Cognitive/functional measures predict Alzheimer's disease, dependent on hippocampal volume.

OBJECTIVES: This study aimed to investigate the predictive value of cognitive/functional measures in combination with hippocampal volume on the probability of conversion from mild cognitive impairment (MCI) to Alzheimer's disease (AD).

METHODS: The Rey Auditory Verbal Learning Test for immediate memory, Mini Mental State Examination, a functional assessment for independent daily activities and Alzheimer's Disease Assessment Scale were used as cognitive/functional measures and hippocampal volume as neuroimaging measure. Logistic regression and Cox proportional hazard analyses were used to explore the measures' predictive values for AD conversion and time to conversion.

RESULTS: The probability of conversion from MCI to AD was associated with cognitive function, but this was moderated by hippocampal volume: higher at lower hippocampal volume and lower at higher hippocampal volume. General cognitive/functional measures were less predictive than immediate memory in predicting time to conversion to AD at small hippocampal volumes.

CONCLUSION: Effectiveness of cognitive measures and subtle functional abnormality in predicting conversion from MCI to AD is dependent on hippocampal volume, thus combined evaluation should be considered. A combination of hippocampal volume and immediate memory appear to perform best in predicting time to conversion.