Neuroanatomical correlates of language impairment in non-fluent variant of primary progressive aphasia

Among the structural correlates, the most common were inferior frontal gyrus (was associated with fluency, both expressive and receptive agrammatisms) and supramarginal gyrus (apraxia of speech, receptive agrammatisms, naming and repetition). Apart from that, neuroanatomical foundations were different for each of the core nfvPPA language domains, including superior parietal lobule involvement in fluency, temporoparietal areas in receptive agrammatisms and supplemental motor area in apraxia of speech. Functional correlations were even more diverse. In general, connectivity decrease between temporoparietal structures was more typical for expressive and receptive agrammatisms, single word comprehension and naming, while apraxia of speech, fluency and repetition showed connectivity disruption mainly among the frontoparietal region and subcortical structures. Overall, extensive structural and functional changes are involved in the development of language and speech disturbances in nfvPPA with distinctive neuroanatomical foundations for each domain.