Dement Neurocogn Disord.  2016 Sep;15(3):82-87. 10.12779/dnd.2016.15.3.82.

Ideographic Alexia without Involvement of the Fusiform Gyrus in a Korean Stroke Patient: A Serial Functional Magnetic Resonance Imaging Study

• Yang J
• Kim N
• Lee H
• Park KH

• KMID: 2442850
• DOI: http://doi.org/10.12779/dnd.2016.15.3.82

Abstract

BACKGROUND
Korean orthography is composed of Hanja (ideograms) and Hangul (phonograms). Based on previous studies, the fusiform gyrus has been associated with ideogram reading. We examine serial functional magnetic resonance imaging (fMRI) images in a patient exhibiting dissociation of Hanja and Hangul reading to identify brain areas associated with Hanja reading.
CASE REPORT
fMRI were taken of a 63-year-old man showing profound Hanja alexia with normal Hangul reading after an acute stroke involving the left frontal and parietal lobes, who later spontaneously recovered his Hanja reading ability. Scans were taken while performing Hanja and Hangul reading tasks on three occasions. As a result, in spite of having profound Hanja alexia, partial activation of the fusiform gyrus was observed on the first fMRI. Serial fMRI scans showed activation of the bilateral middle frontal gyri that increased in parallel with the patient's recovery of Hanja reading.
CONCLUSIONS
The frontal lobe, not only fusiform gyrus, may play role in reading Hanja, although more evidence is needed.

Keyword

alexia; fusiform gyrus; ideogram; phonogram

MeSH Terms

Brain
Dyslexia*
Frontal Lobe
Humans
Magnetic Resonance Imaging*
Middle Aged
Parietal Lobe
Reading
Stroke*
Temporal Lobe*

Figure

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  Fig. 1 Diffusion weighted images (upper row) and corresponding FDG-PET CT images (lower row) revealed destructive lesions (white arrow) in the area of left frontal and left parietal lobe. FDG-PET: fluorodeoxyglucose-positron emission tomography.

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  Fig. 2 Language tasks presented as a bar chart at time of 2 weeks, 6 weeks and 6 months after the symptom onset. A: Total number of hits (correct) during the reading and writing of Hanja and Hangul. B: Mean response time for the same test.

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  Fig. 3 The activation areas for "Hanja reading" minus "baseline" (A) at 2 weeks and (B) at 6 months after the symptom onset (Threshold at p<0.001, uncorrected, cluster size >100).

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  Fig. 4 The middle frontal gyrus bilaterally showed greater activation after six months in parallel with Hanja reading improvement (Threshold at p<0.001, uncorrected, cluster size >100).

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