Columnist and neuroscientist Roberto Lent introduces different conceptual models to explain reading, and suggests that new tools are available to improve dyslexic children’s performance

 

We usually think that reading is an ability of the human brain very related to speech, so that whoever is proficient in one, is also proficient in the other. It is not like that. All evidence indicates that speech is a biological property of humans, acquired over a long evolutionary period of time, that slowly ended up providing us with territories of the cerebral cortex exclusive to this function.

Reading, on the other hand, is an adaptation generated by the culture that human society has created, along a time period much shorter than that which allowed the emergence of speech. Brain areas that underlie reading are “lent” from other functions that would reside there, if the person does not – usually for social reasons – develop this ability. This is apparently the case of the illiterate, whose “reading areas” become dedicated to another aspect of complex perception: face recognition.

To speak, therefore, is biological. To read, however, is cultural. Almost all human beings speak and, when they are unable to do it, it is difficult to fix, since the causes are usually of biological nature. Many human beings, however, are unable to read, and the reasons are usually social. In both cases, there are exceptions that confirm the norm: people who do not speak due to social causes (emotional, for instance), and others who do not read because of biological impairments.

In this last group are the dyslexic children, who parents and teachers identify at the first attempts to stimulate them or to teach them how to read. These children show difficulties to learn fluent reading skills, despite the efforts to offer them abundant and frequent exposure to written materials, and independently of their social status. Because of the relative confusion between the weight of biological factors and that of social/cultural determination in the case of reading as compared to speech, it is common to think that dyslexics have something wrong in their brain areas dedicated to reading.

We will see below that it is not so, necessarily.

The map of brain regions that become activated by reading has been identified by different researchers with the help of functional magnetic resonance imaging. Among them is the French neuroscientist Stanislas Dehaene and his Portuguese and Brazilian collaborators. As in all complex cognitive functions, many brain regions increase their activity during reading. But what is the contribution of each one?

Dyslexic children have difficulty in reading with enough speed to catch the meaning. (Picture: Flickr/John Morgan - CC BY 2.0)

Dyslexic children have difficulty in reading with enough speed to catch the meaning. (Picture: Flickr/John Morgan – CC BY 2.0)

One of these regions became known as the visual word form area, a name that led to the belief that reading would have an important perceptual biological basis: a brain territory specialized in identifying the form of letters and words. Reading would be no more than a mechanism of perception of complex symbolic forms. Would dyslexia be caused by a deficit on that area, making the kid unable to recognize words as words, and differentiate them of similar, but meaningless, scribbles?

It was soon discovered that things were not so simple. The reading circuit included regions involved in attention, speed of perceptual processing, cognitive inhibition, working memory and error monitoring. Indeed, dyslexic children have also difficulties in performing these functions known as executive.

Two important consequences derived from this idea: a conceptual model about the neural basis of reading, and a tool (RAP, Reading Acceleration Program) designed to improve learning of reading abilities by kids (dyslexics or not). The conceptual model was developed by the group of investigators led by Bradley Schlaggar, from the University of Washington, in St. Louis, USA. And the tool to speed up reading was invented by Zvia Breznitz and collaborators at the University of Haifa, Israel.

The conceptual model: reading is not only word perception, it is a lot more. It depends on two networks of brain areas highly interactive with visual word perception regions, that maintain executive control of reading. The first area is called frontoparietal, responsible for focusing the reader’s attention on written cues (letters, words). The second network is known as cinguloopercular, in charge of keeping the goals alive (read until the end…), as well as monitoring and avoiding errors (do not skip letters or words…). In other words, it is not enough to identify them (the words…): it is necessary to recognize the spelling, imagine the pronunciation, understand the meaning, and on top of all, perform these functions under high-speed, left-to-right eye displacement (or in other directions, as is the case for Hebrew and Japanese), keeping in memory for a couple of seconds what came before, to finally understand the global meaning of what was read. Difficult!

Perhaps dyslexic children are fully capable of reading, but cannot do it at high speed and focused attention? Perhaps, then, it would be possible to teach them to accelerate this process?

A research group at the Cincinatti Children’s Hospital, Ohio, USA, led by Tzipi Horowitz-Kraus, decided to focus on these aims. They studied a group of dyslexic kids about 10 years old, and another of similar age, showing normal reading skills. Both groups were subjected to functional neuroimaging, at rest. Then, they were trained during 4 weeks with RAP. And finally, they underwent a new set of images. The researchers discovered that training increased activity of executive control regions, those that contribute to reading speed and attentional focusing.

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The two top images were acquired from dyslexic children, and the two at the bottom from kids capable of fluent reading. To the left, the connectivity within and between the hemispheres (L, left; R, right) during the first test. The right panels show the same connectivity after 4 weeks training with the reading acceleration program. The yellow color denotes low activity, orange depicts intermediate activity, and red shows high activity. The thickness of connection lines represents the connectivity strength. Notice that an increase of activity occurs at the executive control regions of dyslexics after training.

Not a miracle, nor a panacea. The program of reading acceleration consists of a bank of 1,500 sentences with words of frequent use in diverse languages. The training was performed through the internet, during 4 weeks, 5 days per week, 15-20 minutes per session. The researchers had remote access to the training and could record the progress of the kids, measuring the reading variables: time and speed, mainly. Comprehension was measured at the end using a very simple multiple-choice test about the content of the sentence read.

The main trick: as long as reading progressed (from left to right, in English), words disappeared at left, with a speed chosen and controlled by the experimenter. This forced the reader to be more attentive and speed up reading. Literally, it pushed the kids’ reading.

Results showed an improvement in reading and executive functions of dyslexic children, as well as of those capable of fluent reading.

These works allow some important conclusions. First: dyslexic kids do not have intelligence problems, they are as able as all other children. Second: they do not have deficits in visual perception and interpretation of abstract forms, as well. Third: there is a deficit in focusing visual attention and retaining information temporarily in memory, what results in reading slowness and consequently a deficit in comprehension. Lastly: there are tools being optimized, capable of accelerating reading in these kids by training, improving their performance.

Not bad to face a disorder of 5% children in all countries, different cultures, and different idioms!

 

Suggestions for Further Reading

S. Dehaene e colaboradores (2010) How learning to read changes the cortical networks for vision and language. Science, vol. 330, pp. 1359-1364.

Z. Breinitz e B. Bloch (2010) Reading acceleration program (RAP) [software], University of Haifa, Israel: Edmond J. Safra Brain Research Center for the Study of Learning Disabilities.

A.C. Vogel e colaboradores (2013) Functional network architecture of reading-related regions across development. Brain and Language, vol. 125, pp. 231-243.

T. Horowitz-Kraus e colaboradores (2015) Increased resting-state functional connectivity in the cíngulo-opercular cognitive-control network after intervention in children with Reading difficulties. PLoS ONE 10(7): e0133762.

About The Author

Roberto Lent

Rede CpE coordinator and Professor of Neuroscience at the Institute of Biomedical Sciences, Federal University of Rio de Janeiro (UFRJ). Publishes papers on brain development and brain plasticity and have wrote many science dissemination books on neuroscience for adults and children.

One Response

  1. ora exacta

    Am aflat aceasta pagina, dupa ce am cautat despre CONNECT: To read or not to read, that’s
    the question pe Google. Se pare ca informatia dvs e foarte valoroasa, mai
    ales ca am mai gasit aici si despre ora, ora exacta, lucruri
    interesante si folositoare. Mult succes in continuare!

    Reply

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