Primary progressive aphasia.

Primary progressive aphasia is an important recently emphasized clinical syndrome that is a common early manifestation of Pick's disease and Pick complex pathology. It is defined clinically as slowly progressive language disturbance that remains relatively isolated from other cognitive or behavioral deficits for at least 2 years. Subsequently, it may become associated with behavioral changes similar to those in frontal lobe dementia (FLD), extrapyramidal manifestations, and apraxia similar to corticobasal degeneration (CBD) and with motor neuron disease. Both the common nonfluent or logopenic variety leading to mutism (frontal involvement) and fluent or semantic varieties (temporal involvement) are recognized. Neuroimaging with CT, MRI, and SPECT are useful adjuncts confirming the diagnosis. PPA is a manifestation of frontotemporal degeneration or Pick complex, which is probably the second most common degenerative dementia after AD.