Neurovisual training (TRIGRAM) in young patients with visual-perceptive dyslexia

Abstract

Dyslexia is a language-based learning disability. Although this condition is characterized by anatomical malformation of the brain,
it seems that the typical reading pattern of dyslexic may be also related to more complex sensory deficits. Among them, visualperceptive
deficits have been described in a subtype of dyslexia, called visual-perceptive dyslexia. The distinctive feature of a patient
suffering from visual-perceptive dyslexia form is marked by effortlessly recognize the characteristics of each individual stimulus.
The Tetra protocol is a visual-perceptual evaluation protocol that was introduced for the diagnostic phase and the rehabilitation of
visual-perceptive dyslexia. The diagnostic tests include: the eidomorphometry test, designed to evaluate the perception of spatial
relationships; the contrast sensitivity threshold test, especially at low spatial frequencies; and the REPORT TEST words, to assess the
speed and the reading efficiency. In addition, the rehabilitation phase is carried out with the visual neuro-enhancement program
TRIGRAM, a visual training proposal designed to reduce the lateral masking phenomenon in visual-perceptive dyslexic.
Thus, in this study we used the diagnostic tests of TETRA® Protocol to determine presence of visual-perceptual abnormalities in
children with dyslexia. Proven time the presence of these visual-perceptual alterations, the patients were also subjected to the
rehabilitation sessions of TRIGRAM, in order to investigate whether this visual training may improve the pattern of reading. At the
end of the program (t1) and after three months (t2), the same subjects underwent the same diagnostic tests of TETRA® Protocol to
evaluate and confirm the results obtained during rehabilitation program.
The results showed a significant increase in contrast sensitivity at low and high spatial frequencies. Moreover, the same
improvements in the visual system's ability to discriminate the contours of an object within the field of view, have been maintained
three months after the end of treatment. We also observed a significant improvement in the perception of spatial relationships, with
reduction of SRA value.
In conclusion, this study demonstrates that the visual rehabilitation training (TRIGRAM) is able to improve the perception of
spatial relationships, and increase contrast sensitivity in young patients affected by "visual dyslexia". Nonetheless, these data need to
be confirmed in larger cohort of subjects in order to establish whether these effects can also increase lexical ability (increased reading
speed and reduce errors during the lexical task).