Major Findings from NICHHD-Supported Research Programs

• Reading disabilities affect at least 10 million children in the United States (Yale University).

• Epidemiologic studies indicate as many females as males manifest dyslexia; however, schools identify four times as many boys as girls (Bowman Gray School of Medicine, University of Colorado, Yale University).

• Reading disabilities reflect a persistent deficit rather than a developmental lag.   Longitudinal studies show that of  those children who are reading disabled in the third grade, approximately 74% remain disabled in the ninth grade (Yale University, Ontario Institute for Studies in Education)

• Distinguishing between disabled readers with and without an IQ-achievement discrepancy appears invalid.  Children with and without discrepancies show similar information processing, genetic, and neurophysiologic profiles (University of Colorado, Bowman Gray School of Medicine, Yale University, Ontario Institute for Studies in Education).

• The ability to read and comprehend depends on rapid and automatic recognition and decoding of single words.  Slow and inaccurate decoding are the best predictors of deficits in reading comprehension (Yale University, Bowman Gray School of Medicine, University of Colorado, Johns Hopkins School of Medicine).

• The ability to decode single words accurately and fluently is dependent on the ability to segment words and syllables into phonemes.  Deficits in phonologic awareness reflect the core deficit in dyslexia (Yale University, University of Colorado, Bowman Gray School of Medicine, University of Miami, Johns Hopkins School of Medicine).

• The best predictor of reading ability from kindergarten and first-grade performance is phoneme segmentation ability (Bowman Gray School of Medicine, Yale University).

• There is strong evidence for genetic etiology of reading disabilities, with deficits in phonologic awareness reflecting the greatest degree of heritability (University of Colorado).

• Disabled readers do not readily acquire the alphabetic code due to deficits in phonologic processing.  Thus, disabled readers must be provided highly structured programs that explicitly teach application of phonologic rules to print (Bowman Gray School of Medicine).

• Longitudinal data indicate that systemic phonics instruction results in more favorable outcomes for disabled readers than does a context-emphasis (whole-language) approach (Bowman Gray School of Medicine).

• Children at risk for reading failure learn to read words more fluently and accurately if they are explicitly taught phoneme awareness and sound-symbol relationships (University of Houston, Florida State University, University of Colorado, University of New York at Albany).

• Instruction in phonology does not generalize to better text comprehension spontaneously; children also need to be taught how to read fluently and comprehend the meaning of what they read (Florida State University, University of Houston, University of Colorado).