The Effectiveness of Teaching Cognitive Abilities Based on the Cattel-Horn-Carroll Approach on Working Memory of Male Students with Specific Learning Disorder, Dyslexia

Specific learning disorder refers to people's inability to interpret what they see or hear or relate input information from different parts of the brain to one another. It is the most common neurodevelopmental disorder and the basis of cognitive disorders in children. Its three specifiers include dyslexia, dysgraphia, and dyscalculia. Dyslexia, one of the most common childhood disorders, creates many educational problems for students. Among students with specific learning disabilities, the group with reading difficulties has a large number. The nature of the problem lies in processing speed and working memory and the impaired relationship between working memory and dyslexia. This study evaluated the effectiveness of education cognitive abilities based on the Cattell–Horn–Carroll approach to working memory of students with special learning disorders with dyslexia.

The research method was quasi–experimental with a pretest–posttest design and a control group. The statistical population included third–grade elementary school students with special learning disorders studying in Tehran City, Iran, in the academic year 2017–2018. They were studying in educational and training centers for rehabilitation problems specific to the Special Education Organization. They were diagnosed as children with learning disabilities. Among them, 30 students were selected by convenience sampling and randomly assigned to experimental and control groups (15 students in each group). The inclusion criteria were as follows: being a boy, lacking a mental illness and psychiatric record, studying in the third grade of elementary school, and having IQ over 90. They were diagnosed with dyslexia by exceptional centers, not having comorbid disorders, including language disorders, attention–deficit/hyperactivity disorder, and no emotional problems or sensory, motor, visual, or auditory impairment. These criteria were determined by referring to students' files and observations in the initial sessions. Non–participation in all intervention sessions was considered the exclusion criterion. The instrument used was Wechsler Intelligence Scale for Children Fourth Edition (WISC–4) (Wechsler, 2003). The working memory index of the above tool was used to measure the working memory. Both control and experimental groups performed before and after the intervention and at the follow–up phase. Subjects in the experimental group received cognitive abilities training, and the control group received no special training. Interventions consisted of cognitive abilities training, based on training based on the Cattell–Horn–Carroll approach for the experimental group in 30 sessions, three sessions per week for 3 months, and based on a pre–determined program. In the next step, the posttest was performed, then the follow–up was tested after one month. Data analysis was performed by repeated measures analysis using SPSS version 16, and the significance level was set at 0.01.

The results showed a significant difference in dependent variables, including "number capacity" (p=0.001), "number–letter sequence" (p=0.001), and "calculations" (p=0.005) between the experimental and control groups. The tests of intra–subject effects related to the examination of dependent variables in the three stages of pretest, posttest, and follow–up also determined a significant difference in the amount of number capacity (p=0.001), number–letter sequence (p=0.001) and calculations (p=0.001) between the three stages of measurement. The effect size was 0.31 for the number capacity, 0.21 for the letter–number sequence, and 0.44 for the calculations.

The study's results indicate the effectiveness of interventions related to training cognitive abilities in improving the working memory function of students with dyslexia. So, this program can be considered a solution for educators with specific learning disabilities. Keywords: Students with special learning disabilities, Dyslexia, Working memory, Cognitive abilities, Cattell–Horn–Carroll approach.