The convolutional surface area of the planum temporale, temporal lobe volume, and brain volume were compared by MRI in 17 dyslexic children (7 girls) and 14 controls (7 girls) at Yale University School of Medicine, New Haven. All measurements were significantly larger in boys. Age was directly correlated with brain region volumes. Analyses that controlled for age and overall brain size failed to confirm smaller left hemisphere structures previously reported in dyslexics. The authors suggest that differences in sex, age, handedness, and definition of dyslexia as well as methods of measurement of the planum temporale may explain apparent discrepancies in results of neuroimaging studies in dyslexic subjects. [1]

COMMENT. This important study casts doubt on the significance of reports of differences in brain morphology in children with dyslexia and other learning disabilities. It should be noted in the Massachusetts General Hospital report of corpus callosal changes in ADDH children, a smaller splenium was unrelated to the age of the children, (see above).

Age-related changes in the brains of patients with Down’s syndrome measured by MRI analyses are reported from the University of California, Irvine. [2]

The changing conception of mental retardation and the implications of the new 1992 American Association on Mental Retardation’s (AAMR) definition and classification are outlined by psychologists, psychiatrists, pediatricians, pediatric neurologists, and educators [3]. The 1992 System shifts the diagnostic effort from estimating the level of an individual’s deficiency (mild, moderate, severe) to the intensities of needed supports (intermittent, limited, extensive, pervasive). Professional/clinical judgement is emphasized in assessments, and the terms educable and trainable are considered inappropriate. Special education services and supports are based on functioning level rather than IQ-derived levels of retardation. An etiological classification of biological or psychosocial categories is modified and expanded to a multifactorial approach which includes intergenerational and environmental factors. Research studies based on the new paradigm will emphasize environments and supports, quality of life, and a greater precision in definition.