Longitudinal changes in connected speech over a one-year span in the nonfluent/agrammatic variant of Primary Progressive Aphasia

Abstract

Background Connected speech assessment is essential to characterize the language features in primary progressive aphasia (PPA). This is especially true for the non-fluent/agrammatic variant (nfvPPA) in which one of the core features is agrammatism. Identification of agrammatism typically involves the analysis of sentence production, as in connected speech, in order to detect syntactic deficits. However, little is known about the longitudinal changes occurring in connected speech of individuals with non-fluent PPA. Aim The aim of this study was to assess changes in connected speech over a one-year span in participants with nfvPPA using semi-structured interviews. Methods and procedures We conducted a prospective group study including participants with nfvPPA (n=9) and age- and education-matched healthy controls (n=9). For each individual, connected speech was obtained using topic-directed interviews at two testing rounds, each approximately one year apart. Production on each task was recorded, transcribed and analyzed according to the Quantitative Production Analysis (QPA) protocol, a tool developed by Berndt and colleagues (2000) for the analysis of sentence production in aphasia. For each group, the probability of deterioration between the two testing rounds was estimated using Bayesian analysis. Results and outcomes For individuals with nfvPPA, statistical evidence of deterioration from the first testing round to the second was found for five variables, namely the proportion of pronouns, the proportion of verbs, the proportion of closed class words, the inflection index and the proportion of well-formed sentences. Conclusions Results from the present study suggest that variables relating to word-finding and morphology are more vulnerable to time and therefore may be relevant potential targets for intervention.