The prevalence of reading disabilities among very-low-birth-weight children at 9 years of age—dyslexics or poor readers?

Abstract

In this study, 70 very-low-birth-weight (VLBW) children (<1500 g) were compared with 72 normal-birth-weight (NBW) children on different academic achievement tests and behavioural skills. The purpose was to address both the prevalence and type of reading difficulties displayed in a sample of VLBW children, and thus the validity of the IQ–achievement discrepancy definition for developmental dyslexia. The results showed that VLBW children performed statistically more poorly on most academic achievement tests. The data also indicated that VLBW children were less likely to be defined as dyslexic compared with NBW children, despite the fact that the number of poor readers was larger in the VLBW group. Finally, there were no differences between poor readers with low intelligence and poor readers with normal intelligence on eight out of nine different tests measuring cognitive processes underlying reading skills. Instead, differences between subgroups of poor readers were found for behavioural variables, indicating that differences between poor readers and dyslexics are mainly restricted to areas outside the reading domain. Thus the results confirm that the distribution of reading skills of poor readers of both high and low intelligence is very similar and that the use of IQ–achievement discrepancy definitions does not constitute a valid approach to define subgroups of poor readers. Copyright © 1999 John Wiley & Sons, Ltd.