Presentation

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Reduced White Matter Integrity in Cantonese-Speaking Children with Developmental Language Disorder: Preliminary Evidence Supporting the Procedural Circuit Deficit Hypothesis

Poster Session B, Friday, October 25, 10:00 - 11:30 am, Great Hall 3 and 4

Xiaocong Chen¹, Jueyao Lin¹, Angel Chan¹, Michael Ullman², Min Ney Wong¹, Caicai Zhang¹; ¹The Hong Kong Polytechnic University, ²Georgetown University

Introduction: Developmental Language Disorder (DLD) affects various childhood language difficulties, though it notably impacts morphosyntax. The Procedural circuit Deficit Hypothesis (PDH; Ullman et al., 2020) posits that DLD may be largely explained by abnormalities of the basal-ganglia-based circuitry underlying procedural memory. Previous studies of the PDH have predominantly focused on English-speaking children and examined gray matter in the basal ganglia and associated circuitry (Ullman et al., 2024). Given the distinct linguistic characteristics of Chinese (e.g., sparse inflectional morphology and less informative structural sequence cues), this study focused on Cantonese-speaking school-age children with DLD and their age-matched typically developing (TD) peers. We examined microstructural differences in white matter tract integrity between the DLD and TD groups. Additionally, we investigated whether microstructural metrics predicted receptive grammar skills in these children, focusing on grammar comprehension, which has relatively few cognitive and motor confounds. Methods: Twenty-two native Cantonese-speaking children participated (11 DLD, 4 girls, 8.98±1.65 years old; 11 TD, 5 girls, 9.34±1.72 years old). Diffusion tensor imaging (DTI) was performed using a 3T SIEMENS system. Tract-Based Spatial Statistics (TBSS) and Region of Interests (ROI) analyses were conducted to identify group differences in fractional anisotropy (FA) values of major white matter tracts. Receptive grammar skills were assessed using a standardized grammar comprehension test. Results: TBSS analysis revealed some clusters of smaller FA values in DLD children than in TD children (ps <.05), particularly in parts of the corpus callosum and internal capsule. ROI analyses also suggested that DLD children had reduced mean FA values in the splenium and genu of the corpus callosum, and in the bilateral anterior and posterior limbs of internal capsule (ps <.1). After controlling for age, gender, and non-verbal IQ, regression analyses revealed that the mean FA values of the splenium and genu of corpus callosum and the bilateral posterior limbs of internal capsule, were significant positive predictors of the receptive grammar scores (with two groups collapsed; ps<.05), while the mean FA values of the bilateral anterior limbs of internal capsule were marginally significant positive predictors of the receptive grammar scores (ps <.1). Conclusion: Consistent with Lee et al. (2020), these preliminary results support the PDH by showing reduced structural integrity (i.e., smaller FA values) in the DLD group compared to the TD group in the bilateral anterior and posterior limbs of internal capsule. The internal capsule, a prominent white matter structure in the corticostriatal system, connects the cortex and basal ganglia, with its anterior limb linking to the prefrontal cortex and the posterior limb to motor and sensory cortices. Additionally, the significantly smaller FA values of the splenium and genu of the corpus callosum align with previous DTI studies on DLD, suggesting poorer inter-hemispheric information integration in this population (Kim et al., 2006; Paul, 2011). These findings enhance our understanding of the neural substrate of DLD and may have therapeutic implications for the disorder.

Topic Areas: Disorders: Developmental, Language Development/Acquisition