Background and Purpose: Since the beginning of the identification of dyslexia problems, most research in this field has been based on medical and deficit-oriented approaches, all of which emphasize mostly on the existence of defects and disorders. However, over the past few decades, several studies have shown that dyslexia does not necessarily mean impairment but it is a different form of mental processing that is rooted in a diverse neurological functioning. Some findings specifically propose that individuals with dyslexia have different and even some superior visual-spatial talents. However, the limited experimental evidence has yielded conflicting results. The aim of the present study was to investigate this issue by focusing on the research on the differences between visual-spatial processing and the existence/lack of such capabilities in individuals with dyslexia.
Method: This research is a kind of descriptive-critical review study. Extensive searches were performed in Iranian and international databases, including SID, Magiran, Ensani, Civilica, Web of Science, ERIC, EBSCO, ScienceDirect, PubMed, Psych INFO and Google Scholar, using the following keywords: dyslexia, reading disorder, reading disability, visual-spatial perception, visual-spatial ability, creativity in dyslexia, nonverbal skills, neurodiversity, and difference-oriented approach. After preliminary study of 124 papers, the unrelated studies were excluded, and 28 papers entered the analysis stage. Data were analyzed by PRISMA model.
Results: Examination of selected papers showed that in 18 tests (20.5%) the performance of participants with dyslexia was higher than their non-dyslexia counterparts. In 36 tests (40.9%) the difference in visual-spatial performance between dyslexia and non-dyslexia group was not significant, and the performance of dyslexic group was equivalent to that of non-dyslexic group. Results of 34 tests (38.6%) showed that dyslexic group had a lower performance compared to the non-dyslexic participants.
Conclusion: The findings show that the performance of the dyslexics was better in the overall understanding of the whole image, holistic processing, and representation of complex and impossible figures, and they showed a faster reaction time. But there is little evidence to support the existence of visual-spatial talents in all the visual perceptual areas among individuals with dyslexia. Finally, with various research limitations such as the selection of samples with different developmental and training levels and from various age groups, the different methodologies, and the assessment tools used in each study, achieving a more accurate profile of the cognitive strengths and weaknesses of individuals with dyslexia requires further research. |