24 Chapter 2 or other neurological or psychiatric conditions (e.g. major depression, schizophrenia) were not met (10, 23). Follow-up diagnoses were available for 342 participants (3±2 years). These participants were on average three years older, but otherwise comparable to the entire sample of 693 participants. At follow-up, diagnoses were re-evaluated as SCD, MCI, AD dementia, or other types of dementia (frontal temporal dementia (FTD), primary progressive aphasia (PPA), vascular dementia, Dementia with Lewy bodies (DLB)) (24-27). The clinical endpoints were (i) progression to dementia, and (ii) progression to MCI or dementia. Participants were included for the current project when MRI and CSF were available within one year of the diagnosis. Standard Protocol Approvals, Registrations, and Patient Consents The research is in accordance with the ethical consent by the VU University and with the Helsinki Declaration of 1975. For all patients written informed consent was available. Neuropsychological assessment All participants received an extensive standardized neuropsychological assessment (18). We used the Mini Mental State Examination (MMSE) for global cognition. To asses memory we used the Visual Association Test version A (VAT-A) and total immediate and delayed recall of the Dutch version of the Rey auditory verbal learning task (RAVLT). For language we used category fluency (animals). To assess attention, we used the Trail Making Test A (TMT-A), the forward condition of the Digit Span and Stroop task I and II (naming and color naming). To assess executive functioning we used the TMT-B, Digit Span (backwards) and Stroop task III (color-word). Raw test scores for TMT and Stroop were log transformed, because the data were right-skewed, and subsequently inverted, such that a lower score implies worse performance. The proportion of missing tests ranged from 7.6% for the TMT-A to 19.1% for the Stroop III. In total, 1424 neuropsychological investigations of 693 patients were available (299 ≥2; range 2-12, median 3). MRI All participants underwent an MRI-scan of the brain (Siemens Avanto, n=7; GE Discovery MR750, n=14; Impax, n=119; 3T Philips Ingenuity TF PET/MR system, n=123; 1.5T GE Signa HDxt, n=21; 3.0T GE Signa HDxt, n=262; 1.5T Siemens Sonata, n=27; 3T Toshiba Vantage Titan, n=119; Vision, n=1). The protocol included 3D T1-weighted images, 3D T2-weighted images and 3D T2-weighted fluid-attenuated inversionrecovery (FLAIR) images (18). Visual rating of medial temporal lobe atrophy (MTA)