The problem with diagnosis is that it is often viewed as being largely concerned with labeling and classifying, rather than understanding.

J. Bruce Tomblin and Kathryn L. Mueller (2012a, p. 196) in their Issue Editor - Foreword

In this issue of Topics in Language Disorders, issue editors J. Bruce Tomblin and Kathryn L. Mueller, along with their invited authors, help readers consider relationships of attention-deficit/hyperactivity disorder (ADHD) and communication disorders-including language, speech, and reading disorders-from multiple angles. I selected a sentence from the Issue Editor Foreword (Tomblin & Mueller, 2012a) as the opening quotation for this column because it provides its own unique angle on the contents of the issue. Specifically, it raises questions about distinctions in how medical diagnosticians and educational practitioners look at issues of diagnosis when the question is not one of diagnosing disease or illness but rather diagnosing developmental behavioral disorders involving attention, language, speech, and reading-occurring either specifically or together in an individual.

As the issue editors point out in their Foreword (Tomblin & Mueller, 2012a) and introductory article (Tomblin & Mueller, 2012b), diagnosis of a set of behaviors that defines a phenotype (e.g., language impairment, speech sound disorder, or dyslexia) has implications for understanding layers of genetic, neural, and cognitive factors (and related environmental influences) that affect the ultimate phenotypic expression (i.e., diagnosis). These may be overlooked, however, when the co-occurrence of two conditions is so frequently encountered as to be taken for granted.

Just as photographic angles shed light differently on tangible things, making previously hidden features visible, the authors of this issue consider ADHD from different angles, shedding light differently on the intangible diagnoses of language impairment, speech sound disorders, and dyslexia. The first article in this issue (Tomblin & Mueller, 2012b) is a thought-provoking overview of different angles on possible mechanisms of comorbidities. It is followed by two articles by Mueller and Tomblin (2012a, 2012b), focusing first on the diagnosis of ADHD alone and then on the view of ADHD from the angle of its comorbidity with language impairment. Next, Lewis et al. (2012) view ADHD from the angle of its co-occurrence with speech sound disorders. Finally, Boada, Willcutt, and Pennington (2012) view ADHD from the angle of its co-occurrence with dyslexia. All of the authors consider genetic factors, as well as other endophenotypic systems (neural and cognitive), which may explain comorbidity or be explained by it.

Readers should find plenty of food for thought in this issue. Whether they are researchers or practitioners, I expect that readers will agree that considering these levels of influence from all angles can shed new light on the nature of ADHD, alone or in co-occurrence with disorders of language, speech, and reading. Collectively, these articles should raise appreciation for the value of careful diagnosis as a matter of understanding a person's comprehensive patterns of strengths and needs, along with potential underlying and explanatory factors. Such diagnostic purposes emphasize meanings of both theoretical relevance and clinical relevance. They extend the more purely functional, although still important, purposes of determining eligibility for services or funding.

-Nickola Wolf Nelson, PhD

Editor

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