Brain Activation During Reading in Deep Dyslexia: An MEG Study

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© 2000 MIT Press. This is the final version of the article: Laine, Matti ; Salmelin, Riitta ; Helenius, Päivi ; Marttila, Reijo. 2000. Brain Activation During Reading in Deep Dyslexia: An MEG Study. Journal of Cognitive Neuroscience. Volume 12, Issue 4. P. 622-634. ISSN 0898-929X (printed). DOI: 10.1162/089892900562381, which has been published in final form at http://www.mitpressjournals.org/doi/abs/10.1162/089892900562381#.VVmqOGOkuSo

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Volume Title

School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2000

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Mcode

Degree programme

Language

en

Pages

622-634

Series

Journal of Cognitive Neuroscience, Volume 12, Issue 4

Abstract

Magnetoencephalographic (MEG) changes in cortical activity were studied in a chronic Finnish-speaking deep dyslexic patient during single-word and sentence reading. It has been hypothesized that in deep dyslexia, written word recognition and its lexical-semantic analysis are subserved by the intact right hemisphere. However, in our patient, as well as in most nonimpaired readers, lexical-semantic processing as measured by sentence-final semantic-incongruency detection was related to the left superior-temporal cortex activation. Activations around this same cortical area could be identified in single-word reading as well. Another factor relevant to deep dyslexic reading, the morphological complexity of the presented words, was also studied. The effect of morphology was observed only during the preparation for oral output. By performing repeated recordings 1 year apart, we were able to document significant variability in both the spontaneous activity and the evoked responses in the lesioned left hemisphere even though at the behavioural level, the patient's performance was stable. The observed variability emphasizes the importance of estimating consistency of brain activity both within and between measurements in brain-damaged individuals.

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Keywords

dyslexia, cortical activity, magnetoencephalography

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Citation

Laine, Matti & Salmelin, Riitta & Helenius, Päivi & Marttila, Reijo. 2000. Brain Activation During Reading in Deep Dyslexia: An MEG Study. Journal of Cognitive Neuroscience. Volume 12, Issue 4. P. 622-634. ISSN 0898-929X (printed). DOI: 10.1162/089892900562381.