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Specific Deficits in Component Reading and Language Skills: Genetic and Environmental Influences.
Peer reviewed Peer reviewed
Olson, Richard; And Others – Journal of Learning Disabilities, 1989
Word recognition data from identical and fraternal twins and siblings (N=172) indicated that the phonological coding deficit of children with reading disabilities was highly heritable. Orthographic coding was not significantly heritable. Poor readers with low IQs were superior to similar reading but average IQ readers in phonological coding.…
Descriptors: Elementary Secondary Education, Genetics, Heredity, Intelligence Differences
The External Validity of Age-versus IQ-Discrepancy Definitions of Reading Disability: Lessons from a Twin Study.
Peer reviewed Peer reviewed
Pennington, Bruce F.; And Others – Journal of Learning Disabilities, 1992
This study of 640 twins with reading disability and 436 controls (mean age 12) examined external validity of the distinction between specific reading retardation and reading backwardness, in 3 domains: genetic etiology, sex ratio and clinical correlates, and neuropsychological profiles. There was no evidence of differential genetic etiology of the…
Descriptors: Age Differences, Definitions, Educational Diagnosis, Elementary Secondary Education
Differential Genetic Etiology of Reading Disability as a Function of IQ.
Peer reviewed Peer reviewed
Wadsworth, Sally J.; Olson, Richard K.; Pennington, Bruce F.; DeFries, John C. – Journal of Learning Disabilities, 2000
Composite reading performance data from 223 pairs of identical twins and 169 same-gender fraternal twins in which at least one member was classified with reading disability were subjected to multiple regression analysis. Results indicated that the genetic etiology of reading disability differs as a linear function of IQ. (Contains extensive…
Descriptors: Biological Influences, Children, Disability Identification, Environmental Influences