Ibone Saralegui, the author of the thesis Análisis mediante resonancia magnética funcional de las redes neuronales para la lectura en niños con dislexia (Analysis using functional magnetic resonance imaging of the neuronal networks for reading in children with dyslexia), has pointed out that there is no cure for dyslexia, but correct, early treatment can considerably improve the reading and comprehension capacity of those affected by this disorder. Yet the percentage of dyslexics is much higher among speakers of opaque languages, such as English and French, according to this study.
Dyslexia is a primarily neurological disorder, not a visual one
According to a study by the UPV/EHU-University of the Basque Country, alterations in ocular motility do not influence dyslexia directly
First publication date: 03/09/2015
"Dyslexia is the difficulty displayed by some children in acquiring reading skills and this difficulty prevents them from achieving, through normal means, learning relating to writing, irrespective of their other cognitive skills such as intelligence, reasoning or memory," as the neuroradiologist Ibone Saralegui explained in her thesis. Historically, dyslexia has been associated with problems of visual perception, but this association has been refuted by the most recent pieces of research.
Saralegi is the author of one of these pieces of research; it was conducted together with the ophthalmologist Ricardo Martínez; fMRI (functional Magnetic Resonance Imaging) was used to assess the neuronal network linked to reading in children with dyslexia and who had previously not undergone any treatment. The results of the study show that readers with dyslexia appear to have a neuronal network for reading which is different from that of normal readers and from those with ocular motility (mobility) disorders.
The researcher highlights the fact that dyslexia does not have a single cause and that probably various factors are involved in its onset. "In any case, one of the main causes is an alteration in children's phonological route for reading, which greatly influences the therapy that has to be applied to them. Visual and auditory therapies, for example, are not appropriate for treating these children," said the author of the thesis. According to Saralegi, "there is no cure for dyslexia. Many parents go and see the ophthalmologist or speech therapist thinking that after a good course of treatment their child is going to stop being dyslexic. But a child (or adult) is always dyslexic. However, with the help of early appropriate treatment, their reading skill and comprehension capacity can improve significantly."
Opaque languages and transparent languages.
The study, which is the focus of the thesis, was conducted with Spanish-speaking children, "although the conclusions could be extrapolated to Basque-speaking children," according to Saralegi, "since Basque and Spanish have a very similar level of semi-transparency. Transparent languages are the ones in which the grapheme coincides with the phoneme, in other words, in those in which one letter tends to correspond to one sound. In opaque languages (e.g. English, French), by contrast, one grapheme (the letter "A", for example) can be pronounced in different ways (/a/, /ei/). In reading, the first crucial step is this linking of phonemes with graphemes".
So opaque languages have an added problem: several phonemes have to be learnt for the same grapheme. "That is why the percentage of dyslexic children is almost double in these languages. In transparent and semi-transparent languages the incidence of dyslexia is lower and it appears later, although the comprehension problem persists," said the researcher.
Additional information:
Ibone Saralegui-Prieto, the author of the thesis Análisis mediante resonancia magnética funcional de las redes neuronales para la lectura en niños con dislexia (Analysis using functional magnetic resonance imaging of the neuronal networks for reading in children with dyslexia), is a UPV/EHU graduate in medicine and surgery and a neuroradiologist. She works for OSATEK at the Hospital of Galdakao. The research was carried out in the 3T team at this hospital with the collaboration of the paediatric ophthalmology section of the University Hospital of Cruces and deustoTECH Life (eVIDA) of the University of Deusto.
Her thesis was supervised by Dr Juan Carlos García-Moncó, head of the neurology service of the Hospital of Galdakao, and Dr Pedro Grandes-Moreno, Professor of the UPV/EHU's Department of Neurosciences.
Bibliographical references:
- Differences in effective connectivity between children with dyslexia, monocular vision and typically developing readers: A DTI study. B. Garcia-Zapiraina, Y. Garcia-Chimenoa, I. Saralegui, B. Fernandez-Ruanova, R. Martinez. Biomedical Signal Processing and Control. 2016; 23: 19-27
- Reading networks in children with dyslexia compared to children with ocular motility disturbances revealed by fMRI. I. Saralegui, JM Ontañón, B. Fernández-Ruanova, B. García-Zapirain, A. Basterra, E. Sanz-Arigita. Front Hum Neurosci. 2014; 8 (936): 1-15.
- Automatic classification of dyslexic children by applying Machine Learning to fMRI images. Y. García Chimeno, B. Garcia-Zapirain, I. Saralegui, B. Fernández-Ruanova. Bio-Med Mater Eng. 2014; 24(6): 2995-3002.