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.
Subject(s)
Humans , Middle Aged , Brain , Dyslexia , Frontal Lobe , Magnetic Resonance Imaging , Parietal Lobe , Reading , Stroke , Temporal LobeABSTRACT
Korean written language is composed of ideogram (Hanja) and phonogram (Hangul), as Japanese consists of Kanji (ideogram) and Kana (phonogram). Dissociation between ideogram and phonogram impairment after brain injury has been reported in Japanese, but few in Korean. We report a 64-yr-old right-handed man who showed alexia with agraphia in Hanja but preserved Hangul reading and writing after a left posterior inferior temporal lobe infarction. Interestingly, the patient was an expert in Hanja; he had been a Hanja calligrapher over 40 yr. However, when presented with 65 basic Chinese letters that are taught in elementary school, his responses were slow both in reading (6.3 sec/letter) and writing (8.8 sec/letter). The rate of correct response was 81.5% (53 out of 65 letters) both in reading and writing. The patient's performances were beyond mean-2SD of those of six age-, sex-, and education-matched controls who correctly read 64.7 out of 65 and wrote 62.5 out of 65 letters with a much shorter reaction time (1.3 sec/letter for reading and 4.0 sec/letter for writing). These findings support the notion that ideogram and phonogram can be mediated in different brain regions and Hanja alexia with agraphia in Korean patients can be associated with a left posterior inferior temporal lesion.