Understanding and treating reading disorders

Central to the activities of the Reading Program was to apply our models of reading and learning to read to understanding the basis of different kinds of reading and spelling disorders, and developing and testing targeted treatments. One example of the application of this theory-driven approach was the identification of a new form of developmental dyslexia in English: letter position dyslexia. Our models specify that successful word reading involves not only identifying each letter within the word but must also identify their correct position. Otherwise, a reader will have no way of differentiating between the words pat, tap, and apt, for example. While this process is clearly important, little research had explored how it operates, or whether there is variation in how well it is acquired. We developed a targeted test of letter position processing, which required children to read anagram words such as slime/smile, nerve/never and pirates/parties. Use of this test identified children who struggled specifically with this aspect of reading, even though they performed within normal range on all other measures, which we published in the prominent journal, Neuropsychologia (Kohnen, Nickels, Castles, Friedmann, & McArthur, 2012). Identification of this profile stimulated new research directions examining the underlying causes of this difficulty and determining optimal treatment methods.

We were also active in applying rigorous experimental methods to testing the veracity of proposed cures or treatments for dyslexia. One notable example of this is the Dyslexie font. This font has been proposed to make reading much easier and more fluent for individuals with dyslexia. By conducting a carefully-designed study with a range of controls, we were able to demonstrate that, although all readers, including those with dyslexia, read the Dyslexie font slightly faster than other fonts, this benefit was attributable entirely to the increased spacing between the letters in the words. If letter spacing is increased similarly in other standard fonts, such as Arial, the same advantage occurs. This finding, published in the journal Dyslexia (Marinus, et al., 2016) received widespread media attention, and provides one of many examples of translation of research into practice by the CCD Reading Program.