Dyslexia as the most prevalent form of specific learning disabilities

Abstract

Dyslexia is the most common form of specific learning disabilities. Dyslexia is observed in 5-17.5 % of schoolchildren, and among children with specific learning disabilities, it accounts for about 70-80 %. Usually, dyslexia manifests itself as the inability to achieve an appropriate level of reading skills development that would be proportional to their intellectual abilities and writing and spelling skills. Secondary consequences of dyslexia may include problems in reading comprehension and reduced reading experience that can impede the growth of vocabulary and background skills. The review discusses neurological management of reading and writing as complex higher mental functions, including many components that are provided by various brain areas. The principles of dyslexia classification, the main characteristics of its traditionally defined forms are given: phonemic, optical, mnestic, semantic, agrammatic. The article analyzes the cerebral mechanisms of dyslexia development, the results of studies using neuropsychological methods, functional neuroimaging, and the study of the brain connectome. The contribution to dyslexia development of disturbances in phonological awareness, rapid automated naming (RAN), the volume of visual attention (VAS), components of the brain executive functions is discussed. The origin of emotional disorders in children with dyslexia, risk factors for dyslexia development (including genetic predisposition) are considered. Dyslexia manifestations in children are listed, about which their parents seek the advice of a specialist for the first time. In the process of diagnosing dyslexia, attention should be paid to the delay in the child’s speech development, cases of speech and language development disorders and specific learning disabilities among family members. It is necessary to consider possible comorbidity of dyslexia in a child with attention deficit hyperactivity disorder, dyscalculia, developmental dyspraxia, disorders of emotional control and brain executive functions. Timely diagnosis determines the effectiveness of early intervention programs based on an integrated multimodal approach.