The Symptoms of Dyslexia and Their Assessment Tools – the Current State of Knowledge

This article aims to present the current state of knowledge on the assessment of dyslexia: its symptoms and assessment tools, following the idea of promoting research-based practice. During the assessment, the level of development of reading accuracy and fluency should be measured: decoding, word recognition, and reading comprehension. Spelling can also be evaluated, as dyslexia and dysorthography are essentially caused by the same factors. When spelling, children with dyslexia, as compared with their peers without dyslexia, make more errors (a quantitative difference), but of the same types (no qualitative difference). These errors can be classified into phonological and orthographic ones. Moreover, the cognitive abilities and skills contributing to the typical development of reading should be assessed: phonological awareness, verbal working memory, rapid automatised naming (i.e. phonological processing skills), vocabulary, and general knowledge. A diagnosis of dyslexia can be made not only in children with normal intellectual development, but also in children with borderline intellectual functioning (only intellectual disability is an exclusion factor). Dyslexia co-occurs with other neurodevelopmental disorders, e.g. attention deficit hyperactivity disorder, autism spectrum disorder, developmental language disorder, developmental speech disorder, and developmental motor coordination disorder. The latter disorder, which includes dysgraphia, is not part of the developmental dyslexia syndrome, but only co-occurs with dyslexia.