Medial-Vowel Writing Difficulty in Korean Syllabic Writing: A Characteristic Sign of Alzheimer's Disease

BACKGROUND AND PURPOSE: Korean-speaking patients with a brain injury may show agraphia that differs from that of English-speaking patients due to the unique features of Hangul syllabic writing. Each grapheme in Hangul must be arranged from left to right and/or top to bottom within a square space to form a syllable, which requires greater visuospatial abilities than when writing the letters constituting an alphabetic writing system. Among the Hangul grapheme positions within a syllable, the position of a vowel is important because it determines the writing direction and the whole configuration in Korean syllabic writing. Due to the visuospatial characteristics of the Hangul vowel, individuals with early-onset Alzheimer's disease (EOAD) may experiences differences between the difficulties of writing Hangul vowels and consonants due to prominent visuospatial dysfunctions caused by parietal lesions. METHODS: Eighteen patients with EOAD and 18 age-and-education-matched healthy adults participated in this study. The participants were requested to listen to and write 30 monosyllabic characters that consisted of an initial consonant, medial vowel, and final consonant with a one-to-one phoneme-to-grapheme correspondence. We measured the writing time for each grapheme, the pause time between writing the initial consonant and the medial vowel (P1), and the pause time between writing the medial vowel and the final consonant (P2). RESULTS: All grapheme writing and pause times were significantly longer in the EOAD group than in the controls. P1 was also significantly longer than P2 in the EOAD group. CONCLUSIONS: Patients with EOAD might require a higher judgment ability and longer processing time for determining the visuospatial grapheme position before writing medial vowels. This finding suggests that a longer pause time before writing medial vowels is an early marker of visuospatial dysfunction in patients with EOAD.

Neural Substrates of Hanja (Logogram) and Hangul (Phonogram) Character Readings by Functional Magnetic Resonance Imaging

The two basic scripts of the Korean writing system, Hanja (the logography of the traditional Korean character) and Hangul (the more newer Korean alphabet), have been used together since the 14th century. While Hanja character has its own morphemic base, Hangul being purely phonemic without morphemic base. These two, therefore, have substantially different outcomes as a language as well as different neural responses. Based on these linguistic differences between Hanja and Hangul, we have launched two studies; first was to find differences in cortical activation when it is stimulated by Hanja and Hangul reading to support the much discussed dual-route hypothesis of logographic and phonological routes in the brain by fMRI (Experiment 1). The second objective was to evaluate how Hanja and Hangul affect comprehension, therefore, recognition memory, specifically the effects of semantic transparency and morphemic clarity on memory consolidation and then related cortical activations, using functional magnetic resonance imaging (fMRI) (Experiment 2). The first fMRI experiment indicated relatively large areas of the brain are activated by Hanja reading compared to Hangul reading. The second experiment, the recognition memory study, revealed two findings, that is there is only a small difference in recognition memory for semantic transparency, while for the morphemic clarity was much larger between Hanja and Hangul. That is the morphemic clarity has significantly more effect than semantic transparency on recognition memory when studies by fMRI in correlation with behavioral study.

Effects of Night Sleep on Motor Learning Using Transcranial Magnetic Stimulation

OBJECTIVE: To investigate the effects of night sleep on motor cortical excitability with TMS (transcranial magnetic stimulation) and finger tapping performance. METHOD: Eight volunteers were enrolled to investigate the effects of day wake or night sleep on motor learning and finger performance. Each subject underwent a finger tapping task over a 12 hour period, which was employed to evaluate the motor cortical excitability affected by motor learning. Starting at 9:00 am for the day wake cycle and restarting at 9:00 pm for the night sleep cycle. The finger tapping task was the index finger of the non-dominant hand with the Hangul word personal computer (PC) training program. The data was assessed by comparing the changes observed with the cortical excitability and finger tapping performance tests between the day wake and night sleep after equivalent amounts of training. RESULTS: The results showed that in paired-pulse techniques, there was a significant decrease of intracortical inhibition (ICI) in the morning following the night sleep cycle (p<0.05), but no significant change was seen in the ICI in the evening for the day wake cycle. In addition a significant decrease of the ICI was observed in comparison to the morning following the night sleep cycle and the evening following the day wake cycle (p<0.05). The 140% recruitment curve (RC) and accuracy of the finger tapping performance demonstrated a significant improvement for both cycles (p<0.05). CONCLUSION: Through this study, we observed that the Hangul typing practice requires both explicit and implicit skill learning. And also the off-line learning during a night of sleep may be affected by an inhibitory neurotransmitter related synaptic plasticity and by the time dependent learning with recruitments of remote or less excitable motor neurons in the primary motor cortex.

Dissociation of Hangul and Hanja Reading After Left Parieto-occipital Infarction: Alexia with agraphia with Hangul, but preserved in Hanja

Korean vocabularies are composed of ideograms (Hanja) and phonograms (Hangle) just like Kanji (ideogram) and Kana (Phonogram) in Japanese. Double dissociation between the phonogram and ideogram has been reported in both languages. According to those studies, the ideograms are localized in more selective brain areas than the phonograms. We report on a case of alexia with agraphia for Hangle and intact reading for Hanja after a left parieto-occipital lobe infarction.

Common Mistakes in Preparing Manuscripts: Review of 21 Original Contributions

BACKGROUND: To analyze orthographic and regulatory mistakes in manuscripts contributed to the Journal of Korean Neurological Association (KNA), and thus to improve the quality of the articles. METHODS: Twenty-one original contributions written in Korean were reviewed and analyzed. They reached me from January to July in 2002 and were at the final editing stage just before being publicated. I analyzed their mistakes according to the Hangul orthographic guidelines and the contribution regulations of KNA. RESULTS: Among the total of 4,586 errors, 3,268 (71.3%) were ortho-graphic and 1,318 (28.7%) regulatory. Orthographic mistakes were mainly in the use of parentheses, selection of terms, and misspelling in the decreasing order. Violations of the contribution regulations were found mainly in tables, references, and figures rather than the body of the articles. CONCLUSIONS: Editorial Committee should make more efforts in the education of Hangul orthography for KNA members. And KNA members should pay particular attention to the mistakes in the orthographic and regulatory aspects to enhance the completeness of the articles.

Horizontal versus Vertical Reading in Neglect Dyslexia: A Case Study

BACKGROUND: Neglect dyslexia is a type of neglect syndrome, in which patients with unilateral hemisphere injury omit or misread the contralateral side of a text or the initial letters of a word. Hangul can be arrayed vertically (vertical reading, VR) as well as horizontally (horizontal reading, HR). Thus, HR and VR can be differentially affected in neglect dyslexia. We conducted an experiment in a 66 year-old woman who suffered from neglect dyslexia after a right cerebral infarction. We compared HR with VR in terms of error frequencies and patterns. METHODS: Stimuli for neglect dyslexia consisted of 227 words. The 227 words were written horizontally or vertically (total 554 words) and were pre-sented in random order. The patient was asked to read the words and the examiner recorded the patient's responses and reaction times. RESULTS: The differences in HR and VR were as follows: 1) the error frequency in HR (59.0%) was higher than the error frequency in VR (20.3%), 2) the most frequent error in HR was syllabic deletion (79.1%) whereas phonemic substitution (89.1%) predominated in VR, 3) the error rate was highest at the first syllabic position in HR whereas no position effect was noted in VR. CONCLUSIONS: Patients with neglect dyslexia make less error in VR than in HR. The neural processing of HR may be different from that of VR. VR may be an alternative reading strategy that may be useful during the recovery stage of neglect dyslexia.

Hanja Alexia with Agraphia After Left Posterior Inferior Temporal Lobe Infarction: A Case Study

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.

Use of Korean Letter "Hangul" and Special Characters in a Chromosome Image Analyzer, QuipsTM 3.0 Operable Only in Mac OS 8.0 / 대한임상병리학회지

BACKGROUND: Nowadays, many laboratories use computer and karyotyping software in chromosome analysis on the development of computer and digital imaging technology. And some of these softwares, such as QuipsTM (Vysis, USA; QuipsTM), are those operated in Macintosh operating system (Mac OS) because it had been considered superior to IBM PC in imaging works. However, Korean users have had difficulties in use of Korean letter "Hangul" because many of these hadn't been operated in Korean Macintosh System (KH series). METHODS: We used a karyotyping software of Macintosh QuipsTM 3.0, which is inconvenient to manage patient informations such as name, department, doctor's name and etc. In order to use "Hangul" in QuipsTM 3.0, we incorporated some files (WorldScript II and ScriptSwitcher 8 along with other files such as fonts, "Imrykki" and etc.) from KH 8.0 (Elex, Co; Korean Macintosh system) to Mac OS 8.0 (Apple, Inc; English Macintosh system). RESULTS: After modifing the operating system of Mac OS 8.0, we could use not only "Hangul", but also Chinese letter "Hanja" and special characters (e.g., "alpha", "-->", and etc). CONCLUSIONS: In using "Hangul" in data management and reporting, we became to be familiar with QuipsTM and had good responses from clinicians.