The author reviews the theories of S. Orton relating neurological factors to dyslexia. He further considers possible advantages of a predisposition to dyslexia, including the possession of talents. He answers four common critiques of Orton's biological approach to dyslexia, and suggests instead, the advantages of such an approach. (CL)

Lauretta Bender's experiences as a bright child struggling with specific learning problems and her subsequent work in language disorders are described. Her recognition of the biological nature of a group of learning disorders for which there was no clinical evidence of structural damage to the central nervous system is emphasized. (JDD)

The author considers cerebral dominance and brain asymmetry, the development of the cerebral cortex and examples of aberrancy, and diseases of the immune system, all of which relate to recent anatomical and epidemiological findings in developmental dyslexia. These discoveries have led to testable hypotheses which may enhance current understandings…

This study of 11 3-generation families supported the hypothesis of autosomal dominant inheritance with reduced penetrance. Data did not support an increased frequency of males, left-handedness, or autoimmune disorders in dyslexics. Severity was greater in males. Long-term outcome was comparable in dyslexics and nondyslexics. (JDD)

Autopsy analysis of eight dyslexic brains found that the ordinary asymmetry in a language-relevant area of the temporal lobe was missing. The greater development of the right side may reflect an increase in the total number of neurons involved in language processing, resulting in changes in interhemispheric interactions. (JDD)

This article reviews recent evidence supporting a biological basis for developmental dyslexia. It concludes that the combined evidence demonstrating macroscopic morphologic, microscopic neuronal, and microstructural white matter abnormalities in dyslexia is consistent with a localization of the principle pathophysicological process to perisylvian…

The article notes correlations between lefthandedness and the incidence of immune disorders (such as ileitis, colitis, celiac disease, and Hashimoto's thyroiditis), with learning disorders and with early grey hair. Eventual control of the hormonal and immune environment (in addition to educational intervention) may prevent or minimize these…

A study assessed genetic and environmental etiologies of reading, rapid naming (RN), and their covariation using data from 587 twin pairs (ages 7-20) in which one student had reading difficulties and from 360 control pairs. Correlation between reading and RN performances for subjects was significantly higher than that of controls. (Contains…

This article discusses the contributions of Margaret Byrd Rawson in the field of dyslexia. She was instrumental in the founding of the Jemicy School in Maryland, served as President of the International Dyslexia Association (IDA), and was on the IDA Council of Advisors at the time of her death. (CR)

A twin study involving 808 children with reading disability (RD) and 455 children with phonological disorder (PD) found each were heritable on their own. Further, even when correcting for RD, the two disorders were found to be co-heritable, indicating co-familiarity is at least partially driven by genetic influences. (Contains references.)…

This article reviews the contributions of Norman Geschwind on behavioral neurology. It discusses his novel associations between brain function/structure and behavior and findings from a recent study of 200 individuals with developmental disorders that indicate altered neuroanatomy in dyslexia may be accompanied by altered clinical neurophysiology.…

This article focuses on methods useful for identifying differences in the development of language reading abilities in children that rely on measures of brain responses and behavioral assessments. Findings from these methods are described and indicate that even behaviors strongly influenced by biological mechanisms can be influenced through…

This article reviews diagnostic criteria for attention deficit hyperactivity disorder and undifferentiated attention deficit disorder; typical presenting features; theories of the biological basis of attentional disorders; and treatments, including medical treatments with stimulants and tricyclic antidepressants and nonmedical treatments such as…

Preliminary results from data on 146 Australian, 284 American, and 70 Norwegian preschool twins indicate reliable genetic influences on phonological awareness and memory and learning. Vocabulary, grammar, and morphology showed significant shared environment and negligible genetic effects. A print knowledge composite showed genetic and shared…