Reading networks in children with dyslexia compared to children with ocular motility disturbances revealed by fMRI
Front. Hum. Neurosci.. 2014-11-19; 8:
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1. Front Hum Neurosci. 2014 Nov 19;8:936. doi: 10.3389/fnhum.2014.00936. eCollection
Reading networks in children with dyslexia compared to children with ocular
motility disturbances revealed by fMRI.
Saralegui I(1), Ontañón JM(1), Fernandez-Ruanova B(2), Garcia-Zapirain B(3),
Basterra A(3), Sanz-Arigita EJ(4).
(1)Department of Neuroradiology, Osatek, Galdakao-Usansolo Hospital Galdakao,
(2)Research Department, Osatek Bilbao, Spain.
(3)DeustoTECH Life (eVIDA), University of Deusto Bilbao, Spain.
(4)CITA-Alzheimer Foundation Donostia, Spain ; Radiology and Image Analysis
Centre, VU Medical Centre Amsterdam, Netherlands.
Key PointsDyslexia is a neurological disorder with a genetic origin, but the
underlying biological and cognitive causes are still being investigated.This
study compares the brain activation pattern while reading in Spanish, a
semitransparent language, in three groups of children: typically developing
readers, dyslexic readers and readers with functional monocular vision.Based on
our results Dyslexia would be a neurological disorder not related to vision
impairments and would require a multidisciplinary treatment based on improving
phonological awareness and language development. Developmental dyslexia is a
neurological disorder the underlying biological and cognitive causes of which are
still being investigated, a key point, because the findings will determine the
best therapeutic approach to use. Using functional magnetic resonance imaging, we
studied the brain activation pattern while reading in the language-related
cortical areas from the two reading routes, phonological and orthographic, and
the strength of their association with reading scores in 66 Spanish-speaking
children aged 9-12 years divided into three groups: typically developing readers
(controls), dyslexic readers and readers with monocular vision due to ocular
motility disorders but with normal reading development, to assess whether (or
not) the neuronal network for reading in children with dyslexia has similarities
with that in children with impaired binocular vision due to ocular motility
disorders. We found that Spanish-speaking children with dyslexia have a brain
circuit for reading that differs from that in children with monocular vision.
Individuals with dyslexia tend to hypoactivate some of the language-related areas
in the left hemisphere engaged by the phonological route, especially the visual
word form area and left Wernicke’s area, and try to compensate this deficit by
activating language-related areas related to the orthographic route, such as the
anterior part of the visual word form area and the posterior part of both middle
temporal gyri. That is, they seem to compensate for impairment in the
phonological route through orthographic routes of both hemispheres. Our results
suggest that ocular motility disturbances do not play a causal role in dyslexia.
Dyslexia seems to be a neurological disorder that is unrelated to vision
impairments and requires early recognition and multidisciplinary treatment, based
on improving phonological awareness and language development, to achieve the best