one of the main variants of frontotemporal lobar degeneration
presents specific language disturbances with impaired naming and word comprehension but a fluent and grammatically correct speech. Patients with SD show bilateral
though typically asymmetrical
atrophy of the anterior temporal lobe
and widespread damage of brain functional and anatomical connectivity. Because SD is characterized by a gradual and modality-independent loss of semantic knowledge
it is considered important disease model of the neural mechanism research of semantic memory.