Characteristics of interoceptive heartbeat accuracy, sensibility, and awareness in adults who stutter

Evidence suggests an association between interoceptive processing, which originates from feelings in the body, and mental health-related status, such as anxiety. We assessed heartbeat interoceptive accuracy, interoceptive sensibility, and awareness among 26 adults who stutter (AWS) and 26 those who do not stutter (AWNS) as controls. Heartbeat perception accuracy was measured via a heartbeat-tracking task in which participants counted their heartbeats in six trials of varying durations. Interoceptive sensibility was assessed via interoception questionnaires, which included the Body Perception Questionnaire and Multidimensional Assessment of Interoceptive Awareness. The area under the curve (AUC) in the heartbeat-discrimination task, in which participants judged the synchronization of their heartbeat and 10 tones with synchronized/not synchronized timing, was used to calculate interoceptive awareness. Interoceptive trait prediction error (ITPE) was also calculated via the Z-score differences between behavioral accuracy and self-reported sensibility. Our findings revealed significant differences in the interoception questionnaire scores (p = .013), which indicated a unique interoceptive pattern in AWS. Although no significant differences were observed in heartbeat-tracking performance (p = .188) and AUC (p = .131), a significant difference was observed in ITPE (p = .013), which suggested that AWS exhibited superior heartbeat perception accuracy compared with AWNS. Our study, the first to investigate multidimensional interoception in AWS, revealed distinct interoceptive patterns. These patterns were not explained by participants' age, co-occurring disorders scores, or stuttering severity, which indicated the need for further research to understand the relevance of interoception in stuttering mechanisms, anticipation, and treatment.