Primary progressive aphasia and Pick complex.

Ten autopsied patients from a prospectively followed, clinically defined, neuropsychologically and radiologically documented cohort with primary progressive aphasia were histologically characterized. All were variants of frontotemporal degeneration (Pick complex): Pick body dementia, n=3, corticobasals degeneration (CBD), n=4, and tau and synuclein negative ubiquitinated inclusions of the motor neuron disease type, n=3. All shared superficial cortical spongiosis, neuronal loss, and gliosis. Although most patients had fluent anomic aphasia at onset, all progressed to a nonfluent or mute state. Comprehension, episodic memory, and activities of daily living were initially preserved. Three cases with Pick body dementia had verbal apraxia and stuttering at onset. Two of the patients with CBD pathology were older than the average primary progressive aphasia (PPA). All patients developed secondary syndromes either of frontotemporal dementia (FTD) and/or extrapyramidal-apraxic manifestations (CBD). By the time autopsy was obtained, the pathology appeared outside the language areas. Progressive aphasias secondary to Alzheimer's disease (AD) were excluded on the basis of early loss of memory and comprehension.Rather than the previously emphasized histological heterogeneity, clinically probable PPA has a predictive value of a group of related pathologies, collectively named frontotemporal degeneration, or Pick complex. This series of autopsied cases provides evidence for the clinical and pathological overlap of PPA with FTD and CBD, and contributes to the diagnostic and neuropsychological definition of PPA.