Assessing informativeness in Spanish-speaking individuals with primary progressive aphasia

Abstract

ABSTRACT Background Primary progressive aphasia (PPA) is a neurodegenerative disorder associated with atrophy of the frontotemporal region. It is primarily characterized by language impairments that become accentuated over time, often leading to isolation and social exclusion. There are three main subtypes, the semantic (svPPA), non-fluent (nfvPPA), and logopenic (lvPPA) variants, each presenting distinct language deficits, as captured by standard assessment batteries. However, such assessments often fail to adequately identify functional communication (dis)abilities in everyday life, which is crucial for effective diagnosis and treatment. One understudied aspect of communication is informativeness, the conveyance of an appropriate amount of information in an efficient fashion. Aim This study aimed to identify the unique features of each variant of PPA that distinguish it from healthy controls, and the dissimilarity across PPA groups, in terms of the effectiveness and efficiency with which Spanish-speaking individuals with PPA conveyed information. Methods and procedures Thirty-two Spanish-speaking patients with one of the three variants of PPA and 11 healthy individuals were audio-recorded performing a picture description task. The resulting recordings were transcribed, and the contents labelled according to whether they constituted relevant or off-topic content, each type of content being further divided into subcategories. In total, 51 parameters related to the (1) overall amount of speech and number of correct information units, (2) amount of relevant content, (3) completeness of the content, and (4) off-topic information were considered. Nonparametric analyses were conducted to assess the divergence from heathy controls of each PPA group, and the dissimilarity across PPA groups. Outcomes and results Results revealed disruptions in informativeness in all PPA variants compared to controls, with lvPPA characterized by inadequate content and a high concentration of off-topic elements, nfvPPA by inadequate content but efficient delivery, and svPPA by inadequate content delivered inefficiently. Conclusions This study revealed that all three variants of PPA are characterized by reduced informativeness, although each exhibits unique patterns in communicative efficiency and the presence of off-topic information. By assessing the total amount of relevant speech, efficiency in conveying content, and the presence of off-topic elements, this research enhances our understanding of the distinct communication impairments characterizing lvPPA, nfvPPA, and svPPA, and provides valuable insights that can be applied to developing tailored remedial strategies.