Search Abstracts | Symposia | Slide Sessions | Poster Sessions
Altered precentral inter-effector area morphometry and functional connectivity in children who stutter
Poster Session B, Wednesday, September 30, 4:30 - 6:30 pm, Wangari Maathai
Ci-Jun Gao1, Yanni Liu1, Emily O. Garnett1, Soo-Eun Chang1; 1University of Michigan
Stuttering is a neurodevelopmental speech motor disorder affecting approximately 5–8% of individuals. Prior work has implicated multiple neural circuits, including the cortico–basal ganglia–thalamocortical loop and laryngeal motor regions. In adults who stutter, ventral and dorsal laryngeal motor regions show distinct associations with stuttering persistence and recovery, but whether similar dissociations occur in childhood remains unclear. Inter-effector areas (IEAs; Gordon et al., 2023) within the precentral cortex provide a new anatomical framework for studying speech-motor network organization. These regions are interleaved with effector-specific motor areas and show connectivity with cingulo-opercular, subcortical, and cerebellar systems. Because inferior and middle IEAs overlap with ventral and dorsal laryngeal motor regions, respectively, they may help integrate laryngeal motor and basal ganglia accounts of developmental stuttering. We examined morphometry and resting-state functional connectivity of bilateral inferior and middle IEAs in children who stutter (CWS), comparing persistent and recovered CWS (pCWS, rCWS), and controls. We hypothesized that persistent stuttering would be associated with altered structure and connectivity, especially involving default-mode and subcortical motor networks; that the inferior IEA would be most consistently implicated in cortical connectivity differences; that connectivity alterations would relate to stuttering severity; and that morphometric and functional measures would show distinct developmental profiles. Participants included 167 children ages 3–12 years (52 pCWS, 27 rCWS, 88 controls) who contributed morphometric data across 362 scans. A subset of those children (n=158; 50 pCWS, 24 rCWS, 84 controls) also contributed resting-state fMRI data across 334 scans. Bilateral inferior and middle IEA seeds were defined using the Somato-Cognitive Action Network atlas. Cortical thickness and local gyrification index (LGI) were analyzed using linear mixed-effects models (LMMs) with group, age, sex, and IQ as fixed effects and subject as a random intercept. Resting-state functional connectivity maps were tested using whole-brain grayordinate-wise group contrasts with cluster-extent family-wise error correction. Significant clusters were further examined for group effects, associations with stuttering severity, and age-stratified effects in preschool- (3–5 years) and school-age (6–12 years) children. Children with persistent stuttering showed bilateral morphometric anomalies, including reduced thickness in the left inferior, right middle, and right inferior inter-effector areas, and increased LGI in the left inferior IEA (all q=0.040). No significant age-by-group interactions were found for morphometry. Functional connectivity analyses revealed two main patterns. Cortically, the right inferior IEA showed increased connectivity with posterior default mode network (DMN) regions in CWS relative to controls, with this hyperconnectivity strongest in pCWS (pCWS>controls, q<0.001; pCWS>rCWS, q<0.01). Subcortically, IEA seeds, especially middle IEA, showed reduced connectivity with right caudate, putamen, and thalamic regions in both persistent and recovered CWS relative to controls (q<0.01). Within CWS, greater stuttering severity was associated with stronger right IEA connectivity with default mode network regions and the right putamen (q=0.035). Age-stratified analyses suggested that IEA-DMN and IEA-subcortical differences were most evident in school-age children. These findings suggest that childhood stuttering involves altered IEA structure and connectivity with both cortical and subcortical networks. Inter-effector areas may provide an integrative framework linking laryngeal motor and basal ganglia timing mechanisms in developmental stuttering.
Topic Areas: Speech Motor Control, Disorders: Developmental