Presentation
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Corpus callosum development in children who stutter
Poster E63 in Poster Session E, Thursday, October 26, 10:15 am - 12:00 pm CEST, Espace Vieux-Port
Fiona Höbler1, Ho Ming Chow2, Emily O. Garnett1, Yanni Liu1, Soo-Eun Chang1; 1University of Michigan, 2University of Delaware
Introduction: The corpus callosum (CC) supports interhemispheric communication and cerebral specialization through lateralization of human motor and language systems. Among adults who stutter, atypical hemispheric lateralization has been identified in regions associated with language and motor functioning, as well as differences in white matter volume and fractional anisotropy (FA) in anterior and posterior regions of the CC. Reduced FA values have recently been identified in the anterior CC of neonates at risk of stuttering, while an overall reduced growth rate of FA was found in children with persistent stuttering compared to those who recovered. This study investigated CC development in children who do (CWS) and children who do not stutter (CNS). We hypothesized that, when compared to CNS, CWS would show reduced growth rate of FA in anterior CC segments associated with motor regions, as well as in posterior segments associated with auditory and somatosensory communication across hemispheres, with potential differences in posterior development being associated with stuttering persistence. Methods: Participants included 172 children between 3-12 years of age (81 CWS, 38 females; 91 CNS, 44 females), with CWS categorized as persistent (CWS-P; n=62) or recovered (CWS-R; n=19). Children were scanned yearly up to 4 times, resulting in 431 datasets with useable DTI and structural MRI data. Diffusion weighted imaging data were preprocessed using MRtrix and individual FA values > 0.25 were projected to a white matter skeleton using FSL’s tract-based spatial statistics algorithm. We divided the CC into 5 equal segments along the anterior-to-posterior (Y) axis (anterior, mid-anterior, central, mid-posterior, posterior). For each participant, voxel-wise FA values in each CC section were extracted and averaged using AFNI. Each CC sub-region was analyzed using linear mixed-effects models with interactive factors of group (CNS, CWS-R, and CWS-P) and age to investigate differences in FA growth rate. Sex, IQ, and SES were included as covariates. Individual variability was controlled for by treating participant as a random intercept. Results: Using LMM analyses we found that among children who persisted to stutter, FA values in the mid-posterior CC decreased with age (CWS-P x Age: p = .03). FA values tended to be larger in boys compared to girls in the mid-posterior CC (Sex M: p = .006). However, stratified analyses revealed significant decreases in FA values in both mid-posterior (p = .02) and central (p < .05) CC among female CWS-P. Summary: We found significant sex-based differences in WM development in the mid-posterior CC – a region of extended growth during childhood (Luders, Thompson, & Toga, 2010). Preliminary results showed that in CC regions reported to support communication between primary motor (central) and somatosensory cortices (mid-posterior), FA decreases were associated with stuttering persistence, most significantly for girls. This study will further explore the influence of stuttering severity on FA growth rate among CWS. The current findings lend further support to 1) possible inefficiencies in sensorimotor integration and motor control, and 2) atypical lateralization of sensory and motor functioning in persons who stutter, in which this commissural fiber tract plays a critical role.
Topic Areas: Disorders: Developmental, Speech Motor Control