Magnocellular Based Visual Motion Training Improves Reading in Persian

Leila Ebrahimi,Ali Khatibi,John Stein,Hamidreza Pouretemad

doi:10.1038/s41598-018-37753-7

Abstract

The visual magnocellular system is thought to play a crucial role in learning to read. Here therefore, we examined whether magnocellular based training could improve reading in children with visual reading problems. The participants were 24 male primary school students aged between 9–11 (Mean = 9.76, SD = 0.59) with specific reading difficulty. Experimental and control groups were matched for age, sex, educational level, IQ, reading abilities (measured by APRA), magnocellular performance as assessed by a random dot kinematogram (RDK) paradigm and recordings of their saccadic eye movements. The experimental group received twelve magnocellular based visual motion training sessions, twice a week over 6 weeks. During the same period, the control group played a video game with the help of a practitioner. All measures were made just prior to the training and were repeated at the 6th, 12th training session and one month later. The experimental group showed significant improvements in magnocellular function, visual errors and reading accuracy during the course of intervention. Follow-up assessment confirmed that these effects persisted one month later. Impaired magnocellular functioning appeared to be an important cause of poor reading in Persian. Hence magnocellular based training could help many children with specific reading difficulties. Also testing magnocellular function could be used as screening tool for detecting dyslexia before a child begins to fail at school.

Highlights

The visual magnocellular pathway originates in the magnocellular ganglion cells in the retina and projects via the magnocellular layers of the Lateral Geniculate Nucleus (LGN) to the primary visual cortex (V1) situated at the back of the occipital lobe[6]
There were no significant differences between the two groups at the first session, but the dyslexics in the experimental group had lower thresholds by the sixth session (t(22) = −2.64, p = 0.015), twelfth session (t(22) = −3.63, p = 0.001) and at the 1 month follow-up (t(22) = −2.250, p = 0.035) compared to the control group
Pairwise comparisons within the experimental group, showed a significant reduction in random dot kinematogram (RDK) threshold from first session to sixth session, twelfth session and at follow-up, but there were no significant changes for the control group (p > 0.05) (Fig. 1)

Summary

Introduction

The visual magnocellular pathway originates in the magnocellular ganglion cells in the retina and projects via the magnocellular layers of the Lateral Geniculate Nucleus (LGN) to the primary visual cortex (V1) situated at the back of the occipital lobe[6]. The dorsal one of these is often called the ‘where’ stream; it receives 90% of its visual input from the magnocellular system and projects to the visual motion sensitive area (V5/MT) and thence to the Posterior Parietal Cortex (PPC) This pathway mediates motion perception and object localization[7] and it plays a major role in directing visual attention and in eye movement control[8]. Lawton (2016) and Lawton and Shelley-Tremblay (2017) investigated the efficacy of figure-ground Discrimination Training on reading ability in individuals with dyslexia[30,31] This task activates the magnocellular pathway selectively and it enhanced their reading fluency; this was accompanied by improvements in their visual timing deficits, attention, phonological processing and working memory. The results indicated that active, not sham stimulation, improved reading speed and fluency[33]

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Discussion

Conclusion