Differences between neurodegenerative disorders in conversational turn‐taking

Background A smooth turn‐taking transition from one person to the next is an expected part of many conversations. Turn‐taking combines high temporal coordination between participants with the remarkable complexity and open‐endedness of the language and paralanguage that fills the turns. Turn‐taking may therefore serve as a naturally occurring marker of disorders that disrupt executive functioning, ability to interpret nonverbal cues, as well as social drive and motivation. Methods Couples consisting of a healthy control and a person with a neurodegenerative condition were instructed to discuss a mutually selected topic of continuing disagreement in their relationship. Each conversation lasted between 10 to 15 minutes. Manual labeling of speakers, non‐speech vocalizations and background noise was then performed using Praat. Statistical analysis was then performed on numerous conversational metrics, including both count and duration of gaps, interruptions, and pauses throughout the conversations. Results Overall differences were found in number of times someone took the floor, interrupted the partner, and number of perfect exchanges. Compared to Alzheimer’s disease (AD), the semantic variant of primary progressive aphasia (svPPA) and progressive supranuclear palsy had more interruptions. Behavioral variant frontotemporal dementia had fewer perfect exchanges (< 0.1 second between speakers without interruption) than AD. Conclusion Floor exchanges, specifically numbers of interruptions and “perfect exchanges,” may be useful in distinguishing atypical AD from other dementia types. Next steps include comparing patients with neurodegenerative conditions against normal controls and correlating data with imaging and neuropsychiatric testing.