• Clinical and Experimental Pediatrics
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• v.49 no.4
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• pp.341-353
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• 2006

Learning disorders are diagnosed when the individual's achievement on standardized tests in reading, mathematics, or written expression is substantially below that expected for age, schooling, and level of intelligence. Subtypes of learning disorders may be classified into two groups, language-based type learning disorders including reading and writing disorder, and nonverbal type learning disorder (NLD) such as those relating to mathematics & visuospatial skills, and those in the autism spectrum. Converging evidence indicates that reading disorder represents a disorder within the language system and more specifically within a particular subcomponent of that system, phonological processing. Recent advances in neuroimaging technology, particularly the development of fMRI, provide evidences of a neurobiological basis for reading disorder, specifically a disruption of two left hemisphere posterior brain systems, one parieto-temporal, the other occipito-temporal. The former is the reading system for beginner reading, the latter for skilled reading. Compensatory engagement of anterior systems around the inferior frontal gyrus(Broca's area) and a posterior(right occipito-temporal) system is noted in persistent poor readers in long-term follow up study. The theoretical model proposed to explain NLD's source is not right hemisphere damage, but rather the white matter model. The working hypothesis of the white matter model is that the underdevelopment of, damage to, or dysfunction of cerebral white matter(long myelinated fibers) is the source of this disorder. The role of an evidence-based effective intervention in the remediation of children with learning disorder is discussed.

• Journal of Korean Neurosurgical Society
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• v.44 no.3
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• pp.159-162
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• 2008

Stenting is a useful alternative treatment modality in carotid artery stenosis patients who are too high-risk to undergo carotid endarterectomy (CEA). We report a case of contralateral cerebral infarction after stenting for extracranial carotid stenosis. A 78-year-old woman was admitted to the hospital with left-sided weakness. Based on magnetic resonance imaging (MRI) of the brain and conventional angiography, she was diagnosed with an acute watershed infarct of the right hemisphere secondary to severe carotid stenosis. Stenting was performed for treatment of the right carotid artery stenosis after a one-week cerebral angiogram was completed. Thirty minutes after stent placement, the patient exhibited a generalized seizure. Four hours later, brain MRI revealed left hemispheric cerebral infarction. Complex aorta-like arch elongation, tortuosity, calcification, and acute angulation at the origin of the supra-aortic arteries may increase the risk of procedural complications. In our case, we suggest that difficult carotid artery catheterization, with aggressive maneuvering during stenting, likely injured the tortuous, atherosclerotic aortic arch, and led to infarction of the contralateral cerebral hemisphere by thromboemboli formed on the wall of the atherosclerotic aorta.

• Clinical and Experimental Pediatrics
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• v.49 no.2
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• pp.208-211
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• 2006

Dyke-Davidoff-Masson Syndrome (DDMS) is a rare condition characterized by asymmetry of cerebral hemispheric growth with atrophy on one side, ipsilateral compensatory osseous hypertrophy, and contralateral hemiparesis. We experienced a 17 month-old male who presented with left focal clonic or tonic-clonic seizures accompanied by left hemiparesis and developmental delay. Brain MRIs demonstrated progressive atrophy of the right cerebral hemisphere with dilatation of the lateral ventricle, expansion of the ipsilateral frontal sinus with calvarial thickening, and elevation of the petrous pyramid and orbital roof. Brain SPECT showed a decreased volume of the right hemisphere with reduced blood flow. We therefore report a case of DDMS with a review of the literature.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.1707-1714
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• 2015

The neural bases underlying within or between-language picture naming was investigated by using event-related fMRI. The present suudy explorered the following two goals: The first is to compare cortical activation areas relevant to naming process in native and foreign language, and to decide whether the activation pattern of the foreign word will be the same as native words or not. The next is to find the cerebral areas involved only in alternating language switching between native and foreign language condition. Differential activation patterns were observed for language switching against one-language. Both naming tasks all activated the left inferior frontal gyrus (LIFG) as expected. However the differences in naming between languages were reflected in the activation amount of the LIFG, namely more activation in naming the native language than the foreign language. Especially, naming of the foreign word from English showed the similar area and size in activation with native language suggesting that the process of borrowed noun resembles that of native common noun. And the language switching between languages newly activated the right middle frontal gyrus as well as the left inferior frontal areas. The right middle frontal gyrus engagement in switching conditions obviously identified that right hemisphere is recruited in code switching possibly with respect to meta-cognition controlling language index at a subconscious level.

• Journal of Integrative Natural Science
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• v.11 no.3
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• pp.139-147
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• 2018

Hippocampal atrophy is a well-established imaging biomarker of Alzheimer disease (AD). However, hippocampus is a non-homogenous structure with cytoarchitecturally and functionally distinct sub-regions or subfield, with each region performing distinct functions. Certain regions of the subfield have shown selective vulnerability to AD. Here, we are interested in studying the effects of normal aging and mild cognitive impairment on these sub-regional volumes. With a reliable automated segmentation technique, we segmented these subregions of the hippocampus in 101 cognitively normal (CN), 135 early mild cognitive impairment (EMCI), 67 late mild cognitive impairment (LMCI) and 48 AD subjects. Thereby, dividing the hippocampus into hippocampal tail (tail), subiculum (SUB), cornu ammonis 1 (CA1), hippocampal fissure (fissure), presubiculum (PSUB), parasubiculum (ParaSUB), molecular layer (ML), granule cells/molecular layer/dentate gyrus (GCMLDG), cornu ammonis 3(CA3), cornu ammonis 4(CA4), fimbria and hippocampal-amygdala transition area (HATA). In this cross sectional study of 351 ADNI subjects, no differences in terms of age, gender, and years of education were observed among the groups. Though, the groups had statistically significant differences (p < 0.05 after the multiple comparison correction) in the Mini-Mental State Examination (MMSE) scores. There was asymmetrical volume loss in the early stages of AD with the left hemisphere showing volume loss in regions that were unaffected in the right hemisphere. Bilateral parasubiculum, right cornu ammonis 1, 3 and 4, right fimbria and right HATA regions did not show any volume loss till the late MCI stages. Our findings suggest that the hippocampal subfield regions are selectively vulnerable to AD and also that these vulnerabilities are asymmetrical especially during the early stages of AD.

• The Journal of Korean Physical Therapy
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• v.17 no.2
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• pp.67-87
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• 2005

Impaired sensorimotor function of the hand ipsilateral to a unilateral brain damage has been reported in a variety of motor task. however, it is still the controversial issue because of the difficulty of detection in clinical situation, patients' variability(time after onset, contralateral upper extremity severity, other cognitive functions including apraxia), and the performed various motor task. The purpose of this study is to determine the presence of ipsilateral motor deficit following unilateral brain damage in three different specific tasks(hand tapping, visual tracking and coin rotation) compared with healthy age-sex matched control group using the same hand and to investigate the lateralized motor control in each hemispheric function. Findings revealed that stroke patients with unilateral brain damage experienced difficulties with rapid-simple repetitive movement, visuomotor coordination, complex sequencing movement on ipsilateral side. Also, Comparison of the left-hemispheric stroke groups and the right-hemispheric stroke groups revealed that patients with a left-hemisphere damage tended to be more variable in performing all of the three tasks. These results show that stroke patient with left hemisphere damage has more ipsilateral motor deficit, and the left hemisphere contributes to the processing of motor control that necessary for the executing actions with ipsilateral hand.

• Investigative Magnetic Resonance Imaging
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• v.4 no.1
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• pp.14-19
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• 2000

Purpose : This study was to present the functional brain mapping of both functional magnetic resonance imaging(MRI) and transcranial magnetic stimulation(TMS) in a case of schizencephaly. Materials and methods : A 28-year-old man, who had left hemiplegia and schizencephaly in right cerebral hemisphere, was exacted with both functional MRI and TMS. Motor function of left hand was decreased whereas right hand was within normal limit. For functional MRI, gradient-echo echo planar imaging($TR/TE/{\alpha}$=1.2 sec/90 msec/90) was employed. The paradigm of motor task consisted of repetitive self-paseo hand flexion-extension exercises with 1-2 Hz periods. An image set of 10 slices was repetitively acquired with 15 seconds alternating periods of task performance and rest and total 6 cycles (three ON periods and three OFF periods) were performed. In brain mapping, TMS was performed with the round magnetic stimulator (mean diameter; 90mm). The magnetic stimulation was done with 80% of maximal output. The latency and amplitude of motor evoked potential(MEP)s were obtained from both abductor pollicis brevis(APB) muscles. Results : Functional MRI revealed activation of the left primary motor cortex with flexion-extension exercises of healthy right hand. On the other hand, the left primary motor cortex, left supplementary motor cortex, and left promoter areas were activated with flexion-extension exercises of left hand. In TMS, magnetic evoked potentials were induced in no areas of right cerebral hemisphere, but in 5 areas of left corebral hemisphere from both abductor pollicis brevis. Latency, amplitude, and contour of response of the magnetic evoked potentials in both hands were similar. Conclusion : Functional MRI and TMS in a patient with schizencephaly were successfully used to localize cortical motor function. Ipsilateral motor pathway is thought to be secondary to reinforcement of the corticospinal tract of the ipsilateral motor cortex.

• Journal of Korean Neurosurgical Society
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• v.57 no.2
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• pp.127-130
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• 2015

A 59-year-old female presented with progressive right proptosis, chemosis and ocular pain. An imaging work-up including conventional catheter angiography showed a right-sided dural arteriovenous fistula of the cavernous sinus, which drained into the right superior petrosal sinus, right superior ophthalmic vein, and right inferior ophthalmic vein, and cortical venous reflux was seen via the right petrosal vein in the right posterior fossa. After failure of transvenous embolization, the patient underwent Gamma Knife radiosurgery (GKRS). At one month after GKRS, she developed increasing ocular pain and occipital headache. Repeat angiography showed partial obliteration of the fistula and loss of drainage via the superior and inferior ophthalmic veins with severe congestion, resulting in slow flow around the right cerebellar hemisphere. Prompt transarterial embolization relieved the patient's ocular symptoms and headache. We report on a case of paradoxical exacerbation of symptoms resulting from obstruction of the venous outflow after GKRS for treatment of a dural arteriovenous fistula of the cavernous sinus.

• Journal of Korea Multimedia Society
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• v.19 no.8
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• pp.1260-1274
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• 2016

To obtain good summarization algorithms, we need first understand how people summarize videos. 'Semantic gap' refers to the gap between semantics implied in video summarization algorithms and what people actually infer from watching videos. We hypothesized that ERP responses to real time videos will show either N400 effects to topic-irrelevant shots in the 300∼500ms time-range after stimulus on-set or P600 effects to topic-relevant shots in the 500∼700ms time range. We recruited 32 participants in the EEG experiment, asking them to focus on the topic of short videos and to memorize relevant shots to the topic of the video. After analysing real time videos based on the participants' rating information, we obtained the following t-test result, showing N400 effects on PF1, F7, F3, C3, Cz, T7, and FT7 positions on the left and central hemisphere, and P600 effects on PF1, C3, Cz, and FCz on the left and central hemisphere and C4, FC4, P8, and TP8 on the right. A further 3-way MANOVA test with repeated measures of topic-relevance, hemisphere, and electrode positions showed significant interaction effects, implying that the left hemisphere at central, frontal, and pre-frontal positions were sensitive in detecting topic-relevant shots while watching real time videos.

• Science of Emotion and Sensibility
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• v.8 no.1
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• pp.55-61
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• 2005

The purpose of the study was to examine any difference in academic achievement, self-concept and achievement motivation by the types of hemispheric dominance. 189 high school students participated in the study. They were taken three kinds of different psychological tests i.e., the brain hemispheric preference (dominance), the self-concept and the achievement motivation tests. Three types of hemispheric dominance were classified as the left hemispheric, the right hemispheric and whole brain dominances. The results showed that students with the right hemispheric dominance showed lower academic achievement and self concept than the other groups students. Those who had left hemisphere dominance showed higher achievement motivation than the right hemispheric students. These results could be interpreted that education in the high school in Korea mainly focuses left hemisphere related topics or subjects.