Neurodegenerative diseases (NDs) are a wide range of neurological disorders affecting distinct subsets of neurons in specific anatomic systems, resulting in variable disease phenotypes [1].Conventional clinicopathological approach allowed to identify several spectra of neurodegeneration, such as those associated to tauopathies, synucleinopathies, and Tar-DNA binding protein (TDP) 43-proteinopathies.However, it has been increasingly appreciated that many NDs overlap at multiple levels, including genetic, molecular, and neuroimaging levels [2-7], thereby overcoming classification approaches based only on clinicopathological patterns [1].In particular, with regard to clinical phenotypes, behavioural and cognitive changes, proven to impact negatively patients' quality of life and prognosis [8,9], have been associated to a large array of NDs, although showing peculiar profiles across the different syndromes.Alzheimer's disease (AD) is usually characterized by a progressive amnestic syndrome in elderly subjects, although younger patients may also present an atypical, focal, clinical syndrome in which a single cognitive domain, not related to memory, is predominantly affected, such as logopenic variant of primary progressive aphasia (lvPPA) and posterior cortical atrophy (PCA)