• Annals of Clinical Neurophysiology
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• v.7 no.2
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• pp.93-96
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• 2005

Background: Myasthenia gravis (MG) and systemic lupus erythematosus (SLE) are well recognized to coexist and have some similarities in immunologic, clinical and serologic findings. Despite several reports of the association with autoantibodies and thymectomy in these disorders, the pathomechanism of coexistence remains to be elucidated. Objective: We aimed to investigate the relationship of MG and SLE through overall features of patients with both disorders;: clinical, laboratory, and electrophysiological findings. Materials and Methods: We reviewed the medical records of 6 consecutive patients with MG and SLE (2 men, 4 women, ages 17-51, mean 30.5 years, Seoul National University Hospital, from 1998 to 2005). Results: Three patients who developed SLE first, had ocular type of MG and 2 were children showing much severe and recurrent SLE features and only 1 patient had thymic hyperplasia. The other 3 developed MG first and they were generalized type and none underwent thymectomy. In addition, the development of MG or SLE was not coincident with remission or improvement of another disorder. Conclusion: The coexistence of SLE and MG may support the hypothesis of two different antibody populations modulated by thymus in the opposite extremesThis report suggests that the systemic and extensive autoimmune response in preceding MG or SLE may effect the development of the other disorder followed, while. the coexistence of two disorders cannot be explained by the hypothesis of two different antibody populations modulated by thymus in the opposite extremes The role of thymectomy and the theorectical subsequent effect on the development of SLE have been debated with controversy. However, SLE occurred without thymectomy in MG and these disorders did not develop in the quiescent period of another disorder. Therefore, the other pathomechanism for the coexistence of MG and SLE should be elucidated.

• Annals of Clinical Neurophysiology
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• v.4 no.2
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• pp.125-132
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• 2002

Objectives : Although the diagnosis of hereditary neuropathy with liability to pressure palsies (HNPP) is important for correct prognostic evaluation and genetic counseling, the diagnosis is frequently missed or delayed. Our main aim on undertaking this study was to characterize the electrodiagnostic features of HNPP. Material and Methods : Clinical, electrophysiologic and molecular studies were performed on Korean HNPP patients with 17p11.2 deletion. The results of electrophysiologic studies were compared with those of Charcot-Marie-Tooth disease type 1A (CMT1A) patients carrying 17p11.2 duplication. Results : Eight HNPP (50 motor, 39 sensory nerves) and six CMT1A (28 motor, 16 sensory nerves) patients were included. The slowing of sensory conduction in nearly all nerves and the distal accentuation of motor conduction abnormalities are the main features of background polyneuropathy in HNPP. In contrast to CMT1A, where severity of nerve conduction slowing was not different among nerve groups, HNPP sensory nerve conduction was more slowed in the median and ulnar nerves than in the sural nerve (p<0.01), and DML was more prolonged in the median nerve than in the other motor nerves (p<0.01). TLIs were significantly lower in HNPP than in the normal control and CMT1A patients for the median and ulnar nerves (p<0.01), and were also significantly reduced for the peroneal nerve (p<0.05) compared with those of the normal controls. Conclusion : The distribution and severity of the background electrophysiologic abnormalities are closely related to the topography of common entrapment or compression sites, which suggests the possible pathogenetic role of subclinical pressure injury at these sites in the development of the distinct background polyneuropathy in HNPP.

• The Journal of the Acoustical Society of Korea
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• v.35 no.1
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• pp.63-73
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• 2016

It is widely acknowledged that the human auditory system is organized tonotopically and people generally listen to sounds as a function of frequency distribution through the auditory system. However, it is still unclear how acoustic features of speech sounds are indicated to the human brain in terms of speech perception. Thus, the purpose of this study is to investigate whether two sounds with similar high-frequency characteristics in the acoustic analysis show similar results at the level of auditory brainstem. Thirty three young adults with normal hearing participated in the study. As stimuli, two Korean monosyllables (i.e., /ja/ and /cha/) and four frequencies of toneburst (i.e., 500, 1000, 2000, and 4000 Hz) were used to elicit the auditory brainstem response (ABR). Measures of monosyllable and toneburst were highly replicable and the wave V of waveform was detectable in all subjects. In the results of Pearson correlation analysis, the /ja/ syllable had a high correlation with 4000 Hz of toneburst which means that its acoustic characteristics (i.e., 3671~5384 Hz) showed the same results in the brainstem. However, the /cha/ syllable had a high correlation with 1000 and 2000 Hz of toneburst although it has acoustical distribution of 3362~5412 Hz. We concluded that there was disagreement between acoustic features and physiology outcomes at the auditory brainstem level. This finding suggests that an acoustical-perceptual mapping study is needed to scrutinize human speech perception.

• Annals of Clinical Neurophysiology
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• v.14 no.1
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• pp.29-35
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• 2012

Background: Peripheral neuropathy is the most frequent neurological complication in human immunodeficiency virus (HIV) infection, related with diverse etiologies including inflammation, opportunistic infection and side effects of medications. The purpose of the present study was to evaluate characteristics of HIV associated neuropathy according to the stage of HIV infection. Methods: In reviewing the medical records of HIV patients who underwent electrodiagnostic studies between 1997 and 2011, total 11 patients (all males; median age, 47 years; range, 28-71 years) with comorbid neuropathy were enrolled. Stage of HIV infection was categorized according to the Centers for Disease Control and Prevention (CDC) criteria. Classification of peripheral neuropathy was based on clinical and electrophysiological features. Results: Distal symmetric polyneuropathy was observed in 8 patients (72.7%), inflammatory demyelinating polyneuropathy in 2 patients (18.1%), and polyradiculopathy in 1 patient (9.1%). Median CD4+ T cell count was $123/mm^3$ (range, $8-540/mm^3$) and 7 patients (60%) had the most advanced HIV disease stage (CDC-C3). There was no neuropathy caused by CMV infection. Conclusions: Distal symmetric polyneuropathy was the most common type of neuropathy in HIV infection, but various forms of neuropathy such as inflammatory demyelinating polyneuropathy and polyradiculopathy were also present. HIV associated neuropathy is more frequently associated with advancing immunosuppression, although it can occur in all stages of HIV infection.

• Journal of Korean Neurosurgical Society
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• v.29 no.11
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• pp.1429-1436
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• 2000

Objectives : This study was performed in cultured rat hippocampal neurons to investigate the acute electrophysiological features of ionotropic glutamate receptors which act as a major excitatory neurotransmitter in mammalian brain. Method : Glutamate receptor agonists were applied into the bath solution embedding in whole-cell patch-clamp recording of single hippocampal neuron. Results : In voltage-clamped at -60mV and the presence of 1mmol $Mg^{2+}$, extracellulary applied NMDA did not induce any inward current. Both the elimination of $Mg^{2+}$ and addition of glycine in bath, however, elicited a NMDAinduced inward current. $Mg^{2+}$ block current was increased gradually in more negative potentials from -30mV, showing a negative slope in I-V plot with $Mg^{2+}$. Glutamate-induced current represented an outward rectification. A non-NMDA receptor component occupied about 40% of glutamate-induced current in the voltage range of -80mV to +60mV. Conclusion : Present study suggests that glutamate activates acutely the non-NMDA receptors which induces an inward current in the level of resting membrane potential. This makes the membrane potential increase and can activate the NMDA receptors that permit calcium influx against $Mg^{2+}$ block. At the depolarized state of neuron, there may be recovery mechanisms of membrane potential to repolarize irrespective of voltage-dependent potassium channels in the hippocampal neurons.

• Journal of Yeungnam Medical Science
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• v.16 no.1
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• pp.125-130
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• 1999

Congenital myotonia is a hereditary disorder of the skeletal muscle. The most characteristic features of the disease are myotonia and variable muscular hypertrophy. Molecular biologic investigations have revealed that mutations in the gene of the human skeletal muscle chloride ion channel protein are a cause of the disease. The Becker's type congenial myotonia is clinically similar to the autosomal dominantly inherited congenital myotonia (Thomsen's disease). Both disorders are characterized electrophysiologically by increased excitability of muscle fibers. reflected in clinical myotonia. In general, Becker's type congenital myotonia is more severe than Thomsen's disease in muscular hypertrophy and weakness. The authors recently experienced a 25-year-old female patient who has no family-related disease history and who has conspicuous muscular hypertrophy and the stiffness with muscles which occurred from the age of 3 or 4. Clinically she showed the authors a percussion myotonia. On electrophysiological study, exercise and repetitive stimulation of the abductor digiti quinti muscle disclosed a decline in the compound muscle action potential. Biopsy of biceps muscle revealed enlargement of muscle fibers with marked nuclear internalization. After the oral taking the Mexiletine, the patient showed a favorable turn a little with her stiffness of muscles. So we authors are reporting one case of Becker's type congenital myotonia with review of literatures.

• Journal of Korean Neurosurgical Society
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• v.53 no.1
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• pp.1-5
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• 2013

Objective : The purpose of this study was to evaluate the characteristics and surgical outcomes of familial hemifacial spasm (HFS) and to discuss the role of genetic susceptibility. Methods : Between 2001 and 2011, 20 familial HFS patients with ten different pedigrees visited our hospital. The data from comprehensive evaluation of these patients, including clinical, radiological and electrophysiological data and surgical outcomes were reviewed to characterize familial HFS and to compare the characteristics between familial HFS and sporadic HFS. Results : According to the family tree, the inheritance pattern was difficult to define clearly using these data. Radiologic findings suggested that the vertebral artery (VA) was a more frequent offender in familial HFS than in sporadic cases (35.0% vs. 10.0%, p<0.001). Chi-square test showed that there were no correlation between VA tortuosity and underlying morbidity such as diabetes or hypertension (p=0.391). Eighteen out of 19 patients who underwent microvascular decompression showed no residual spasm. Other features of familial HFS overlap with sporadic cases. These findings suggest that certain genetic susceptibilities rather than hypertension or diabetes may influence vascular tortuosity and HFS development. Conclusion : In this study, familial HFS seems not so different from sporadic cases. Authors thought familial HFS could have heterogeneous etiology. Further study of familial HFS including clinical, anatomic, genetic, and molecular information may help identify a gene or trait that can provide insight into the mechanisms of sporadic and familial HFS.

• Annals of Clinical Neurophysiology
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• v.7 no.1
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• pp.7-12
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• 2005

Background: Essential tremor (ET) is a common movement disorder that often causes functional disability. There have been very few investigations about the clinical characteristics of ET in Korea. Therefore, we performed a study showing the clinical features and electrophysiological findings of ET. Methods: We analyzed medical records and accelerometry data of 152 patients (male vs female; 79 vs 73) with ET, who visited the Neurology Clinic of Hospital from 2000 to 2003. Clinical characteristics of ET were summarized including the age of onset, family history, tremor type, body part involved, and associated symptoms. The frequency of tremor was recorded and the spectral analysis of tremor was performed. Results: The age of tremor onset showed bimodal distribution with peaks in the 2nd and 5th decades. Family history was found in 46 patients (30.3%). The patients with the family history presented earlier onset of tremor than patients without the history (mean age of onset, y: 35.2 vs. 49.9, P < 0.001). Tremor appeared most frequently in hands (94%), and followed by head (25%). In head tremor, "no-no" pattern was mainly observed and the head tremor was more frequently observed in female. The frequency of tremor was negatively correlated with age (r=-0.49, P<0.001). Conclusions: The present study indicated some important findings about ET: (1) bimodal distribution for an age of onset, (2) younger age of onset in patients with a family history, (3) decreasing frequency of the tremor according to age, and (4) higher prevalence of head tremor in female patients.

• Proceedings of the Korean Biophysical Society Conference
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• 2003.06a
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• pp.42-42
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• 2003

Large-conductance $Ca^{2+}$-activated potassium channels ($BK_{Ca}$ are a widely distributed and play key roles in various cell functions. In nerve cells, $BK_{Ca}$ channels shorten the duration of action potentials and block $Ca^{2+}$ entry thereby repolarizing excitable cells after excitation. $BK_{Ca}$ channel opening has been postulated to confer neuroprotection during stroke, and has attracted attention as a means for therapeutic intervention in asthma, hypertension, convulsions, and traumatic brain injury. Several natural and synthetic compounds including a steroid hormone, $\beta$-estradiol, have been identified as the activators of $BK_{Ca}$ channels. Based on the structural features of the previously reported activators of $BK_{Ca}$ channels, we designed several lead compounds, synthesized chemically, and tested their functional activity on cloned $BK_{Ca}$ channels. The $\alpha$ subunit of rat $BK_{Ca}$ channel was expressed alone or with different $\beta$ subunits in Xenopus oocytes and the effects of the compounds were tested electrophysiological means. One of the lead compounds affected the activity of the $\alpha$ subunit of $BK_{Ca}$ channel in a $\beta$ subunit-specific manner. While the activity of B $K_{ca}$ channel $\alpha$ subunit was Potentiated, the channel composed of $\alpha$ and $\beta$1 subunits were inhibited by this compound. We are currently investigating the mechanism of the $\beta$ subunit-dependent effects and planning to localize the receptor site of the lead compound.f the lead compound.

• Annals of Clinical Neurophysiology
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• v.3 no.2
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• pp.128-135
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• 2001

Background : Tremor is uncommon manifestation of stroke. Therefore a few cases have been reported until now. There is still uncertainty about the characteristics of post-stroke tremor. Furthermore the pathogenesis and responsible structures of post-stroke tremor are not precisely known. We have recently experienced 34 cases of post-stroke tremor for the past 6 years. We analysed the clinical features and electrophysiologic findings of post-stroke tremor to evaluate the general characteristics and to analogize the possible pathogenetic mechanisms of post-stroke tremor. Methods : The clinical characteristics of post-stroke tremor were summarized in according to the onset time, involved body parts, types, tremor frequencies, neuroradiologic findings, and associated symptoms. The tremor frequencies were recorded by using a gyroscope. The spectral analysis of tremor frequencies were done automatically with Motus I soft ware. Results : Tremor onset were remarkably varied. Some patients showed a tremor appearing at the onset of a stroke and other patients showed delayed-onset tremor 10 years after a stroke. Tremor frequencies were also much varied. The range of hand tremor frequencies were from 1.5 to 12 Hz. Lesions were found in 31 cases(infarction 27, hemorrhage 4) on neuroimaging. In the cases of cerebral infarctions, 7 cases showed multiple small vessel diseases and 20 cases showed cerebral vessel lesions. The most commonly involved cerebral vessel lesion was the middle cerebral artery territory Several different clinical patterns of post-stroke tremor were identified. Conclusions : There are some evidences from the data summarized here to suggest that several pathogenetic mechanisms including central oscillators could be involved for the development of tremors and that tremor generating neural circuits could be more complex than previously suggested neural circuits.