Anxiety and neurophysiological correlates of stuttering severity in adults who stutter

BACKGROUND: Stuttering has traditionally been conceptualized as a motor speech disorder; however, accumulating evidence suggests that auditory processing differences and emotional factors may also contribute to its clinical presentation. Despite increasing interest in these domains, the interplay between auditory cortical processing, stuttering severity, and anxiety in adults remains incompletely understood. OBJECTIVE: This study aimed to examine auditory evoked cortical responses (P1, N1, P2, and mismatch negativity [MMN]) in adults who stutter compared with fluent-speaking controls, and to explore how neurophysiological measures vary in relation to stuttering severity and state-trait anxiety levels. METHODS: Auditory event-related potentials were recorded using pure-tone stimuli in adults who stutter and age-matched control participants. Latency and amplitude measures of the P1, N1, P2, and MMN components were analyzed. Anxiety was assessed using the State-Trait Anxiety Inventory (STAI). Group comparisons and correlational analyses were performed to characterize neurophysiological, clinical, and psychological patterns. RESULTS: Compared with controls, adults who stutter exhibited significant alterations in both early (P1, N1) and later (P2, MMN) stages of auditory cortical processing. Increasing stuttering severity appeared to be associated with a pattern of variation in ERP latencies and amplitudes, accompanied by parallel changes in state, trait, and total anxiety scores. CONCLUSIONS: These findings suggest that stuttering in adulthood is associated with widespread differences in auditory cortical processing that co-vary with both anxiety levels and clinical severity. The results support a multidimensional framework in which sensory, emotional, and speech-related processes interact, highlighting the importance of integrated neurophysiological and psychological assessment approaches in stuttering research and clinical practice.