Sleep-Related Declarative Memory Consolidation in Children and Adolescents with Developmental Dyslexia
Sleep has a crucial role in memory processes, and maturational changes in sleep electrophysiology
are involved in cognitive development. Albeit both sleep and memory alterations have
been observed in Developmental Dyslexia (DD), their relation in this population has been scarcely
investigated, particularly concerning topographical aspects. The study aimed to compare sleep
topography and associated sleep-related declarative memory consolidation in participants with DD
and normal readers (NR). Eleven participants with DD and 18 NR (9–14 years old) underwent a
whole-night polysomnography. They were administered a word pair task before and after sleep to
assess for declarative memory consolidation. Memory performance and sleep features (macro and
microstructural) were compared between the groups, and the intercorrelations between consolidation
rate and sleep measures were assessed. DD showed a deeper worsening in memory after sleep
compared to NR and reduced slow spindles in occipito-parietal and left fronto-central areas. Our
results suggest specific alterations in local sleep EEG (i.e., sleep spindles) and in sleep-dependent
memory consolidation processes in DD.We highlight the importance of a topographical approach,
which might shed light on potential alteration in regional cortical oscillation dynamics in DD. The
latter might represent a target for therapeutic interventions aimed at enhancing cognitive functioning
in DD.