The presence of a magnocellular defect depends on the type of dyslexia

The presence of a magnocellular defect depends on the type of dyslexia Previous studies have identified a magnocellular pathway defect in approximately 75 % of dyslexics. Since these experiments have not classified dyslexia into subtypes, the purpose of this experiment was to determine if adult dyseidetic dyslexics or dysphoneidetic dyslexics suffer from a defect in the magnocellular pathway. Nine dyseidetic dyslexics, eight dysphoneidetic dyslexics, and nine normal readers participated in the experiment. Contrast sensitivity functions (CSF) were determined with vertically oriented sine wave gratings (0.5, 1.0, 2.0, 4.0, 8.0, 12.0 c/deg drifting at 1 and 10 Hz) by employing a two-alternative, forced-choice technique. The results of the experiment indicated that dysphoneidetic dyslexics had reduced sensitivity to low spatial frequencies at 10 Hz, whereas dyseidetic dyslexics did not have reduced sensitivity at either 1 or 10 Hz. These results suggest that the type of dyslexia influences whether losses in perception are found which are consistent with a magnocellular deficit. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Vision Research Elsevier

The presence of a magnocellular defect depends on the type of dyslexia

Loading next page...
 
/lp/elsevier/the-presence-of-a-magnocellular-defect-depends-on-the-type-of-dyslexia-Jd91xZJoSa
Publisher
Elsevier
Copyright
Copyright © 1996 Elsevier Science Ltd. All rights reserved
ISSN
0042-6989
eISSN
1878-5646
DOI
10.1016/0042-6989(95)00199-9
Publisher site
See Article on Publisher Site

Abstract

Previous studies have identified a magnocellular pathway defect in approximately 75 % of dyslexics. Since these experiments have not classified dyslexia into subtypes, the purpose of this experiment was to determine if adult dyseidetic dyslexics or dysphoneidetic dyslexics suffer from a defect in the magnocellular pathway. Nine dyseidetic dyslexics, eight dysphoneidetic dyslexics, and nine normal readers participated in the experiment. Contrast sensitivity functions (CSF) were determined with vertically oriented sine wave gratings (0.5, 1.0, 2.0, 4.0, 8.0, 12.0 c/deg drifting at 1 and 10 Hz) by employing a two-alternative, forced-choice technique. The results of the experiment indicated that dysphoneidetic dyslexics had reduced sensitivity to low spatial frequencies at 10 Hz, whereas dyseidetic dyslexics did not have reduced sensitivity at either 1 or 10 Hz. These results suggest that the type of dyslexia influences whether losses in perception are found which are consistent with a magnocellular deficit.

Journal

Vision ResearchElsevier

Published: Apr 1, 1996

References

  • Subtypes of dyslexia: Investigation of Boder's system using quantitative neurophysiology
    Flynn, J.M.; Deering, W.M.
  • Contrast sensitivity in dyslexia
    Gross-Glenn, K.; Skottun, B.C.; Glenn, W.; Kushch, A.; Lingua, R.; Dunbar, M.; Jallad, B.; Lubs, H.A.; Levin, B.; Rabin, M.; Parke, L.A.; Duara, R.
  • How parallel are the primate visual pathways?
    Merigan, W.H.; Maunsell, J.H.R.

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create folders to
organize your research

Export folders, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off