Bruce Pennington's book Diagnosing Learning Disorders: A Neuropsychological Approach (2nd ed.) provides coverage of not only theoretic models of learning disabilities, but also a practical guidance helpful to any practitioners working with children who have learning disabilities. The 13 chapters of the book are organized into three main sections: Basic Concepts, Review of Disorders, and Implications for Practice and Policy.
The Basic Concepts section, which includes Chapters 1–5, covers a range of topics concerning the validity of the learning disabilities concept and differentiating valid from invalid concepts of disorders. The chapter on Neuropsychological Constructs provides a concise review of relevant literature from neuropsychology, cognitive neuroscience, and psychometrics in selecting which cognitive constructs are essential in understanding learning disorders. Carroll's psychometric, hierarchical, three stratum model that includes Fluid and Crystallized intelligence is reviewed and demonstrated using the WISC-IV. Constructs from cognitive neuroscience are also reviewed with a focus on what the author asserts are the most important for differentiating the disorders listed in the book: Language, Executive Functions, and Social Cognition. The Basic Concepts section also includes a model of syndrome validation, which includes both internal and external validity. The model, and provided examples, illustrates the complex nature of syndrome identification and the difficulties involved in diagnosis. The model is demonstrated in the “Less Well-Validated Learning Disorders” chapter to identify disorders that fall-short of the provided criteria of a validated learning disorder. Some of the disorders reviewed in this chapter include Central Auditory Processing Disorder and Sensory Modulation Disorder. In both cases, the validity of the disorder is called into question on grounds of theoretical plausibility, external validity, and lack of differentiation from well-validated disorders.
The second section of the book, Review of Disorders, includes eight chapters with each covering a different disorder. Some chapters include co-authors. The disorders covered are: Dyslexia, Speech and Language Disorders, Autism Spectrum Disorder, Attention-Deficit/Hyperactivity Disorder, Intellectual Disability, Developmental Coordination Disorder, Mathematics Disorder, and Nonverbal Learning Disability. Each chapter provides an in-depth review of the history of the disorder, a review of research, definition, epidemiology, etiology, neural correlates, and neuropsychology. In addition, each chapter covers the defining symptoms, comorbidities, developmental history, diagnosis, prognosis, and treatment for each disorder. A Clinical Summary Table at the end of each chapter succinctly reviews the critical information covered in each chapter. Readers without time to read the book cover to cover may find the summary tables a sufficient start point prior to deciding which chapters to read in more depth.
The chapter on Dyslexia is of special importance given the significant controversy on this topic and given the high prevalence rate of the disorder. Controversial aspects of dyslexia, ranging from its construct validity to how it is diagnosed, are directly addressed. Pennington provides ample research to support Dyslexia as a disorder of neurological origins and few readers could come away with a belief that dyslexia is caused solely by poor education, although environmental aspects are not discounted. Pennington defines dyslexia as poor word recognition relative to age, which has become a consensual, albeit simplified, definition in the field. In addition, Pennington adheres to the neuropsychological cause as attributed to phonological coding and phonological representations. A helpful model of reading is provided that begins with the overall goal of reading instruction, Reading comprehension, and its components of Fluent Word Recognition, Listening Comprehension, and Discourse Specific Skills. Each of these components is broken down into other components or precursors. Appealing to practitioners, the chapter is complete with caveats for collecting background information, behavioral observations, and interpreting symptoms, and two case studies are provided to demonstrate interpretation. Perhaps of greatest value is a concise, yet thorough, review of evidence-based treatments for dyslexia. In conjunction with other researchers, direct instruction in addition to phonological interventions is recommended as the most validated treatment for dyslexia. Here, Pennington reveals a support for Response to Intervention Models (RTI) but with an appropriate caution. This caution mainly comes from recent research revealing implementation difficulties in RTI and a lack of empirical evidence demonstrating the effectiveness of RTI in treating dyslexia. Other disorders are reviewed with similar detail.
The third section, Implications for Practice and Policy, breaks new ground on a critical issue on defining “evidence-based” practice and interventions. Tough topics are addressed such as the interaction of social values on science and how values can mislead practice. Pennington endorses a solution in which treatments for learning disorders are rated by levels of empirical support, similar to medical research, and proposes a central organizing unit to provide accountability for interventions used to treat learning disorders.
Pennington's book is not only highly recommended to anyone working with children having disabilities, but also highly recommended for students in training. The book covers a broad range of issues that are of essential importance in effective practice. In covering such breadth, some depth is sacrificed. For example, Carroll's psychometric model includes at least seven broad abilities but only Fluid and Crystallized abilities were reviewed in detail. In addition, applications of Carroll's model to the WISC-IV factors was incomplete, given constructs like Working Memory in the WISC-IV are not in Carroll's original model. Similarly, Language, Executive Functions, and Social Cognition were identified as the most influential cognitive abilities in understanding disorders, but how these constructs relate to Carroll's model was not well-integrated. The treatment of learning disabilities without doubt would benefit from better regulation of evidence-based treatments, but establishing a government-like agency to regulate the use of such treatments may prove more harmful than not. Certainly, however, Pennington provides much food for thought in tackling such tough issues, which usually go untouched by other books on similar topics. In all, Pennington's delicate balance of covering a large number of topics and disorders with sufficient breadth and depth, with appeal to both researchers and practitioners, makes Pennington's book Diagnosing Learning Disorders: A Neuropsychological Framework (2nd ed.) one of the most valuable books available on the topic.