Functional neuroanatomical evidence for the double-deficit hypothesis of developmental dyslexia

Elizabeth S. Norton, Jessica M. Black, Leanne M. Stanley, Hiroko Tanaka, John D E Gabrieli, Carolyn Sawyer, Fumiko Hoeft*

*Corresponding author for this work

Research output: Contribution to journalArticle

39 Scopus citations

Abstract

The double-deficit hypothesis of dyslexia posits that both rapid naming and phonological impairments can cause reading difficulties, and that individuals who have both of these deficits show greater reading impairments compared to those with a single deficit. Despite extensive behavioral research, the brain basis of poor reading with a double-deficit has never been investigated. The goal of the study was to evaluate the double-deficit hypothesis using functional MRI. Activation patterns during a printed word rhyme judgment task in 90 children with a wide range of reading abilities showed dissociation between brain regions that were sensitive to phonological awareness (left inferior frontal and inferior parietal regions) and rapid naming (right cerebellar lobule VI). More specifically, the double-deficit group showed less activation in the fronto-parietal reading network compared to children with only a deficit in phonological awareness, who in turn showed less activation than the typically-reading group. On the other hand, the double-deficit group showed less cerebellar activation compared to children with only a rapid naming deficit, who in turn showed less activation than the typically-reading children. Functional connectivity analyses revealed that bilateral prefrontal regions were key for linking brain regions associated with phonological awareness and rapid naming, with the double-deficit group being the most aberrant in their connectivity. Our study provides the first functional neuroanatomical evidence for the double-deficit hypothesis of developmental dyslexia.

Original languageEnglish (US)
Pages (from-to)235-246
Number of pages12
JournalNeuropsychologia
Volume61
Issue number1
DOIs
StatePublished - Aug 2014

Keywords

  • Developmental dyslexia
  • Double deficit
  • FMRI
  • Phonological processing
  • Reading

ASJC Scopus subject areas

  • Experimental and Cognitive Psychology
  • Cognitive Neuroscience
  • Behavioral Neuroscience

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