Connected speech production in the nonfluent variant of primary progressive aphasia and its relationship with white matter damage (P1.228)

Objective. Aim of this study is to investigate the association between the different components of the connected speech and white matter (WM) tract damage in nonfluent variant of primary progressive aphasia (nfvPPA). Background. Several components of the connected speech recorded in patients with PPA have been associated with specific patterns of gray matter (GM) atrophy. A growing number of studies is revealing the importance of WM damage in PPA. Methods. To assess the connected speech, we recorded speech samples from 11 nfvPPA patients while they described the image of the picnic picture subtest of the Western Aphasia Battery and analyzed them considering: lexical production rate and phonological/articulatory errors; pauses and repetitions; lexical typology; and syntactic structure. Diffusion tensor (DT) MRI metrics were obtained from the interhemispheric and major association WM tracts. Results. Speech samples in nfvPPA patients were characterized by slow rate, distortions, syntactic errors and reduced complexity of sentence production. The lexical production rate was positively related with the integrity of the left superior longitudinal (SLF) and inferior longitudinal (ILF) fasciculi and cingulum bilaterally; the Italian phoneme distortions were related with damage of the corticospinal tracts; the false starts were related with damage of the corpus callosum (CC); the lexical selection (such as the use of nouns, verbs, or prepositions) was related with DT MRI metrics of left SLF and CC genu; the syntactic complexity (i.e., mean length of utterance, ratio between number of words per sentence and number of sentences) and presence of morpho-syntactic errors were related with damage of the left SLF and ILF, and CC body. Conclusions. We reported associations between particular aspects of connected speech and damage to specific WM tracts in nfvPPA. This study underlines the relevant role of WM in nfvPPA. Funding. Italian Ministry of Health (GR#2010-2303035).