Pause Characteristics by Utterance Position in Patients with Primary Progressive Aphasia Subtypes

Objectives: Primary progressive aphasia (PPA) is a neurodegenerative disease characterized by prominent language impairments within the first two years of onset. PPA is clinically categorized into three subtypes: semantic variant (svPPA), logopenic variant (lvPPA), and non-fluent/agrammatic variant (nfvPPA). Pauses that occur during speech production in primary progressive aphasia (PPA) can serve as simple and reliable biomarkers for subtype classification and early diagnosis of PPA. This study aimed to investigate the characteristics of pauses in PPA subtypes during a picture description task. Methods: The study included a total of 60 participants: 9 with semantic variant (svPPA), 19 with logopenic variant (lvPPA), 11 with nonfluent variant (nfvPPA), and 21 healthy controls. After transcribing the participants’ speech, their pause durations were measured using the acoustic analysis program, Praat. Pauses were categorized as inter-utterance, intra-utterance, inter-word, and intra-word pauses. Results: Among the three types of PPA, the nfvPPA manifested slower speech rates and longer pauses between utterances compared to the svPPA and lvPPA. Furthermore, the lvPPA showed longer pauses between words within utterances compared to the svPPA. Conclusion: This study found that speech rate and pause durations differed by subtype, with the nfvPPA showing effortful speech due to increased articulatory complexity, which is attributed to neuroanatomical insult. The lvPPA may utilize pauses to compensate for word retrieval deficits during speech production. This study is significant as it provides pause characteristics in speech across different PPA subtypes via acoustic analysis.