The Double-Deficit Hypothesis: The origin story of heterogeneity and dyslexia

Wolf and Bowers’ 1999 paper, her most influential, showed that naming speed is a second source of reading failure, separable from phonology. Children with both deficits struggle most. Wolf, explaining it in her own words:

There are these kids who have single deficits in phoneme awareness, single deficits in naming speed without phoneme, and then double-deficit kids who have both. The kids who have both reading fluency and comprehension issues have different reasons for reading failure than the kids who have only phoneme awareness issues.

— Maryanne Wolf, Children of the Code interview

Read the original 1999 paper (free PDF).

Related in the Nest: What rapid naming tells us · The full interview · Screening before struggle