پديد آورندگان :
نبي زاده نودهي، رويا دانشگاه آزاد اسلامي واحد علوم و تحقيقات تهران , برجعلي، احمد دانشگاه علامه طباطبايي تهران - گروه روانشناسي باليني , استكي، مهناز دانشگاه آزاد اسلامي واحد تهران مركز - گروه روانشناسي , فرخي، نورعلي دانشگاه علامه طباطبايي تهران - گروه سنجش و اندازه گيري
چكيده لاتين :
Background & Objectives: Children with dyslexia have long been the focus of psychological and educational studies. Dyslexia is divided into
5 subgroups. In this study, two main types, visual and auditory dyslexia, were examined. Some experts believe that visual and auditory types of
dyslexia could be distinguished based on differences between the verbal and non–verbal index of the Wechsler Intelligence Scale, which indicates
left and hemisphere performances, respectively. According to some researchers, most childhood neurological disorders, like dyslexia, are due to
the lack of brain development at the same rate and imbalance in electrical activities between its different areas, especially in the right and left
hemispheres. Executive functions are controlled in the prefrontal lobe of the cortex; they drive how a child will think, plan, control impulses,
establish goals and regulate behavior, and engage in other high–level activities. Defect in executive functions also results from the fact that
important parts of the brain might not have been properly developed; by training the two hemispheres, the imbalance between the hemispheres
could be fixed. Therefore, the current study aimed to investigate the effect of two–hemisphere training on the executive functions of planning
and response inhibition of auditory dyslexic students.
Methods: We implemented a convenience sampling method for selecting the study samples. The statistical population of the present study
included 90 students from the waiting list of two educational centers for learning disabilities in Tehran City, Iran, in the 2016–2017 academic
year. Using a quasi–experimental and pretest–posttest design with a control group, 59 students in the second and third grades of primary school
were selected according to the research inclusion criteria. Based on the differences between the scores of verbal comprehension and perceptual
reasoning in the fourth edition of the Wechsler Intelligence Scale for Children (Wechsler, 2003), 20 students were identified with auditory
dyslexia. Then, from auditory dyslexic students, randomly and by drawing lots, half were included in experimental and half in control groups.
After obtaining consent from the parents of children, the experimental group received two–hemisphere training after performing pretests;
however, the control group received no training. After conducting 16 sessions of two–hemisphere training, posttests were performed in the study
participants. To observe research ethics on the non–exclusion of a group from training, the controls were also trained after the implementation
of the posttests. The research screening tools consisted of the Clock Drawing Test (Tuokko, 1995); the test’s reliability was obtained as 0.91.
Moreover, the Raven Progressive Matrices test for children (Raven, 1956) was used, with the reliability of 0.89–0.95. Other research tools
included the Reading and Dyslexia Test (NEMA; Moradi & Kormmi Nouri, 2008), and the Wechsler Intelligence Scale, the fourth edition; the
reliability of this version for FSIQ was reported to be 0.97. The computer version of the Tower of London Test (Shallice, 1982) was used in the
present study to measure the executive function of planning and organization. The reliability of The Tower of London Test was reported to be
0.79. The Stroop Color and Word Test (SCWT) (Stroop, 1935) was also applied to measure response inhibition capability. The reliability of this
inventory was reported as 0.768 for the congruent colored words and 0.904 for incongruent colored words. The obtained data were analyzed in
SPSS by Multivariate Analysis of Covariance (MANCOVA) (p<0.05).
Results: After adjusting the test effect on the experimental group, in the variable components of planning, including test time (p=0.027), delay
time (p=0.038), error (p=0.036) and score (p=0.018); and in the variable components of response inhibition include, consistent response
(p=0.017), matching response time (p=0.019), inconsistent response (p=0.004), inconsistent response time (p=0.009) and Interference scores
(p=0.013) showed a significant difference.
Conclusion: The obtained mean (SD) scores suggested that in all components of the two variables, the performance of planning and response
inhibition after the intervention was significantly different in the pretest and posttest of the experimental group. However, these differences were
not significant in the controls. The collected results indicated that two hemisphere training was effective in improving the performance of
planning and response inhibition of the investigated auditory dyslexic students. It is suggested that, along with other therapeutic methods, two
hemisphere training be implemented to increase the academic and cognitive efficiency of dyslexic students and children with other
neurodevelopmental disorders.
