Sleep-Related Declarative Memory Consolidation in Children and Adolescents with Developmental Dyslexia

Abstract

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.

Sleep Disturbances in Children with Attentional Deficit Hyperactivity Disorder and Specific Learning Disorders

“…It provides a total score and six subscale scores (see the materials and methods section for details), which can be used to identify a “personal sleep disturbance profile” and indicate whether there are dysfunctional areas that require further investigation [ 32 ]. For these reasons, it has already been widely used to assess sleep difficulties in various clinical populations (e.g., children with cerebral palsy [ 59 ]; children with epilepsy [ 60 , 61 ]; obese adolescents [ 62 ]; youth with juvenile idiopathic arthritis [ 63 ]), including specifically ADHD and SLD [ 18 , 22 , 62 , 64 , 65 , 66 ]. One of the previous studies using the SDSC in children with ADHD showed that they had difficulty initiating and maintaining sleep, sleep–wake transition, and excessive sleepiness [ 18 ].…”

“…In children with SLD, studies using the SDSC are very sporadic and have yielded mixed results: Some studies have documented problems with initiating and maintaining sleep, sleep breathing, and arousal [ 64 ], while others have found no difficulties [ 22 ].…”

“…In children with SLD, the effects of sleep difficulties on cognition are less well known. In a recent study [ 22 ], no relationship was found between sleep parameters such as slow-wave activity and novel word recall in children with reading difficulties, unlike in typical readers [ 23 ]. However, a relationship between reduced sleep spindles and difficulty in recall has been found in children with reading difficulties [ 22 ].…”

“…Importantly, these indices were correlated with the degree of reading impairment. In more recent studies, the association between sleep patterns and learning problems in children with reading difficulties has also been demonstrated [ 22 , 23 ].…”

Pengaruh Disleksia terhadap Perkembangan Anak

“…Khususnya, yang menyangkut memori deklaratif dan manfaat dari tidur dalam integrasi informasi baru telah banyak dibuktikan pada orang dewasa. Dua ciri sleep EEG Non-Rapid Eye Movement (NREM) telah diakui terutama yang terlibat dalam konsolidasi memori deklaratif: Slow Wave Activity (SWA) dan sleep spindle (Gorgoni Reda F, 2021).…”