Focal degenerative dementia syndromes.

Focal degenerative dementia syndromes are associated with a characteristic clinical picture, such as frontotemporal dementia, primary progressive aphasia, semantic dementia, corticobasal degeneration, and the Balint syndrome. A lobar approach may be used to classify the degenerative dementias. The underlying pathology of these various syndromes seems to be less heterogeneous than previously thought.