Dyslexia: cultural diversity and biological unity

Science. 2001 Mar 16;291(5511):2165-7. doi: 10.1126/science.1057179.

Abstract

The recognition of dyslexia as a neurodevelopmental disorder has been hampered by the belief that it is not a specific diagnostic entity because it has variable and culture-specific manifestations. In line with this belief, we found that Italian dyslexics, using a shallow orthography which facilitates reading, performed better on reading tasks than did English and French dyslexics. However, all dyslexics were equally impaired relative to their controls on reading and phonological tasks. Positron emission tomography scans during explicit and implicit reading showed the same reduced activity in a region of the left hemisphere in dyslexics from all three countries, with the maximum peak in the middle temporal gyrus and additional peaks in the inferior and superior temporal gyri and middle occipital gyrus. We conclude that there is a universal neurocognitive basis for dyslexia and that differences in reading performance among dyslexics of different countries are due to different orthographies.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Brain / blood supply
  • Brain / diagnostic imaging
  • Brain / physiopathology*
  • Cross-Cultural Comparison
  • Culture*
  • Dyslexia / etiology*
  • Dyslexia / physiopathology
  • France
  • Humans
  • Italy
  • Language*
  • Male
  • Matched-Pair Analysis
  • Occipital Lobe / blood supply
  • Occipital Lobe / diagnostic imaging
  • Occipital Lobe / physiopathology
  • Reading
  • Regional Blood Flow
  • Temporal Lobe / blood supply
  • Temporal Lobe / diagnostic imaging
  • Temporal Lobe / physiopathology*
  • Tomography, Emission-Computed
  • United Kingdom