Imaging
Structural MRI imaging shows a characteristic pattern of atrophy in the temporal lobes (predominantly on the left), with inferior greater than superior involvement and anterior temporal lobe atrophy greater than posterior. This distinguishes it from Alzheimer's disease. Meta-analyses on MRI and FDG-PET studies confirmed these findings by identifying alterations in the inferior temporal poles and amygdalae as the hotspots of disease - brain regions that have been discussed in the context of conceptual knowledge, semantic information processing, and social cognition. Based on these imaging methods, semantic dementia can be regionally dissociated from the other subtypes of frontotemporal lobar degeneration, frontotemporal dementia and progressive nonfluent aphasia.
Read more about this topic: Semantic Dementia