Multisensory Spatial Attention Deficits Are Predictive of Phonological Decoding Skills in Developmental Dyslexia

TLDR

Developmental dyslexia is traditionally linked to phonological deficits, yet evidence indicates that lower‑level sensory and attentional impairments, particularly in spatial attention, also contribute to reading difficulties. This study aimed to examine exogenous spatial attention in dyslexic children versus controls. Participants completed visual and auditory cued‑detection tasks while reaction times were recorded. Dyslexics with poor nonword decoding exhibited delayed multisensory spatial attention, which explained 31 % of unique variance in decoding performance and suggests that temporoparietal dysfunction‑related sluggish attention shifting impairs sublexical reading processes, offering a potential target for early identification and remediation.

Abstract

Although the dominant approach posits that developmental dyslexia arises from deficits in systems that are exclusively linguistic in nature (i.e., phonological deficit theory), dyslexics show a variety of lower level deficits in sensory and attentional processing. Although their link to the reading disorder remains contentious, recent empirical and computational studies suggest that spatial attention plays an important role in phonological decoding. The present behavioral study investigated exogenous spatial attention in dyslexic children and matched controls by measuring RTs to visual and auditory stimuli in cued-detection tasks. Dyslexics with poor nonword decoding accuracy showed a slower time course of visual and auditory (multisensory) spatial attention compared with both chronological age and reading level controls as well as compared with dyslexics with slow but accurate nonword decoding. Individual differences in the time course of multisensory spatial attention accounted for 31% of unique variance in the nonword reading performance of the entire dyslexic sample after controlling for age, IQ, and phonological skills. The present study suggests that multisensory "sluggish attention shifting"-related to a temporoparietal dysfunction-selectively impairs the sublexical mechanisms that are critical for reading development. These findings may offer a new approach for early identification and remediation of developmental dyslexia.