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Aims: To investigate visuoperceptive abnormalities in adult dyslexics with the TETRA Analyzer™, and to compare the results with those obtained with normal adult readers.
Study Design: Epidemiological study.
Place and Duration of Study: Service of Neuro-Ophthalmology, University of Turin, Italy, between April 2016 and October 2017.
Methodology: Ocular dominance, spatial relationship perception, and interocular visual input have been tested in 25 adolescent and adult dyslexic readers (age 11-34 years) with the TETRA Analyzer™. The TETRA Analyzer™ is a set of 4 exams devised to evaluate ocular dominance (Domitest M), spatial relationship perception (Eidomorphometry), interocular sensory pattern (Domitest S), and their effect of the reading performance (Reading Performance Test, REPORT). Results have been compared with the normative data of a sample of adult subjects (“mature readers”) gathered in a previous investigation.
Results: Compared to mature readers, a higher proportion of adult dyslexics showed dominance instability (20% vs 4%). Average spatial relationship anisotropy was up to threefold higher in adult dyslexics (3.54% vs 1.32% in mature readers). The distribution of the interocular inhibition was bimodal, resembling that of immature readers (children). The reading rate of non words was strongly affected by the inter-letter spacing (R2=0.50, P=.01), in support of an involvement of these alterations in affecting the lexical function.
Conclusion: Defective visuoperceptive functions can play a role not only in children but even in adult dyslexic. The resemblance of dominance, spatial relationship perception and especially interocular inhibitory pattern of adult dyslexics and immature readers may be the sign that a stunt or delay of the normal development of these visuoperceptive functions takes place in a subpopulation of dyslexic subjects.