Visual Training Helps Improve Reading in Dyslexic Children with Abnormal Crowding

Abstract

Aims: To evaluate the effectiveness of visual training aimed at improving the visual function in dyslexic children suffering from increased crowding. Study Design: Single-masked crossover pilot study. Place and Duration of Study: University of Turin and the Gradenigo Hospital, Department of Ophthalmology, Turin, between March and November 2014. Methodology: 14 reading-impaired children (8-11 years) with increased paracentral crowding underwent a visual training devised to improve reading fluency by reducing lateral masking. Patients were asked to recognize trigrams of letters with different inter-letter spacing displayed at variable eccentricities on both sides of the fixation point (trigram training). Since any visual task chosen as a placebo could show some rehabilitative effect, placebo training was replaced by a period of reading practice, when reading exercises were recommended to be done at home. Results: After two weeks of training, in the recruited sample reading rate for words increased from 1.88 syl/sec (SD:±0.74) to 2.19 syl/sec (±0.86). Reading rate for non-words improved from 1.13 (±0.39) syl/sec to 1.28 (±0.42) syl/sec. No significant improvement was found after the period of reading practice both at words and non-words. Analysis of variance showed a significant reading exercise x trigram training effect both for words (P= .0004) and non-words (P= .0001) in the recruited sample of disabled readers. To confirm the ameliorative effect of training (not being involved a placebo), a second, smaller sample has been administered the reading practice before the treatment. In this second group no substantial change in reading fluency was found after two weeks of reading practice, whereas after the trigram training reading rate improved by 11.8% at words and 29% at non-words despite, probably due to the small size of the second sample, results did not reach statistical significance. Conclusion: Trigram visuoperceptive training demonstrated to be effective in improving reading rate in dyslexic children suffering from reinforced crowding. The ameliorative effect of the rehabilitation is found to be sharper in patients showing abnormal crowding compared to the non-classified dyslexics trained in a previous study. Interdisciplinary rehabilitative approach of developmental dyslexia should therefore consider also visuoperceptive rehabilitation aimed at normalizing lateral masking.