Linguistic and discourse level investigation of natural disfluencies in narrative samples of healthy adults

Word-finding difficulties are considered to be one of the earliest clinical manifestations of dementias such as Alzheimer's disease and primary progressive aphasia and have a similar clinical appearance to natural disfluencies in healthy individuals. Therefore, the study of agerelated changes in natural disfluencies is of great importance to distinguish healthy aging from neurodegeneration. This study analyzed the contexts in which natural disfluencies frequently occur in the narrative samples of 30 healthy individuals between the ages of 20-25. MoCATR was applied to show that the participants were cognitively healthy individuals. Narrative samples were collected using the story "Frog, Where are you?" and analyzed for suprasegmental parameters and microstructural features using SALT-TR software. In the study, the use of '-(y)I','-(y)A','-DA','-DAn' case suffixes and the use of verbs as microstructural features; and the frequency of enrichment, intonation, speech, and interjections as suprasegmental parameters were examined. In the presence of all microstructural and suprasegmental elements analyzed in the study, the number of natural disfluencies was statistically different (p < .001). In the findings, the suffix '-(y)A' has the highest natural disfluency requirement (Rank Mean = 7.22), whereas exclamation and speech contexts have the lowest natural disfluency behaviors (Rank Mean = 3.33). In Turkish, case suffixes increase the cognitive load and increase the occurrence of natural disfluency behaviors because they indicate position and direction. It was concluded that suprasegmental elements have a reducing effect on natural disfluency behaviors.