Insights into the multi-factorial nature of reading difficulties: exploring phonological, visual, and attentional challenges in children.

This study investigates the interaction of auditory, visual, and attentional processing differences in children with and without reading difficulties, challenging the traditional view of developmental dyslexia (DD) as solely a phonological disorder. We examined multiple theoretical frameworks, including attentional processing, temporal processing, and noise exclusion theories, to provide a comprehensive understanding of cognitive challenges associated with DD. Ninety-seven Dutch-speaking children were assessed on tasks measuring reading, phonological and orthographic skills, as well as auditory and visual sensory-perceptual and attentional processing. Participants were categorised as Typical or Poor Readers based on standardised reading performance. Significant group differences emerged only in reading-related tasks (i.e., rapid naming, phoneme deletion, orthographic processing and the perception of text in noise). However, individual-level and dimensional analyses revealed a more complex picture. Individual deviance analysis revealed that while a subsample of poor readers exhibited no sensory-perceptual and attentional impairments, some showed selective difficulties in temporal, attentional, or noise exclusion tasks, underscoring the heterogeneity of their cognitive profiles. Principal component analysis identified four cognitive components: (i) reading-related skills and IQ in which phonological and orthographic processing are involved; (ii) rapid naming and visual temporal processing; (iii) multi-sensory sluggish attentional shifting involving phonological awareness; and (iv) multi-sensory cognitive control. Interestingly, regression analyses showed that visual temporal processing uniquely predicted reading and spelling, beyond phonological and orthographical skills. Mediation analysis further revealed that visual temporal processing influenced reading skill via rapid naming. These insights support a multi-factorial view of DD, emphasising the necessity for individualised interventions targeting varied and interacting cognitive difficulties.