In science one tries to tell people, in such a way as to be understood by everyone, something that no one ever knew before. But in poetry, it's the exact opposite.1 - -Paul Dirac (1902-1984)
This first issue of 2008 is about science and literacy, if not poetry. Science and poetry were contrasted by Nobel Prize winning physicist, Paul Dirac, for effect. They have in common, however, original thinking. With her own original thinking, Issue Editor, Dr. Linda Siegel, has led a number of strands of scientific inquiry regarding the nature of learning disabilities, including dyslexia. With this issue, Siegel and other authors have applied original thinking and scientific methodology to uncover information about less studied aspects of dyslexia, related to its linguistic underpinnings and the neurologic processes that underlie them.
What is unique about the articles in this issue is that they present results of original research about the components of linguistic processing that, though not ignoring the role of phonologic processing components, go beyond them. Also, in parallel with Dirac's quote at the beginning of this column, these articles benefit from contrasting one phenomenon with another. The resulting effect is that components of dyslexia assume clearer focus than they would if contrasts were not so explicitly drawn.
In writing her book titled simply, Dyslexia, Snowling (2000) highlighted the fact that, although multiple terms are accepted for reading disabilities, "It is only the use of the term 'dyslexia' to describe these problems that has been controversial since its inception" (p. 2). Snowling added that "the controversy centres around whether dyslexia can be differentiated from other forms of reading problem" (p. 2). She went on to describe historical attempts that led to understanding dyslexia as a verbal deficit rather than a visual one, and then outlined the case for a primary deficit involving the phonologic system of language for mapping speech sounds onto units of meaning and the symbols that represent them.
The authors in this issue of Topics in Language Disorders (TLD) present evidence that not only draws on those arguments but also extends the discussion of linguistic deficits in dyslexia beyond phonologic processing. They consider the effects of contrasting units of different sizes, learning to read in different languages, and evidence of different processing patterns for children with dyslexia in early developmental interactions and neurological events. In doing so, these authors apply a variety of scientific methods, with different age groups and diverse language-learner populations. The collection sheds new light on lesser known aspects of dyslexia, but in an accessible manner (as per Dirac) and with implications for clinical application. This combination represents a prime example of translational research, with direct implications for bridging research to practice.
Smith, Locke, and Farkas report on the results of unique methods to gather evidence about the analyzed communication samples of pre-school-aged children whose family characteristics suggested that they were at high risk of dyslexia. This research team identified several early appearing distinctions in the timing and semantic relatedness in discourse of children who later met criteria for dyslexia compared with those who did not. Interestingly, at age 3 years, children later identified with dyslexia, showed more wait time, and were less likely to overlap their adult communication partner's turns than children who learned to read normally. They also consistently showed signs of being able to respond appropriately to the meaning of the message. These findings with 3-year-olds are consistent with other reports differentiating the patterns of linguistic ability for children with broader forms of language impairment from those with dyslexia alone (Catts, Hogan, & Adlof, 2005; Nation & Snowling, 2004).
As Siegel reports in this issue, she studied how sixth-grade students, some of whom were English language learners and some of whom had reading difficulties, were able to apply knowledge of information about derivational morphology to read and spell pseudowords. She found that difficulties with morphological awareness may contribute significantly to the reading and spelling problems of children with dyslexia, particularly as they get older. This has implications for assessment and intervention. Siegel included her assessment protocols as well, which should be of particular interest to practice-minded TLD readers.
Also in this issue, Molfese, Molfese, Beswick, Jacobi-Vessels, Molfese, Molnar, Wagner, and Haines report on their research measuring neural responses to specific linguistic events. These methods allowed them to shed new light on the relationships of genetic and biological influences, exposure to the language environment, and maturational processes on the processing of small units of linguistic information. Molfese et al. found that children who were good at word decoding also had neural responses to phonetic information that were different, reflecting greater responsivity to small phonetic distinctions than did neural responses for children with poor decoding skills.
Jimenez, Hernandez-Valle, Rodriguez, Guzman, Diaz, and Ortiz investigated the double deficit hypothesis for understanding the nature of dyslexia by working with children learning to talk and read in Spanish as their native language. They identified groups of children between ages 7 and 13 years who met criteria as having difficulties in phonological processing, naming speed, or both. The transparent orthography of Spanish presented unique opportunities to study the relative influences of difficulties with both of these contributing abilities. Jimenez et al. found that students with deficits in both areas had the most difficulty with reading (suggesting a dimensional difference), but they also found that naming speed difficulty alone was associated more with problems of reading fluency whereas difficulty with phonemic awareness alone was associated more with problems of decoding.
When children are learning to read in English, but their first language at home is Spanish, a different set of questions arises. Townsend and Collins investigated questions with important clinical implications for educators seeking to make appropriate early intervention decisions about children who are learning English as a second language. Their results support the appropriateness of assessing English language learners' early reading in English when it is the language of reading instruction even though it may not be a child's first language. This information has high practical value for many TLD readers. It may help avoid the feared overidentification of children with reading difficulties from diverse cultural-linguistic groups, while also avoiding equally problematic delays in identification and service delivery due to concerns about cultural-linguistic test bias.
As illustrated by the collected articles in this issue, good science is stimulated by novel and insightful questions. Evidence-based clinical practice relies also on questions about, and attention to, a particular child's and family's needs. A primary purpose of this journal is to provide a forum for discussing cutting-edge topics that cross international and discipline-specific boundaries and that cross basic research and applied practice boundaries as well, always with an eye toward improving the lives of individuals with language disorders and other communication difficulties. We think this issue meets that purpose beautifully and will be consulted frequently as a helpful resource for researchers and clinicians alike.
Nickola Wolf Nelson, PhD, Editor
Katharine G. Butler, PhD, Editor Emerita
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