Dyslexia, eyes, light and hype

This week a story on dyslexia, my main research interest, has dominated the media, and I could not ignore it. Dyslexia is a specific difficulty in learning to read experienced by about 5-10% children in the UK. The causes and mechanisms leading to dyslexia are yet to be made clear and an effective universal treatment is not available. Every now and then, as it is often the case for childhood disorders, a miraculous cure is proposed ranging from videogames, to  coloured lenses or even electric therapy.

These announcements usually follow small sized studies reporting small effects but which regularly make big headlines. Rarely the results are independently replicated and confirmed in follow-up studies. And even if they did, the negative results would not make it in the news. Providing any findings describe a genuine effect and a particular treatment could have beneficial effects for some individuals, it is very unlikely that a universal remedy could resolve dyslexia given it varies along a spectrum and has individuals with the condition show differences in their patterns of difficulties.

But let’s see what the latest story is about. This time it is not about cure but cause. Most of the news outlets have headlines declaring that the “real cause” of dyslexia is in the eye (e.g. The cause of dyslexia lies in the eyes for The Sun or in eye spots confusing the brain for the BBC) with a few articles also alluding to a cure (e.g. Dyslexia treatment potentially discovered in The Independent). They refer to a paper published in the Proceeding of the Royal Society B journal. The authors, Albert Le Floch and Guy Ropars, are based at the University of Rennes 1, France, in the Physics Department and have no previous track record in the field of dyslexia.

Briefly, the study analysed 60 students divided in two groups defined as normo-readers and dyslexics. The authors describe the “dyslexic” group to have a reduced ocular dominance which they suggest to be linked to a reduced structural asymmetry in the retina when compared to the normo-readers. The authors conclude their article by stating that the “lack of asymmetry might be the biological and anatomical basis of reading and spelling disabilities in people with a normal ocular status but with dyslexia, perturbing the connectivity of different regions in the brain and inducing the observed common visual and phonological difficulties. Our results suggest early anatomical diagnosis of dyslexia in young children and possible compensation for their potential lack of asymmetry, especially during the critical period.”

The study has been openly criticised by scientists working in the field of dyslexia who are puzzled as to how it managed to get published in a respectable journal and pass the peer-review process. For an extensive critique see this blog by Prof Mark Seidenberg at Columbia University that received supports by many other scientists who shared it on Twitter. Some of the key problems with the study are a very small sample size which could easily lead to biased results, lack of details on how the “dyslexia” group was identified and the over-interpretation of the results by the authors.

So any exaggerations in the headlines seem to build on already over-interpreted results by the authors themselves.

As we have seen many times in the past, quite often the headlines are not just the product of poor journalism, but the direct results of hyped press releases which involve the contribution of the scientists themselves (e.g. see the claim of a link between c-sections and autism). In this case, I was not able to identify a press release by the University of Rennes and most news outlets quoted their source as a press release by AFP which I could not find either. However, while I do not speak French and my judgement is based on Google Translator, the author themselves appear to declare in this interview, with demonstrative videos, “ to have understood the mechanisms at the basis of dyslexia and found a way to correct it” using particular light conditions. This reinforces the message that, while undoubtedly the headlines offering a definitive diagnosis and hope for a cure are sensationalist, once again the scientists themselves should avoid spreading irresponsible claims that have the potential to ultimately damage people with dyslexia.

Original paper: “Left–right asymmetry of the Maxwell spot centroids in adults without and with dyslexia” by Albert Le Floch, Guy Ropars in Proceedings of the Royal Society B, 2017

DOI: 10.1098/rspb.2017.1380.