**3. Dyslexia and executive functions**

Evidence supports that executive functions are accompanied by learning difficulties (commonly known as learning disorder [LD]). In general, the first indicator of learning difficulty is the low rate of academic achievement in reading, mathematics, or writing [47–50].

Students with learning disabilities who have difficulty in planning, initiating activity, organizing thoughts and materials, self-monitoring and progression, impulse control, or attention shifting cannot learn as effectively as those who master these executive function skills [49]. While executive dysfunctions and learning disabilities often coexist, the relationship between executive dysfunctions and learning disability is still not fully established. A fundamental question is whether the specific characteristics of a particular academic field challenge are executive function difficulties or not. Even if there are no academic weaknesses, it is a bigger question to consider the difficulties of executive functioning as a learning disadvantage.

Phonological difficulties are seen as the greatest cause of reading difficulty, but the difficulty of executive functioning presents an additional difficulty in reading. A recent study has shown that children with dyslexia produce fewer words and complete fewer categorical tasks than typical readers in the semantic fluency task. In addition, in learning disorders, the metaanalyses of executive functions show that children with learning disabilities typically cannot achieve their peers' performance in executive function tests [51]. For example, a meta-analysis involving 48 studies, typically comparing the difficulties of executive functions on developing children with learning disability, attributed moderate (0.56) effect dimension on executive functions [52]. Wechsler intelligence scale for children- fourth edition (WISC-IV) Coding has distinguished and identified the participants with learning disability the most accurately from their typically developing peers. Similarly, the meta-analysis of 13 researchers comparing children with learning disorder and children with typical development has shown that the overall impact dimension which was measured by planning, organizing, strategy development, attention to detail, and recall tests for executive functions is moderate. Although verbal and visual working memory seems to be effective, verbal working memory has been shown to be more effective than visual working memory [53–56]. It is seen that the difference between the subjects with reading difficulty and typical readers increases with age. Overall, findings suggest a strong association between learning disability and executive functions [49, 57, 58].

Some studies have investigated the difficulties of executive functioning in subtypes of reading disorders. In particular, researchers compared the difficulty of reading a word with the difficulty of understanding reading. For example, in one study, adolescents were categorized as difficulty in reading a word, difficulty in isolated understanding, or typical reading achievement. Working memory and planning (when controlling attention, coding, fluency, and vocabulary) make a meaningful contribution to understanding what is being read but not word recognition. Findings of difficulty in planning have continued in adolescents who had difficulty understanding the reading even after controlling the accompanying ADHD and phonological processing ability. Although reading disorders are often accompanied by ADHD, these studies show that executive functioning difficulties may also occur in individuals without ADHD but reading-comprehension difficulties, and that the difficulties of strategic planning are closely related to the difficulties of understanding [58–60].
