Subcortical brain iron and its link to verbal memory in children with developmental language disorder

Abstract

Developmental Language Disorder (DLD) is a common neurodevelopmental condition characterized by significant difficulty with language learning, comprehension, and expression. The neurocognitive bases of DLD are underspecified but are thought to be related, in part, to altered basal ganglia (BG). The BG are known to have a high level of brain iron, which contributes to myelination and dopaminergic pathways among other physiological mechanisms. In this study, we investigated whether a brain iron imbalance might contribute to the altered BG function that characterizes individuals with DLD. Using a T2*-weighted signal, we compared BG brain iron levels in 7-to-13-year olds with DLD and typical language development (TD). We found a significant age-by-group interaction in the caudate with children with DLD showing a positive association between brain iron and age, which was not the case in TD children. A sex-by-age-by-group interaction was also reported in the right putamen and right nucleus accumbens. Higher brain iron in the caudate was associated with poorer story recall; there was no relation between brain iron levels and recall of word lists. This first-ever investigation of brain iron levels in individuals with DLD provides preliminary evidence of an abnormal developmental trajectory of brain iron balance and offers a potential explanation for the altered BG function and verbal impairments that characterize DLD.