Abstract We investigated whether the difference between chronological and modeled brain age explains individual differences in language performance among healthy older adults. Age-related decline in language abilities is widely documented, with considerable variability among healthy older individuals in both language performance and underlying neural substrate. We derived predicted brain age from grey and white matter using machine learning and used this measure to estimate neurological deviations from chronological age. Using Bayesian mixed-effects modeling, we tested whether brain-age deviations predict language performance in a sample of 86 adults aged 60 years and above. We assessed the effect of brain-age deviations on performance across four well-established language processing tasks, each tapping into linguistic domains known to be vulnerable to ageing and show individual variability in skill levels, in both comprehension and production. Our findings suggest that, in healthy older individuals, predicted deviations of brain age from chronological age do not predict language abilities. This challenges the idea that brain age is a reliable determinant of language processing variability, at least in healthy (as opposed to pathological) ageing and highlights the need to consider other neural and cognitive factors when studying language decline.

We investigated the stability of word reading and/or spelling deficits in children from Sweden (N = 170) and the U.S. (N = 452) from the end of Grade 1 to Grade 2 and from Grade 2 to Grade 4. Children were assessed for reading fluency and spelling accuracy and classified into subtypes with isolated reading deficits (RD), isolated spelling deficits (SD) or combined deficits (RSD). Stability was assessed using cross-tabulations and chi-square or Fisher's exact tests. The RSD subtype showed moderate to high stability across grades, whilst RD and especially SD were significantly less stable. These patterns held across orthographies. Although single-timepoint identification of isolated deficits may justify monitoring and support, our findings suggest limited predictive value for long-term persistence. This challenges prior assumptions about the stability of dissociative profiles and underscores that most children with literacy difficulties experience challenges in both the accuracy and efficiency of accessing phonological and orthographic representations. The results have implications for theoretical models of literacy development and for designing interventions targeting early reading and spelling difficulties.