Intraexaminer Variability of Nerve Conduction Study in Healthy Person

BACKGROUND: Nerve conduction study (NCS) is an objective and quantitative test in evaluating peripheral nerve disorders. Several physiological and technical factors are well known to influence the results of NCS, which can be controlled and regulated by standardization of environment and through the process to make range of normality. However, most electromyographers do not pay much attentions about inter- and intra-examiner variabilities, and there are only a few and incomplete reports on these topics. We examined the intra-examiner variability of NCS on the basis of periods of practice. METHODS: Twenty-eight electromyographers were divided into two groups: residents and neurologist-technicians. All, having variable NCS training periods, have performed NCS on one of other 27 electromyographers ten times within two weeks where each study was made once a day. RESULTS: Coefficient of variation and external quotient increased according to the following order - nerve conduction velocities (NCV), terminal latencies (TL), and amplitudes of compound action potentials (AMP). There were significant differences between the two groups in NCV and TL, but no statistical difference in AMP. CONCLUSIONS: Our results suggest that errors from intra-examiner variability should be considered when interpreting NCS and that those electromyographers who have enough training should perform NCS.

The Influence of Acute Cerebral Infarction on the Circadian Rhythm of Melatonin Secretion

BACKGROUND: The circadian rhythm of circulating melatonin is regulated by the endogenous oscillators, the suprachi-asmatic nuclei, and entrained by the light-dark cycle of the environment, but it seems that the rhythm can be affected by variable lesions outside the retina-pineal pathway. We intended to know how acute cerebral infarction affects on the cir-cadian rhythm of plasma melatonin secretion. METHODS: Plasma melatonin level was measured from 64 patients with acute cerebral infarction. On admission, blood samples were collected by venipuncture at 2AM, 4AM, 10AM, and 2PM and melatonin level was measured by radioimmunoassay. The state of consciousness of each patient was assessed clini-cally and the infarction site and size were evaluated clinically and radiographically. RESULTS: Among 64 patients with acute cerebral infarction, dramatic blunting or obliteration of nocturnal melatonin surge in the blood was found in 29 patients. The circadian rhythm of melatonin secretion was absent in 12 of 35 alert patients, in 10 of 20 drowsy patients, and in 5 of 7 stuporous patients. Melatonin secretion into plasma was markedly decreased in all 2 comatose patients. Of 14 patients with brainstem lesions, 8 patients showed decreased melatonin levels with the absence of a nocturnal rise, although most of them were alert. CONCLUSIONS: This study suggests that brainstem and the initial mental state might contribute to the regulation of the circadian rhythm of plasma melatonin even though the lesion does not involve the retina-pineal pathway, but further extensive study is required to elucidate it. (J Korean Neurol Assoc 19(4):359~363, 2001)

The central conduction time in posterior tibial and pudendal nerve somatosensory evoked potentials

The somatosensory evoked potentials (SEPs), following stimulation of both the posterior tibial nerve (PTSEP) and pudendal nerve (PNSEP), comprise of the lumbar negative, subcortical and cortical potential. These can be used to assess the long somatosensory pathway, including peripheral, intraspinal and intracranial conduction along the entire length. This study aimed to compare the central conduction time between the PTSEP and the PNSEP, and to investigate the relationship between the intraspinal and intracranial conduction time in the SEP pathway. The SEPs following stimulation of the posterior tibial nerve at the ankle and the pudendal nerve at the shaft of the penis were analyzed in 20 normal male subjects. The central conduction of the PNSEP was found to be slower than that of the PTSEP (p <0.05). This difference is due to a delay in conduction rather than that of intracranial conduction.

Two Cases of Histiocytic Necrotizing Lymphadenitis Accompanied by Aseptic Meningitis

Histiocytic necrotizing lymphadenitis is a benign disorder of the lymph node which should be differentiated from other types of lymphadenitis or malignant lymphoma. The most common presentation includes fever and cervical lym-phadenopathy .The course is invariably benign and spontaneous resolution usually occurs within 4 to 6 months. The diagnosis is confirmed by characteristic pathological findings of the involved lymph node. The involvement of the ner-vous system is known to be rare. We report two patients with histiocytic necrotizing lymphadenitis accompanied by aseptic meningitis. In one patient, both diseases developed simultaneously and in the other patient, histiocytic necrotiz-ing lymphadenitis was followed by aseptic meningitis 2 months later.

A Case of Cerebral Infarction and Chronic Subdural Hematoma in Essential Thrombocythemia

Essential thrombocythemia is one type of the related chronic myeloproliferative disorders that also include poly-cythemia vera, chronic myelogenous leukemia, and idiopathic myelofibrosis. It is a rare disorder of unknown origin characterized by thrombocytosis, excessive megakaryocytes, hemorrhage, and thrombotic complication. Several cases of ischemic stroke in essential thrombocythemia have been reported, but cerebral infarction combined with cerebral hemorrhage has been very rare and has not been reported in Korea. We report a case of cerebral infarction and chronic subdural hematoma in a pateint with essential thrombocythemia. A 59-year-old woman with essential thrombocythemia was admitted with mild left hemiparesis that developed 3 days prior. She had a history of minor trauma 15 days prior. A brain MRI showed an infarction in the right temporal lobe and a chronic subdural hematoma in the right frontoparietal area. A cerebral angiography revealed an occlusion of the M2 portion of the right middle cerebral artery.

Spontaneous Resolution of Spinal Epidural Hematoma

Spontaneous spinal epidural hematoma is an uncommon cause of acute non-traumatic myelopathy and usually requires surgical evacuation. The typical clinical presentation is that of sudden and severe neck or back pain followed by progressive motor, sensory, and sphincteric disturbances within minutes to hours. Although many cases are idio-pathic, common causes include anticoagulant therapy, coagulopathies, hypertension, and vascular malformations. Magnetic resonance imaging (MRI) has become the primary method for diagnosis and follow-up. Prompt neurosurgical treatment with decompressive laminectomy has been regarded as the general method for neurological recovery, although rare cases of spontaneous recovery have been reported. We report such a case of spontaneous cervical spinal epidural hematoma that showed complete spontaneous resolution.

Clinical analysis of 12 Korean Lambert-Eaton myasthenic syndrome (LEMS) patients

The Lambert-Eaton myasthenic syndrome (LEMS) heralds the occurrence of malignancy, especially small-cell lung cancer (SCLC), but it can also occur in the absence of cancer. Twelve patients were diagnosed as LEMS by clinical features and the classical electrophysiological triad, which includes a low amplitude of compound muscle action potentials (CMAP), decremental responses on low-rate stimulation, and incremental responses on high-rate stimulation on the repetitive nerve stimulation (RNS) test. There were 6 male and 6 female patients, ranging in age from 49 to 66 years. Malignancy(all were SCLC) was found in 7 patients. Males predominantly expressed the paraneoplastic form; whereas the primary autoimmune form was found only in women, who showed a good response to corticosteroid treatment. The neurological features were similar in both groups: proximal lower limb weakness, depressed muscle stretch reflexes, and dryness of mouth in nearly all patients. Bulbar dysfunction and limb paresthesia were a little more frequent in the paraneoplastic form. In RNS tests, the characteristic electrophysiological abnormalities were found in all patients and were more profound in the paraneoplastic form. We concluded that LEMS is commonly associated with malignancy, especially SCLC, but it should also be stressed that there are many female LEMS patients who do not harbor any malignancy at all, and that other treatment strategies such as immunotherapy should be considered for these patients.

Subclinical Ulnar Neuropathy in Carpal Tunnel Syndrome

BACKGROUND: When performing routine diagnostic nerve conduction studies in patients with carpal tunnel syndrome(CTS), we sometimes happen to be confronted with patients who have also ulnar nerve abnormality without any clinical symptoms or signs, although not so common. Anatomically, the borders of the carpal tunnel and the Guyon canal share common features, separated from each other by the pisiform bone, and the volar carpal ligament forming both the roof of the carpal tunnel and the floor of the Guyon canal. Therefore, if there is an entrapment syndrome at the carpal tunnel with subsequent electrophysiological changes for the median nerve, the same process could also affect the ulnar nerve in the Guyon canal. METHODS: We analyzed 283 patients who were diagnosed as CTS clinically and electrophysiologically for the past 5 years in this hospital. RESULTS: Of 283 patients(491 hands) with CTS, 15 patients(16 hands) had ulnar nerve involvement(5%). Of 75 patients with unilateral CTS, 2 patients(2%) had ulnar nerve involvement; whereas of 208 patients with bilateral CTS, 13 patients(6%) had ulnar nerve involvement. CONCLUSIONS: This study cannot conclusively explain why there is involvement of the ulnar nerve in CTS, but ulnar nerve may be involved at the level of the Guyon canal in some patients with CTS as an entrapment phenomenon and the patients with bilateral CTS may have a more tendency to have ulnar nerve lesion than those with unilateral CTS. In patients with CTS, it would be better to check up if there is also ulnar nerve involvement.

A Case of Moyamoya Disease Associated with Complete Duplication of the Basilar artery

Moyamoya disease is characterized by a bilateral progressive narrowing of the distal internal carotid and proximal portions of the anterior and middle cerebral arteries. The cerebral vessels of the 11 to 14 mm embryonic period are extremely similar to these moyamoya vessels. The vertebral arteries unite with a contralateral homologue to form the basilar artery during embryonic development and rarely, the failure of complete fusion results in duplication of these arteries. It is well known that moyamoya disease sometimes is accompanied by persistent primitive arteries, cerebral aneurysm, or rarely arteriovenous malformation. However, no case of the moyamoya disease with complete duplication of basilar artery has been previously reported. These two types of vascular abnormality are probably associated in certain developmental period, and moyamoya disease causes hemodynamic load in the basilar artery system as a collateral pathway and these effects are also involved in duplication of basilar artery. The relationship between these two varieties of vascular abnormality and possible pathogenesis of the moyamoya disease are discussed.

Cerebrovascular Diseases in Cancer Patients

BACKGROUND: The association of vascular thrombosis with cancer has been known since Trousseau's description of venous thrombophlebitis in patients with carcinoma. Previous studies, mainly autopsy-based, have suggested that the stroke spectrum in cancer patients differ from that of the general population. However, no studies that address this question in the adult oncological population from a clinical perspective are available in Korea. We therefore assessed the clinical features of cerebrovascular diseases in cancer patients. METHODS: We retrospectively analyzed 44 cases of symptomatic cerebrovascular disease in cancer patients who were admitted to the Wonju Christian Hospital from January 1993 to June 1998 by reviewing their charts and brain CT or MRI; primary cancer, the interval from a cancer diagnosis to the occurrence of stroke, the incidence of hypercoagulability as an infarction cause, the location and size of the infarction, the type of hemorrhage, and the prognosis. RESULTS: The mean age was 62.3 years. Twenty eight cases (63.6%) were ischemic stroke and sixteen cases (36.4%) were hemorrhagic stroke. The most common primary cancer of infarction and hemorrhage was stomach cancer. In ischemic patients, the most common cell type of cancer was ade-nocarcinoma and six cases (21.4%) were considered to have hypercoagulability as a cause. In hemorrhagic patients, seventy percent of patients with coagulopathy died in the hospital or were discharged moribundly. CONCLUSIONS: Although hypercoagulability is present to a greater extent in the patient population than in the general population, it appears that conventional stroke risk factors account for the majority of cerebral ischemic events in the adult cancer population. Cancer patients with intracranial hemorrhage owing to coagulopathy reveal poor prognosis.

Clinical Significance of CTG Repeat Expansion in Korean Myotonic Dystrophy Patients

BACKGROUND: Myotonic dystrophy is the most common type of muscular dystrophy affecting adults, associated with the expansion of triplet repeat DNA sequences. A hallmark of the inherited disease with trinucleotide repeat DNA expansion is the clinical and genetic anticipation. The copy numbers of the CTG repeat are known to be related to the severity and the onset age of clinical symptoms. METHODS: The copy numbers of the CTG repeats were determined using PCR amplification and Southern blotting. The clinical manisfestations of 34 patients from 14 families who had the CTG repeat expansion were evaluated based on the muscular disability rating scale and the electrophysiological study. RESULTS: There was a significant positive correlation between the clinical scores and the size of the amplification of trinucleotide repeat, and a negative correlation with the age of onset. In 9 patients with copy numbers of CTG repeats between 61 and 100, 8 cases were asymptomatic and myotonic discharges were not seen in 71% of patients. Larger expanded bands, earlier onset, and worse symptoms were evident with each successive generation. CONCLUSIONS: Molecular genetic analysis with CTG repeat expansion might be useful in the detection and the genetic counseling of myotonic dystrophy patients.

A Comparative Trial of Oral and Subcutaneous Sumatriptan in Acute Treatment of Migraine: a multicenter trial

BACKGROUND: The efficacy of sumatriptan(SMN) in acute management of migrane has been well established. In Korea, however, a clinical study comparing the utility of oral(PO) and subcutaneous(SQ) regimen had not been conducted yet. This study was directed to compare the two regimens of SMN in terms of the efficacy as well as the adverse events in a singed-out Korea patient group. METHODS: The 91 migrane patients were recruited and randomly assigned to either PO or SQ regimen as the initial treatment of acute migrane attack. Then, they were forwarded to the other regimen as an open cross-over trial. The treatment responses and adverse events were assessed and rated by the subjects. RESULTS: Eighty one patient successfully tried at least one regimen of SMN. Overall, the proportion of excellent treatment response was 90.7%(PO) and 94.1%(SQ), with the occurrence of adverse events being 67.4%(PO) and 76.5%(SQ) respectively. In 18 patients who were able to complete cross-over procedure, the efficacy was 94.4% both in PO and SQ regimen, with the occurrence of adverse events 72.2% in both of two regimen. Although the SQ regimen tends to induce faster treatment response regardless of the cross-over completion, it bears no statistical significance. CONCLUSION: We conclude that the PO and SQ regimens of SMN show very comparable clinical utility in achieving therapeutic responses as well as in producing adverse events. The treatment efficacy was excellent but higher occurrence of side effects in this study, although mostly in mild degree, suggests that optimal dose adjustment strategy needs to be elaborated in Korea.

A Case of Tuberculous Epidural Abscess Developed During the Treatment of Disseminated Intracranial Tuberculosis

A 29-year-old man has been presented with disseminated pulmonary tuberculosis and brain parenchymal tuberculous nodule. The CSF examination showed the features of subacute meningitis consistent with tuberculosis, and chronic granulomatous inflammation with acid-fast bacilli was found on pleural biopsy. He was treated with anti-tuberculous chemotherapy and showed subjective improvement of the symptoms. But rather rapidly progressive weakness of lower extremities and voiding difficulty were newly developed, and the thoracic spinal MRI showed diffuse epidural abscess along the entire thoracic segment. He showed excellent clinical improvement with additive steroid therapy.

Congenital insensitivity to pain and anhidrosis with selective loss of unmyelinated fiber (Hereditory sensory autonomic neuropathy IV)

Hereditory Sensory Autonomic Neuropathy(HSAN) is variable rare disorder. So the classification of HSAN could be somewhat unsettled. There are intermingled overlap variants of HSAN in view of clinical manifestations and pathologic findings. Five types of HSAN have been described by Dyck(1993). Type I is dominantly inherited and affects both myelinated(MFs) and unmyetinated fibers(Ufs). Type II is recessively inherited and nerve biopsies show total absence of MFs but presence of Ufs. Type III is a recessive inherited dysautonomia. Type IV is characterized by insensitive to pain anhidrosis, and mild mental retardation with virtually absence of Ufs. Type V affects small MFs. We report a 5 year-old girl who presented with congenital insensitivity to pain, anhidrosis with mild mental retardation. In sural nerve biopsy, Ufs were virtually absent by electron microscopy. We reconfirmed previous pathologic findings in sural nerve of HSAN IV.

Serial follow-ups of nerve conduction studies in diabetic patients

We analyzed 177 diabetic patients(80 males, 97 females) with the nerve con duction study (NCS) performed twice or more at the interval of more than one year in Severance Hospital from Jan 1, 1984 through Dec 31, 1994. We conclude as follows: 1)The NCS follow-ups showed that diabetic polyneuropathy was getting worsened electrophysiologically as time goes by. 2)The NCS revealed that the earlier change was noticed on the distal portion of sensory nerve fiber, though diabetes was known to cause a damage to both sensory and motor nerve fibes. 3)Considering that the NCS follow-ups revealed earlier and more marked changes in amplitude than in nerve conduction velocity, axonal degeneration seems to be more responsible for the pathogenesis of diabetic polyneuropathy rather than segmental demyelination.

The Usefulness of MR Angiography in Acute Ischemic Stroke (Pilot Study for Multiple Analyses of Cause and Prognosis of Ischemic Stroke)

BACKGROUND AND OBJECTIVES: To evaluate the brain MR angiography(MRA) as a tool of diagnosis and follow up study in acute ischemic stroke. METHODS: We reviewed 90 patients of acute ischemic stroke who received thrombolytic therapy and underwent brain MRI with MRA from September 1994 to July 1995. They were divided into two groups according to carotid system and vertebrobasilar system and then positive MRA findings were defined as stenosis or occlusion of vessels in relation with MRI lesions. RESULTS: The positive MRA was shown more than 80% in large arteries and lower than 23% in small arteries. And also the MRA was shown the degree stenosis and underlying vessel abnormalities but could not precisely analyze the degree of improvement of vascular patency in this study. CONCLUSIONS: The MRA as a routine method addition to the MRI provides relatively reliable and noninvasive screening test and provides information that can be more complete evaluation and prognosis in patients of acute ischemic stroke.

A Case of Bezafibrate-induced Myopathy

One case of bezafibrate-induced myopathy was experienced and presente with a brief review of literatures. A 80-year-old woman with diabetes mellitus developed generalized myalgia and chest tightness 2 days before admission. The patient was treated with bezafibrate (800mg/day) for the previous 3 months. Serum creatine kinase, LDH and AST were markedly increased. Muscle biopsy revealed type 2 fiber atrophy. Withdrawal of the drug under the impression of bezafibrate-induced myopathy was followed by rapid clinical improvement.

A Family of Distal Myopathy with Rimmed Vacuoles

Distal myopathy with rimmed vacuoles is a rare muscle disease and, so far as we know, it has not been reported in Korea as yet. This disorder is known to be inherited as autosomal recessive trait and to have no specific treatment. Hereby, we report 3 patients of distal myopathy with rimmed vacuoles in a family. The clinical characteristics of these patients were slowly progressive symmetrical muscle weakness and wasting of all 4 extremities, worse in distal legs. The pretibial muscles were involved more markedly than the calf muscles. Serum muscle enzymes were increased. The prominent EMG findings were myopathic changes, but reduced recruitment was occasionally found in some distal muscles The muscle biopsies of right biceps brachii muscle were performed in two patients, which showed the characteristic rimmed vacuoles by light microscope. Membranous whorls and randomly oriented intracytoplasmic filaments were found by electron microscope. The severity of pathological abnormalities were related to the clinical status of the patient. One had been treated with steroid(prednisolone) for several years but with no improvement.

Relationship of the Changes in Biogenic Amines to Nitric Oxide and Oxygen Free Radicals During Cerebral Ischemia/Reperfusion

Recently oxygen free radicals and nitric oxide (NO) are known to play an important role in neuronal reperfusion injury. This study was aimed to investigate the role of oxygen f ree radicals and NO during cerebral ischemia/reperfusion, using dimethylthiourea (DMTU) and NG-monomethyl-L-arginine (NMMA), an oxygen f ree radical scavenger and a competitive NOS inhibitor respectively. In the in vivo experiment, the ischemia/reperfusion-induced changes of cerebral biogenic amines were examined in Mongolian gerbil (Meriones unguiculatus) pre-treated with NMMA and/or DMTU. To induce cerebral ischemia/reperfusion, bilateral common carotid arteries were clamped for 10 minutes and then released for 15 minutes. The biogenic amines were measured by using HPLC-ECD(High Performance Liquid Chromatography-Electrochemical detection). To confirm the results from the in vivo experiments, the effect of NMMA and/or DMTU on [3H]dopamine release from striatal slices exposed to hypoxia was investigated. The results are as follows; 1) Ischemia/reperfusion increased the ratio of DOPAC/dopamine and HVA/dopamine as well as the concentrations of DOPAC and HVA, which were evident only in corpus striatum. 2) NMMA attenuated the ischemia/reperfusion-induced increase in the ratio of DOPAC/dopamine in corpus striatum. However, the change of DOPAC or HVA was minimal. 3) DMTU attenuated the ischemia/reperfusion-induced increase of DOPAC and HVA, and the ratio ofDOPAC / dopa- mine and HVA/dopamine in corpus striatum. 4) Simultaneous pre-treatment with NMMA and DMTU attenuated the ischemia/reperfusion-induced increase of DOPAC and HVA, and the ratio Of DOPAC/dopamine and HVA/dopamine in corpus striatum. The extent of attenuation was greater than the single treatment group with NMMA or DMTU. 5) Exposure to hypoxia markedly increased the release of [3H]dopamine in the striatal slices. 6) The administration of either NMMA or DMTU attenuated the increase of [3H]dopamine release induced by hypoxia in the striatal slices. 7) The administration of both NMMA or DMTU markedly attenuated the increase of [3H]dopamine release induced by hypoxia to the extent of the control in the striatal slices. These results suggest that oxygen free radicals play an important role in cerebral ischemia/reperfusion injury, for which NO seems to be responsible.

Clinical Syndrome of Corticobasal Degeneration

Clinical features of corticobasal degeneration (CBD) can be characterized by an asymmetric akinetic-rigid syndrome with variable combinations of other deficits (corticospinal tract signs, supranuclear gaze palsy, cerebellar ataxia, cortical sensory loss, alien limb behavior, dystonia and myoclonus). Such unique combination of clinical features of CBD have lead to the general agreement that clinical diagnosis of CBD is reliable. We describe 6 patients presenting with clinical features compatible with CBD. Three had characteristic clinical features of CBD; one showed clinical features compatible with progressive supranuclear palsy, but also had apraxia and cortical sensory disturbances; one had an early CBD. The remaining one had clinical features compatible with CBD, but brain magnetic resonance imaging study showed multiple small lesions involving periventricular white matter and basal ganglia bilaterally.