaluated the relationships of the picture version of the Free and Cued Selective Reminding Test (pFCSRT + IR), the Mini-Mental State Exam (MMSE), and the Clinical Dementia Rating scale Sum of Boxes (CDR-SB) to Braak stage. METHODS: 315 cases from the clinicopathologic series at the Knight Alzheimer's Disease Research Center were classified according to Braak stage. Boxplots of each predictor were compared to identify the earliest stage at which decline was observed and ordinal logistic regression was used to predict Braak stage. RESULTS: Looking at the assessment closest to death, free recall scores were lower in individuals at Braak stage III versus Braak stages 0 and I (combined) while MMSE and CDR scores for individuals did not differ from Braak stages 0/I until Braak stage IV. The sum of free recall and total recall scores independently predicted Braak stage and had higher predictive validity than MMSE and CDR-SB in models including all three. CONCLUSION: pFCSRT + IR scores may be more sensitive to early pathological changes than either the CDR-SB or the MMSE.