Search Abstracts | Symposia | Slide Sessions | Poster Sessions
White matter associations with word and pseudoword spelling in younger and older adults
Poster Session C, Thursday, October 1, 10:45 am - 12:45 pm, Wangari Maathai
Romi Sagi1, Robert Wiley2, Brenda Rapp3, Michal Ben-Shachar1; 1Bar-Ilan University, 2University of North Carolina at Greensboro, 3Johns Hopkins University
Producing written words is fundamental in everyday communication, but studies of the neural pathways supporting spelling are scarce. Only a handful of diffusion MRI studies examine white matter associations with word-spelling, primarily in healthy young adults and in individuals with developmental spelling disorders. These studies indicate that spelling depends on ventral and dorsal language-related pathways, as well as on cerebellar pathways (Gebauer et al., 2012; Banfi et al., 2019; Cheema et al., 2022; Sagi et al., 2024, 2025). It may be reasoned that lexical spelling processes rely primarily on ventral pathways, whereas sublexical phoneme-to-grapheme conversion relies more on dorsal pathways. This raises the hypothesis that pseudoword spelling would be associated with dorsal pathways. Yet pseudoword spelling remains largely unexplored in prior white matter studies. Moreover, little is known regarding how spelling associations are affected by aging. Here, we assessed white matter associations with real-word and pseudoword spelling performance, in younger and older adults. Forty-four healthy English-speaking adults completed a cognitive battery, including real-word spelling (WRAT3) and pseudoword spelling tests (N=22 in each age group, mean age 21y±3.9 and 67±5.5, respectively). We used constrained spherical deconvolution and probabilistic tractography to identify bilateral dorsal, ventral, and cerebellar tracts in each participant: the arcuate fasciculus, superior longitudinal fasciculus-III (SLF-III), inferior longitudinal fasciculus (ILF), and superior cerebellar peduncle. Fractional anisotropy (FA) and mean diffusivity (MD) were quantified along each tract, and correlations were assessed between tract microstructure and spelling performance. Real-word spelling performance was slightly better for older adults than younger adults (p=.046), while pseudoword spelling did not differ significantly between groups (p=.40). Consistent with prior findings, word spelling performance was associated with left ventral and right dorsal pathways. First, WRAT3 scores were significantly correlated with FA in the left ILF across the full sample while controlling for age (r=-.34, p=.026). Additionally, WRAT3 scores were significantly correlated with FA in the right SLF-III in young adults (r=-.51, p=.016). This association was not observed in older adults, and a regression analysis revealed a significant Group×Tract interaction, indicating age-group differences in the relationship between word-spelling and right SLF-III microstructure (β=-2.88, p=.031). Analyses of pseudoword spelling revealed associations only with dorsal tracts. In young adults, pseudoword spelling scores were significantly correlated with FA in the bilateral arcuate fasciculi (r_Left=-.74, r_Right=-.58, p<.01, FDR controlled at q<.05), as well as with MD in the bilateral arcuate fasciculi and bilateral SLF-III (rs>.60, p<.01, FDR controlled at q<.05). These associations were not observed in older adults. Regression analyses further revealed significant Group×Tract interactions for pseudoword spelling and dorsal tract microstructure (p<.05). These findings replicate prior findings linking real-word spelling performance in healthy young adults to specific ventral and dorsal language-related pathways. Results from pseudoword-spelling lend further support to the hypothesis that sublexical spelling relies on dorsal language-related pathways, consistent with their established involvement in sublexical reading and phonological awareness tasks. Importantly, although significant tract–behavior associations were not observed in older adults, significant interactions between tract microstructure and age-group suggest that the neural architecture supporting written word production changes with age.
Topic Areas: Writing and Spelling, Reading