Friday, November 22, 2019
US flag

Green filter helps dyslexic students read faster

Reading, one of the most difficult activities for children with dyslexia, can be improved by the use of green filters.


Either glasses or technology can provide useful color-contrast filters (Vision Help blog/Leonard Press, OD)

A study described in an article by Brazilian and French researchers reports increased reading speed for 9- and 10-year-old volunteers with dyslexia who used green filters. The filters had no effect on age-matched children without dyslexia.

Colored filters for the treatment of learning disabilities were first patented in 1983. They were also designed for use by children with autism and attention deficit hyperactivity disorder (ADHD).

“However, studies of their efficacy were methodologically flawed. We used a highly rigorous methodology for the first time,” said Milena Razuk, first author of the article, published in the journal Research in Developmental Disabilities.

The filters are not widely used in Brazil owing to a lack of research, although they have been adopted in some countries, such as France.

Razuk, who completed her PhD in April at Cruzeiro do Sul University (São Paulo, Brazil), performed the experiment while in France on a research internship at Paris Diderot University (Paris 7), with support from the Sao Paulo Research Foundation, or FAPESP.

Eighteen children with dyslexia and 18 without dyslexia were selected for the study at Robert Debré Hospital in Paris. The researchers decided to use yellow and green filters in the experiment.

“Twelve colors are available, but we chose two because a very long test would be too demanding for the volunteers,” said José Angelo Barela, a professor at São Paulo State University’s Rio Claro Bioscience Institute (IBRC-UNESP) in Brazil and principal investigator for the project.

Faster Reading

All 36 children were asked to read passages from children’s books suited to their reading age. The texts were displayed on a computer screen with a yellow filter, a green filter, and no filter.

Their eye movements were recorded with the Mobile EyeBrain Tracker®, a French eye-tracking device certified for medical purposes, consisting of goggles fitted with cameras that record the movements of each eye independently via infrared light signals.

“A child with dyslexia has to fix his or her gaze on the words for a longer time to understand a text. Reading speed is slower as a result,” Barela told.

While the filters did not affect reading speed for the children without dyslexia, the eye-tracking device detected a statistically significant difference for children with dyslexia, who read fastest with the green filter, fixing their gaze on groups of words for 500 thousandths of a second, compared with 600 thousandths of a second using the yellow filter or no filter. The fixation period with or without filters was 400 thousandths of a second for children without dyslexia.

The authors of the study stress that they did not evaluate whether the use of a green filter improved comprehension of what was read and that further research is needed to explore this dimension.

Dyslexia is poorly understood

The causes of dyslexia are unknown. In addition to reading difficulties, other deficits have been found to be associated with the disorder, including impaired sensorimotor integration. “It’s as if some source of noise disturbs the brain’s communication with the rest of the body,” Razuk said.

Extensive testing has shown that neither impaired eyesight nor intellectual deficiency is part of the condition. “IQ must be normal or above average for dyslexia to be diagnosed,” noted the FAPESP-supported researcher.

In the article, the authors of the study say the improvement in reading time with the green filter might be due to changes in the visual stimuli available for central nervous system processing.

Other studies have suggested that colored filters may reduce cortical hyperexcitability in the brain, which may be greater in dyslexic people, thereby attenuating contrasts in visual stimuli and hence improving reading performance.

This suggestion was reinforced by a 2015 study in which functional magnetic resonance imaging (fMRI) showed significant activation of the cerebral cortex during reading with colored filters (mostly blue in this case) compared with reading without filters. The authors hypothesized that the filters reduced visual stress and distortion, enhancing visual processing and reading performance.

The next step for the group at IBRC-UNESP will be to use fMRI scans to analyze the brain activity of dyslexic children while reading. Barela has purchased an MRI machine with funding from Brazil’s National Council for Scientific & Technological Development (CNPq).

Paul Katula is the executive editor of the Voxitatis Research Foundation, which publishes this blog. For more information, see the About page.

Recent posts

Girls’ volleyball champs in Illinois

We congratulate the Illinois state champions in girls' volleyball: Newark, St Teresa, Sterling, & Benet Academy.

A weekend of ‘band geeks’ across America

The musical Band Geeks was in performance at a MD high school, just as marching bands from across America named a national champion.

2 dead, 3 wounded in Calif. school shooting

Another school shooting has resulted in the death of 2 California high school students. The suspect shot himself and is in custody.

Mercury makes a transit; next in 2032

A transit of Mercury occurred today and was visible from the US, provided you had sunny skies. It was one of longest possible transits.

On the Naperville BWW racist incident

A racist incident at a Naperville, IL, sports bar indicates that the threads of racism are strong, perhaps as strong as ever.

IL bill could excuse absences to vote

A proposed law in IL could give students up to two hours during the school day so they could vote in the upcoming election.

Loan forgiveness gains some bipartisan support

One Republican from GA, who used to work under Betsy DeVos at the US Education Dept, offers a plan to forgive some student loan debt.

A band teacher is IL Teacher of the Year

IL named a band teacher the 2020 Teacher of the Year on Oct. 19. He individualizes music instruction and shares his work with 1000s.

‘Little Shop of Horrors’ bookends Halloween

Several high schools have decided to add a little spook to their musical stages in this season of Halloween. Music makes it happen.

New IL law ensures inclusion of LGBTQ+

A law will take effect next school year in IL that will require students to study LGBTQ history as part of the social studies curriculum.

MoCo doubles down on summer learning loss

Research is at least equivocal about summer learning loss, but maybe there's something to a new plan in Montgomery County, Md.