Primary progressive aphasia and kindred disorders.

The existence of progressive aphasias has been known for more than 100 years. Pick (1892, 1904), Sérieux (1893), Franceschi (1908), and Rosenfeld (1909) were among the first to report such patients. The current resurgence of interest in this condition can be traced to a 1982 report of six patients with a slowly progressive aphasia and to the subsequent delineation of the primary progressive aphasia (PPA) syndrome (Mesulam, 1982, 1987, 2007; Mesulam and Weintraub, 1992). According to currently accepted criteria, the PPA diagnosis is made in any patient in whom a language impairment (aphasia), caused by a neurodegenerative disease (progressive), constitutes the most salient aspect of the initial clinical picture (primary). The term language in this definition is used in its technical neurological sense to refer to all component processes served by the left hemisphere language network, including phonology, morphology, syntax, semantics, naming, wordfinding, reading and spelling. The language impairment in PPA can be fluent or non-fluent and may or may not interfere with word comprehension. Memory for recent events is preserved although memory scores obtained in verbally mediated tests may be abnormal. The recognition of familiar facts and objects is preserved (Adlam et al., 2006). Minor changes in personality and behavior may be present but are not the leading factors that bring the patient to medical attention or that disrupt daily living activities. This selective clinical pattern is most conspicuous in the initial stages of the disease, covering an interval of approximately 2 years after symptom onset. Hundreds of PPA cases have been reported and a sizable research literature on this topic has appeared (Kertesz et al., 1994; Black, 1996; Westbury and