The growth of knowledge about learning disabilities has seemed to be much like a young stream; meandering around differing theories as we have learned more about the genetics, presentation, and remediation of various conditions. Knowledge regarding reading disorders, specifically, had its beginnings in theories emphasizing visual perception, perceptual-motor integration, cortical dominance, and ultimately psycholinguistics; progressively being refined by improved neuroimaging and genetic analysis to a recent and extended period of interest in the so-called phonological processing hypothesis. In fact, support for the concept that phonological processing deficits represent the main channel of the stream (which is widening and gaining force) has resulted in our prototypical assessment strategies and intervention recommendations increasingly being robotically focused upon a narrow emphasis—the phonemic unit.
Mody and Silliman's new book challenges this complacency by reminding us of the complexities of individual differences, the impact of early atypicalities upon subsequent brain development, and the role of both critical periods and cultural factors as they impact the growing organism. Much as a log jam alters the flow of the river and causes collateral pathways and pools, each brain's unique development forces us to respect that there will never be a singular cause or treatment for dyslexia. This book provides reviews of current thinking regarding reading and language disabilities, their development, phenotype, and ultimately their remediation.
I found some chapters of the book quite challenging to wade through, as competing theories were rapidly presented, contrasted, supported, or challenged, and I found myself occasionally experiencing that familiar feeling from graduate school that I am not really as smart as I wish. Other chapters were more digestible, however, with clear summarization of the major points the authors were presenting. My thinking gained added clarity from a chapter by Virginia Berninger, which helped me to see alternatives to the popular phonological-centric models of reading, by emphasizing the roles of working memory and executive control processes. Differentiation of children who have oral language and receptive/expressive written language disorders helped me to feel more confident in my ability to disentangle the presenting challenges of the children I evaluate. Sections on functional neuroimaging confirmed my growing understanding that localization of function is less important than appreciating the complementary and interactive roles of multiple brain circuitries and regions and that impairment in function could be secondary to disruption in any of a multitude of neurocognitive processes.
Later sections of the book reviewed questions such as the relative value of differing approaches to pre-literacy intervention, focusing upon skills related to extracting meaning from text versus skills related to decoding print itself. The point made is that not all children have primary phonological processing deficits—some have primary oral language disorders, some have other information processing disorders, and some have complex combinations of causative factors. Planning for intervention should therefore focus upon matching the developmental and skill-based needs of the child with differing intervention models and processes. Different interventions likely have different impacts upon different children at different ages with different underlying problems. Naturally, all of this needs to be considered within the language and cultural backdrop of the child's family, the child's early exposure to co-reading, and instruction about the structure of language, in general. As emphasized in a chapter reviewing two longitudinal studies of early intervention, we now know that children who present with a familial risk factor for reading disabilities are responsive to targeted and developmentally appropriate interventions, with early intervention effects persisting into later childhood. What is also clear, however, is that not all children respond to any single intervention, and that if all we have is a hammer, we need more tools.
The final section of the book emphasizes the role of experience and exposure in the development of children. An emphasis is placed upon understanding the whole child, their family, socioeconomic status, and overall oral language skills. It is suggested that we do not yet have good data on the interaction of these multiple variables with the outcome of specific forms of intervention and that more success could potentially be obtained by matching our interventions to the specific situation/needs of the child. Discontinuities in responses to intervention may reflect the interactions of dynamic systems, which need to “come together” in the right way at the right time, to produce rapid gains in knowledge and competency. Nelson and Arkenberg argue that narrow assessments of decontextualized individual competencies will be unlikely to result in a package of instructional modalities that can help a struggling child to “get it” and move forward at the rate their potential might predict. For neuropsychology practitioners, this again emphasizes our need (and frequent failure) to look at what is right about a child, in addition to what is wrong.
As a whole, I found Mody and Silliman's book to be a thoughtful presentation of the multitude of issues on which we, as practicing neuropsychologists, must focus. I was humbled by the complexity of the issues and how easily my day-to-day practice may gloss over important considerations as I go about the clinical application of my current knowledge regarding reading and language development. At the same time, I was disappointed that a greater emphasis was not given to the role of subcortical factors as they affect language and reading. Given that we are increasingly aware of the role of frontostriatal pathways and cerebellar functions as they impact neuropsychological functioning, I was hoping that the book would have had a chapter that provided at least an introductory integration of cortical and subcortical contributors to language and reading disorders. In sum, Mody and Silliman's book is a worthwhile addition to the bookshelf, but perhaps best digested in small bites.