Memória de trabalho e destreza manual de crianças e adolescentes com dislexia: revisão sistemática e metanálise

Abstract

Introduction: Dyslexic children usually have impairments in a range of skills, such as phonological awareness, phonological coding, spelling deficits, working memory, sequencing, poor balance and delays in motor milestones, speed, accuracy and automation, in addition to difficulties in fine motor tasks and writing skills. Several hypotheses try to explain the cognitive and motor problems related to dyslexia, however, there is still a gap in this area that does not make it clear which the subjacent factors are for this disorder. However, studies have shown that when cognitive development is disturbed, as in working memory, motor development is often adversely affected, especially the manual dexterity, which allows us to infer the possibility that both areas interfering with each other's proper functioning. Objective: To perform a systematic review and meta-analysis to investigate working memory skills and manual dexterity and the existence of a relationship between alterations in these two skills in dyslexic children and adolescents. Methods: The elaboration and protocol of this review were carried out according to the criteria established by Preferred Reporting for Systematic Reviews and Meta-analyzes (PRISMA). Six literature databases were searched to locate studies published between 2000 and 2020: EMBASE, ERIC, ISI Web of Science, PubMed, PsycINFO and Scopus databases. Eligibility criteria and methodological quality were independently assessed by two reviewers. The meta-analysis was performed using the “rma.mv” function of the Metafor package in R version 4.1.0. Results: A total of 167 studies were found, 21 of them fit the inclusion criteria. The results were obtained from the data of these 21 studies that included a total of 3129 participants in which sample sizes ranged from 24 to 893 and the mean age was 10.69 years of age, standard deviation 1.53. The results are presented in forest plots in which the difference between groups in each study is represented by a square. Conclusions: The results suggest that dyslexic children have significantly poorer visuospatial and verbal working memory, with more impairments in the phonological loop. Although differences were observed in fine motor control skills, handwriting and manual motor speed, these differences were not significant between groups. Neural correlates between working memory and manual dexterity were observed, indicating that dyslexic children exhibited dysfunction in the connectivity between brain areas to cognitive and motor processes during the writing process.