White matter differences in college-educated dyslexic and control adults: A diffusion MRI study in Brazilian Portuguese speakers

IF 3.2 2区心理学 Q1 BEHAVIORAL SCIENCES

Cortex Pub Date : 2025-12-01 Epub Date: 2025-10-23 DOI:10.1016/j.cortex.2025.10.003

Bruce Martins , Edson Amaro , Ellison Fernando Cardoso , Katerina Lukasova , Mariana Penteado Nucci

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Abstract

The brain white matter microstructure of adult dyslexic readers is rarely studied, particularly in non-English speaking populations. This study investigated structural differences in white matter between Dyslexic and Control adults, all native Brazilian Portuguese speakers with a college-level education. We analyzed diffusion MRI data from 62 volunteers (26 with dyslexia and 36 controls), using deterministic and probabilistic approaches. Groups were matched for age, sex, handedness, and level of formal education. Deterministic analysis revealed significantly lower mean diffusivity and radial diffusivity in individuals with dyslexia in the posterior right hemisphere, particularly in core reading-related tracts such as the superior longitudinal fasciculus, inferior longitudinal fasciculus, and inferior fronto-occipital fasciculus. Probabilistic analysis showed widespread group differences in all diffusion measures investigated, including tracts not typically linked to dyslexia, and revealed alterations mainly in fractional anisotropy and radial diffusivity in posterior portions of tracts within the right hemisphere. Correlations between reading fluency and diffusion metrics revealed distinct neural behavioral patterns between groups, suggesting different neural mechanisms underlying reading abilities. These findings provide novel insights into white matter microstructure in dyslexia among Portuguese speakers and underscore the importance of cross-linguistic studies in reading disorders.

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受过大学教育的失读症患者和对照组成人的白质差异：巴西葡萄牙语者的扩散MRI研究

成人阅读困难读者的脑白质微观结构很少被研究，特别是在非英语人群中。这项研究调查了有阅读困难的成年人和正常成年人的白质结构差异，这些成年人都是母语为巴西葡萄牙语并受过大学教育的人。我们使用确定性和概率方法分析了62名志愿者（26名患有阅读障碍，36名对照）的扩散MRI数据。各组根据年龄、性别、惯用手和正规教育水平进行匹配。确定性分析显示，阅读障碍患者右脑后半球的平均扩散率和径向扩散率明显较低，尤其是核心阅读相关束，如上纵束、下纵束和额枕下束。概率分析显示，在所有研究的扩散测量中，包括与阅读障碍没有典型联系的神经束，存在广泛的组间差异，并揭示了右半球神经束后部的部分各向异性和径向扩散率的改变。阅读流畅性和扩散指标之间的相关性揭示了不同组间不同的神经行为模式，提示阅读能力背后的不同神经机制。这些发现为葡萄牙语使用者阅读障碍的白质微观结构提供了新的见解，并强调了跨语言研究在阅读障碍中的重要性。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Cortex 医学-行为科学

CiteScore

7.00

自引率

5.60%

发文量

250

审稿时长

74 days

期刊介绍： CORTEX is an international journal devoted to the study of cognition and of the relationship between the nervous system and mental processes, particularly as these are reflected in the behaviour of patients with acquired brain lesions, normal volunteers, children with typical and atypical development, and in the activation of brain regions and systems as recorded by functional neuroimaging techniques. It was founded in 1964 by Ennio De Renzi.