Adaptive compensation of arcuate fasciculus lateralization in developmental dyslexia

Previous studies have reported anomalies in the arcuate fasciculus (AF) lateralization in developmental dyslexia (DD). Still, the relationship between AF lateralization and literacy skills in DD remains largely unknown. The purpose of our study is to investigate the relationship between lateralization of three segments of AF (AF anterior segment (AFAS), AF long segment (AFLS), and AF posterior segment (AFPS)) and literacy skills in DD. A total of 26 children with dyslexia and 31 age-matched control children were included in this study. High angular diffusion imaging, combined with spherical deconvolution tractography, was used to reconstruct the AF. Connectivity measures of hindrance-modulated orientational anisotropy (HMOA) were computed for each of the three segments of the AF. The lateralization index (LI) of each AF segment was calculated by (right HMOA - left HMOA)/(right HMOA thorn left HMOA). Results showed that the LIs of AFAS and AFLS were positively correlated with reading accuracy in children with dyslexia. Specifically, the LI of AFAS was positively correlated with nonword and meaningless text reading accuracy, while the LI of AFLS accounted for word reading accuracy. The results suggest adaptive compensation of arcuate fasciculus lateralization in developmental dyslexia and functional dissociation of the anterior segment and long segment in the compensation. (c) 2023 Elsevier Ltd. All rights reserved.

Automated summary

This study investigates the relationship between lateralization of three segments of the arcuate fasciculus (AF) and literacy skills in developmental dyslexia. The results show that the lateralization index (LI) of the anterior segment (AFAS) and long segment (AFLS) are positively correlated with reading accuracy in children with dyslexia. Specifically, the LI of AFAS is correlated with nonword and meaningless text reading accuracy, while the LI of AFLS is associated with word reading accuracy. The findings suggest adaptive compensation and functional dissociation of AF lateralization in developmental dyslexia.