Markers of Alzheimer's disease in a population attending a memory clinic

Background: New marker-based criteria for the diagnosis of Alzheimer's disease (AD) were recently proposed. We describe their operational translation in 144 consecutive patients referred to our Memory Clinic. Methods: Visual ratings of hippocampal atrophy and of cortical glucose hypometabolism in magnetic resonance imaging and positron emission tomography, and concentrations of total tau and Aβ1-42 in cerebrospinal fluid were assessed in 12 patients with subjective memory complaints (SMCs) (Mini-Mental State Examination [MMSE] score, 28.0 ± 1.1 [mean ± SD]), 37 with mild cognitive impairment (MCI) (MMSE, 25.1 ± 3.6), 55 with AD (MMSE, 21.1 ± 3.5), and 40 with non-AD dementia (MMSE, 21.6 ± 5.5). Results: The sensitivity for AD of each individual biomarker was higher (65% to 87%) than for MCI (18% to 50%). Each biomarker's specificity for SMC and non-AD dementias was good to moderate (83% and 53%). Positivity for at least one marker increased the probability 38 times of belonging to the AD group (P <0.0001). Conclusion: The new diagnostic criteria can be operationalized in clinical routines, but longitudinal studies of MCI patients will need to assess the criteria's prognostic value.