Age and Discourse Task Independently Influence Disfluency Production.

PURPOSE: Aging is often associated with increased difficulty in speech production (e.g., increased word-finding difficulties and disfluencies), as well as with broader cognitive changes such as declines in executive function (EF) and greater sensitivity to task constraints. However, how both EF and task constraints contribute to age-related differences in speech is unclear. METHOD: We analyzed age-related differences in disfluencies and lexical diversity in spontaneous speech from 272 healthy adults, aged 20-81 years, using two narrative discourse tasks varying in structure: an open-ended prompt and a picture book description. Both tasks involve telling a story but differ in predetermined structure. The open-ended prompt is unstructured, while the picture book provides visual scaffolding to guide speech. Additionally, participants completed a battery of EF tasks. RESULTS: Overall, older adults produced more repetitions, revisions, and unfilled pauses. Filled pauses, however, decreased with age, which may be related to generational differences in lexical filler use (e.g., "like," "you know"). Additionally, there was an effect of discourse task: The open-ended prompt elicited more disfluencies overall and higher lexical diversity, despite speech samples being shorter in duration and containing fewer words. Though older adults also showed lower EF across several tasks, relationships between EF, age, and disfluencies did not survive corrections for multiple comparisons suggesting a minimal influence of EF on disfluencies in this sample. CONCLUSIONS: These findings emphasize the influence of age and task demands on speech production. However, EF showed limited associations with disfluency production and did not account for age differences. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.33334365.