Middle Eastern Journal of Disability Studies

Abstract
Background and objective: Nonverbal learning disability as deficit in nonverbal information processing is associated with deficits in the executive functions. Children with nonverbal learning disabilities have deficits in visual-spatial perception, memory, motor-visual coordination, spatial precision, orientation skill. The weak performance of children with nonverbal learning disabilities in the executive functions result in academic problems. Such children have many problems in mathematics calculation, copying texts, writing texts and comprehension. The current study was conducted to study the effect of strengthening executive functions on academic achievement in children with nonverbal learning disability.
Methods: The statistical population of this study consisted of all students with nonverbal learning disabilities under the auspices of Learning Disorders Center of Shirvan-Iran in 2015. A total of 30 participants were recruited from among the children with nonverbal disability from primary school in second grade to fifth grade. The research instrument was Lotf Aabadi ʼ reading test, a researcher made writing test and Mathematical Standard Learning Ability Recognition Test. The participants were examined by clinical psychologist of the Learning Disorders Center and were judged to meet the criteria for learning disabilities through interview according to the third edition Wechsler intelligence scale. It was decided that those who scored 10 marks away from verbal and practical intelligence quotient should be diagnosed as students with nonverbal learning disability. The participants were assigned to experimental and control groups. Every participant in the experimental group was matched with a peer in the control group in terms of age and gender. The control group received only the usual school training while the experimental group received routine training and in addition to tasks of coding, trial making, verbal and visual memory for strengthening executive functions. The exercises were held individually in 12 sessions of 45 minutes. These exercises are to improve verbal memory, visual memory, visual - spatial coordination, sequencing motor skills, visual pursuit and attention. Analysis of covariance (ANCOVA) was used to analyze the data. 
Results: The effect of pretest differences via analysis of variance was controlled. There were significant differences in the posttest scores of the experimental and control groups on reading, writing and mathematics (p<0.001). The effect sizes of strengthening executive functions method were 0.62, 0.79 and 0.49 for improving of the reading, mathematics and writing respectively. According to effect sizes, it can conclude that strengthening executive functions is more effective for improving mathematics calculation.
Conclusion: The strengthening of executive functions could improve speed and correction in reading of the words, writing and spelling of the words and mathematics calculation. Trial making tasks strengthen psychomotor speed, abstraction, flexibility, ability for execution and correction of planning; coding tasks reinforce speed of information processing, perceptual organization processes and speed performance; tasks of verbal and visual memory strengthen attention, motor-visual coordination and memory. It can be stated that strengthening executive functions are beneficial to the academic achievement of students with nonverbal learning disabilities.