Background: We aimed to test whether in vivo levels of magnetic resonance spectroscopy (MRS) metabolites myo-inositol, N-acetyl-aspartate and choline are abnormal already during preclinical Alzheimer disease, relating these changes to amyloid and/or tau pathology, and functional connectivity. Methods: In this cross-sectional multi-center study (a subset of the prospective Swedish BioFINDER study) we included four groups,