How specific are "specific developmental disorders"? The relevance of the concept of specific developmental disorders for the classification of childhood developmental disorders

Classification of psychiatric disorders in childhood and adolescence: building castles in the sand?

A classification system can benefit disturbed children enormously by bringing to bear a wealth of knowledge and experience. This can make all the difference between an inadequate consultation and a precise formulation of the nature and extent of a child's difficulties, their cause, the likely outcome and a realistic treatment plan. However, inappropriate application of a diagnostic label that has little validity could do more harm than good, and classification systems can be misused. This paper discusses, with examples, issues particular to childhood and adolescence that diagnostic systems need to address if they are to be useful. It considers different solutions applied by the two most widely used schemes, theInternational Classification of Diseases(ICD–10; World Heath Organization, 1992) and theDiagnostic and Statistical Manual of Mental Disorders(DSM–IV; American Psychiatric Association, 1994). Finally, the types of criteria used to validate categories are discussed.

Disorders of attention or learning in neurodevelopmental disorders

Disorders of attention or learning commonly accompany neurodevelopmental disorders. The evaluation and diagnosis of these disorders is complex and does not always follow techniques used for typically developing children. These disorders are often underappreciated and inadequately addressed because they are overshadowed by the neurodevelopmental disorder. Nevertheless, failure to recognize, diagnose, and manage these disorders may result in unsuccessful community integration.

Is the discrepancy criterion for defining developmental disorders valid?

BACKGROUND

Most developmental disorders are defined by an achievement discrepancy in which achievement on one or more specific abilities is substantially less than a person's measured intelligence. We evaluated the validity of this discrepancy criterion by assessing parameters that determine variability across abilities and by assessing relationships between achievement discrepancies and behavioral disturbances.

METHODS

Measures of intelligence, language, motor coordination, empathic ability, and attentional control were administered to a representative sample of 390 children aged 3 to 12 years. Parent ratings of child behavior were obtained.

RESULTS

Results indicate that achievement discrepancies are a function of the correlation between ability measures, the shape of the ability distributions, and position on an index ability dimension. Discrepancies in achievement were not related to behavioral disturbance, but underachievement relative to age peers was invariably related to behavioral disturbance.

CONCLUSIONS

We conclude that developmental disorders need to be redefined in ways that are consistent with how Mental Retardation is now defined, by (a) underachievements, (b) of defined magnitude, (c) using standardized measures, (d) with known relations to normal development, and (e) concurrent deficits on standardized measures of impaired function.

Specific reading disability: a multiplanar view

In the past three decades a revolution has altered the way society approaches people with disabilities. Social changes resulted in a significant increase in fundamental and applied research that seeks to improve the lives of people with disabilities by facilitating better understanding of the mechanisms, manifestations, prevention, and treatment of functional impairment. Specific Reading Disability (SRD) has benefited from this revolution. This review focuses on the evolution of SRD, new information in its neurobiology and management, and the challenges that remain. Evidence from a wide spectrum of research provides strong support for the role of phonology in Specific Reading Disability. Despite the mounting evidence, the case is far from completely established. Adults with compensated SRD read but still demonstrate disordered phonology (Felton et al. [1990] Brain Language 39:485-497). Whether poor phonology is causal or a covariant remains to be demonstrated. Of children with poor phonology, it is not known how many are poor readers. While phonology is associated with SRD, other studies have questioned the uniqueness of SRD. Challenges have been made to the method of classification, the uniqueness of phonological dysfunction as a mechanism in SRD and the response to treatment. In the final analysis all poor readers may have a common core of dysphonology, independent of whether their reading is discrepant from their IQ.

Mathematics and the brain: uncharted territory?

The prevalence of disorders of arithmetic skills in children of circa 6 % calls for intensive consideration of the subject by health care providers and researchers. The necessity of interdisciplinary cooperation is evident. The current classifications by the ICD-10 (Specific disorder of arithmetic skills) and DSM-IV (Mathematics disorder) represent different viewpoints. A developmental dyscalculia is exclusively diagnosed according to clinical presentation. Arithmetic and its disorders are brain functions, determined and influenced by the (cerebral) human development. With modem neuroimaging techniques, a connectionistic model of distinct arithmetic functions has been specified. The results of single case descriptions of arithmetic disorders correspond well in that context with the concept of parallel cortico-subcortical and subcortico-cortical neuronal circuits. In comparison with dyslexia, there is intense need for research in the field of arithmetic disorders. Only through analysis and understanding of the complex cerebral connections in arithmetic can improved diagnostic as well as multidimensionally therapeutic approaches to arithmetic disorders be achieved, possibly opening new ways of academic and social integration of the affected individuals.

Central auditory processing disorder in school-aged children: a critical review

The rationale to evaluate for central auditory processing disorder (CAPD) in school-aged children is based on the assumption that an auditory-specific perceptual deficit underlies many learning problems including specific reading and language disabilities. A fundamental issue in this area is whether convincing empirical evidence exists to validate this proposition. Herein, we consider the issue of modality specificity by examining the extent to which reading, language, and attention disorders in school-aged children involve perceptual dysfunctions limited to a single sensory modality. Difficulty in validating CAPD as a diagnostic label is due in large part to use of the unimodal inclusive framework, which has biased the diagnosis to favor sensitivity of test results over documenting the specificity of the deficit. Indeed, empirical research documenting modality-specific auditory-perceptual dysfunction in this population is scarce. Therefore, the existing literature on this topic has not clarified the "true" nature of the problem, and has left many questions about this disorder unanswered. It is argued that demonstrating modality specificity is one way to rule out supramodal disorders as explanations for observed dysfunction. Multimodal perceptual testing is one logical approach to help clarify this area of investigation.