A diagnosis of PPA required progressive deterioration of speech and/or language functions, and that deficits be largely restricted to speech and/or language for at least two years (Mesulam, 2001 (link)). Patients were diagnosed with the non-fluent variant of PPA based on new consensus guidelines (Gorno-Tempini et al., 2010 ). The non-fluent variant criteria require the presence of one or both of two core features: agrammatism, and/or effortful speech. Additionally, at least two of three supporting features must be present: comprehension deficits for syntactically complex sentences, spared single word comprehension, and/or spared object knowledge. Neuroimaging results were not used for diagnostic purposes, but only to rule out other causes of focal brain damage.
Additional inclusion criteria were fluency in English, and a Mini-Mental State Examination score of at least 15. Nine patients met these criteria and were scanned, but one was excluded since she performed at chance on all conditions including those that required lexical knowledge alone (see below), so all analyses were based on the remaining eight patients.
Two of the eight patients were severely agrammatic in their speech production (e.g. and uh a blanket… and… a thongs off the man… and um… uh… teenagers um… in the kite), two were moderately so (e.g. the family is have a picnic, and um, the young son is flying their kei- k- kite), one was near-mute with severely agrammatic written language (e.g. man read book girl the coffee in cup), one was near-mute with moderately agrammatic written language (e.g. the couple having a picnic, they are sitting a blanket under a tree), and two had primarily speech motor deficits, with intact syntax in production (e.g. the fellow is reading a book, the woman is pouring some l- liquids), and mild syntactic deficits evident only in comprehension of complex sentences. All patients were clinically diagnosed with apraxia of speech, with severity ranging from 2 to 7 on a 7-point scale (Wertz et al., 1984 ), and 4 of the 8 were dysarthric (including the two who were near-mute).
Demographic, clinical and neuropsychological characteristics for all participants are provided in
In addition to the 24 normal controls who took part in functional imaging, structural images from another group of 50 healthy age-matched controls were used to create a template for intersubject normalization and voxel-based morphometry.