Luminance and chromatic contrast sensitivity in dyslexia: The magnocellular deficit hypothesis revisited

Dorota B. Bednarek, Anna Grabowska

Research output: Contribution to journalArticlepeer-review

31 Citations (SciVal)

Abstract

The hypothesis of a magnocellular channel deficit in dyslexia was tested. Subjects were 10-year-old dyslexics and normal readers. Psychophysical thresholds for luminance and chromatic contrasts were estimated using black and white and red and green sinusoidal gratings of various spatial frequencies, presented in static and dynamic conditions (drift and reversal). Significant group differences were found for luminance contrast, with a higher sensitivity in dyslexics. No group differences were obtained for chromatic contrast. High luminance contrast sensitivity correlated with low reading and writing skills. The typical finding of an increase contrast sensitivity to low spatial frequency gratings, due to their dynamic presentations, was absent in dyslexics. The results provide support for the magnocellular deficit hypothesis. The pattern of this deficit, however, is much more complex than that emerging from previous research.

Original languageEnglish
Pages (from-to)2521-2525
Number of pages5
JournalNeuroreport
Volume13
Issue number18
DOIs
Publication statusPublished - 20 Dec 2002

Keywords

  • Chromatic contrast sensitivity
  • Dyslexia
  • Luminance contrast sensitivity
  • Magnocellular channel

ASJC Scopus subject areas

  • Neuroscience(all)

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