MAPT and Parkinson disease: Aβ species and total tau have been associated with ventricular enlargement, but not with hippocampus volume.33 Associations between lower Aβ42 and higher tau and frontal, parietal and temporal cortical atrophy were found in PD with dementia,34 and lower Aβ42 in non-demented PD patients was prospectively associated with parietal and occipital thinning.26 An association between low t-α-syn and frontal cortical thinning in PD without dementia has also been reported.31 To our knowledge, no other study has evaluated the hippocampal subfields in relation to CSF biomarkers in PD.