Background Electromyography and nerve conduction studies (EMG-NCS) often yield nonspecific findings during the early stage of Guillain-Barré syndrome (GBS). Although useful for diagnosis, EMG-NCS are traditionally of little value in predicting a complicated clinical course, which is critical for timely decisions to initiate immunomodulatory treatment. We aimed to identify the early clinical and electrophysiologic predictors of respiratory failure, a prolonged hospital stay, and moderate-to-severe disability at discharge in GBS.
Methods We retrospectively analyzed the clinical and electrophysiologic data of adult GBS patients who were hospitalized during the early course of the disease (<2 weeks from symptom onset).
Results Eighty-one patients aged 47.5 ± 16.1 years were analyzed. The most common clinical variants were Miller-Fisher syndrome (30.9%) and classic sensorimotor GBS (25.9%). The clinical variant was not predictive of a complicated clinical course. Instead, specific clinical features such as dysautonomia (p = 0.006) and marked motor deficits (p = 0.002) were predictive of the primary composite outcome of respiratory failure and/or a prolonged hospital stay, with dysautonomia (p = 0.035) also predictive of moderate-to-severe disability at discharge. The most common abnormalities in EMG-NCS were bilateral absence of the H-reflex (86.4%) and F-wave abnormalities (44.4%). The presence of F-wave abnormalities was predictive of both respiratory failure (p = 0.032) and a prolonged hospital stay (p = 0.001).
Conclusions Early F-wave abnormalities in GBS may serve as an electrophysiologic predictor of a complicated clinical course, suggesting that EMG-NCS can provide prognostic information to guide treatment decisions during the early stage of the disease.
We report the case of somatosensory evoked potential loss during a transforaminal interbody fusion during exposure following a transient rise in blood pressure. The topography of signal loss and elimination of technical causes led to the inference of left sided stroke which was confirmed as a left thalamocapsular hemorrhagic infarct on postoperative magnetic resonance imaging. Use of intraoperative neuromonitoring in this lumbar fixation surgery helped to identify it intraoperatively and prevented undue alternative surgical decision making.
Background The younger generation in Korea easily exposed to nitrous oxide (N2O) under the name “Happy Balloon” may abuse it. N2O can irreversibly oxidize vitamin B12 and cause abnormal hematopoiesis or nervous system toxicity such as subacute combined degeneration (SCD). The objective of this study was to assist in early diagnosis of N2O-induced SCD of spinal cord by characterizing its clinical manifestations.
Methods Four patients with myelopathy after abusing N2O were enrolled. To characterize N2O-induced myelopathy, previously reported cases of N2O-induced SCD were searched through PubMed and KoreaMed. Collected cases and our four patients were analyzed.
Results A total of 30 patients with N2O-induced myelopathy (26 males and 4 females with mean age of 24 years) were analyzed. These patients took a median dose of 650 canisters for a median duration of 3.5 months. All patients presented sensory disturbances, which involved the lower extremities more frequently (100%) than the upper extremities (63.3%). Gait ataxia (76.7%), weakness in the upper (23.3%) and lower (36.7%) extremities, bladder symptoms (26.7%), Rhomberg sign (43.3%), and Lhermitte’s phenomenon (10.0%) were observed. Serum vitamin B12 levels were decreased in many (63.3%) patients and homocysteine levels were elevated in all. Of 20 patients who underwent magnetic resonance imaging (MRI) of the spine, 19 had abnormal findings. Three patients presented with contrast enhancement in lesions.
Conclusions We strongly recommend that history of N2O abuse should be asked for young patients with suspected myelopathy, especially those presenting with gait ataxia and sensory disturbances suggesting posterior column dysfunction and those presenting long-segment lesion involving the upper cervical cord on MRI.
Respiratory muscle weakness caused by neuromuscular disease can lead to both acute and chronic respiratory failure. Respiratory failure caused by Guillain-Barré syndrome and myasthenia gravis can potentially improve with disease-specific therapy. However, respiratory failure in amyotrophic lateral sclerosis is irreversible, and it may be necessary to provide full-time ventilation support along with additional assistance. Noninvasive ventilation is recommended for managing acute or acute-on-chronic hypercapnic respiratory failure caused by neuromuscular disease. It has also been effective in weaning patients off invasive mechanical ventilation. Although noninvasive ventilation offers numerous benefits over invasive mechanical ventilation, it is crucial to consider the specific contraindications and limitations of noninvasive ventilation and ensure its appropriate usage based on the patient's condition and needs. The timely recognition of neuromuscular respiratory failure is critical, as early intervention can be life-saving. This review focused on the clinical assessment and management of acute respiratory failure in neuromuscular diseases.
Breathing is controlled by complex interactions between the central and peripheral nervous systems in conjunction with the respiratory system. Neurological diseases predispose patients to nocturnal desaturation and pneumonia due to respiratory dysfunction, which increases mortality, daytime sleepiness and fatigue, and reduces the quality of life. Respiratory function tests are required to identify respiratory function decline and to consider compensatory management. This review summarizes the characteristics of several respiratory function tests and their applications to neurological diseases.
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The newly identified frontal aslant tract (FAT) that connects the posterior Broca’s area to the supplementary motor area is known to be involved in speech and language functions. We successfully intraoperatively monitored FAT using cortico-cortical evoked potentials generated by single-pulse electrical cortical stimulation in a patient with oligodendroglioma.
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Developmental trajectory of transmission speed in the human brain Dorien van Blooijs, Max A. van den Boom, Jaap F. van der Aar, Geertjan M. Huiskamp, Giulio Castegnaro, Matteo Demuru, Willemiek J. E. M. Zweiphenning, Pieter van Eijsden, Kai J. Miller, Frans S. S. Leijten, Dora Hermes Nature Neuroscience.2023; 26(4): 537. CrossRef
Subacute combined degeneration (SCD) of the spinal cord, which is a result of vitamin B12 deficiency, may cause irreversible neurological deficits. The lesion in the spinal cord is typically localized to the posterior and lateral columns, as the name implies. In this paper, we report on two patients with SCD, whose lesions involved the bilateral anterior column as well as the posterior and lateral columns. This report illustrates the importance of awareness of clinical and radiologic variable characteristics of SCD.
Primary hyperparathyroidism (PHP) is a disease in which excessive amounts of parathyroid hormone (PTH) are secreted and calcium levels in the blood increase. Hypercalcemia caused by PHP has a major influence on the peripheral nervous system and produces symptoms such as muscle cramps, paresthesia, and proximal muscle weakness. Here we report a rare case of sensory-dominant polyneuropathy caused by PHP, which improved after surgery.
Background Nitrous oxide (N2O) is used in surgery and dentistry for its anesthetic and analgesic effects. However, neurological and psychiatric manifestations of N2O abuse have been increasingly reported among Korean adults. The aim of this study was to demonstrate laboratory findings of N2O abuse in Korean patients.
Methods Patients diagnosed with N2O-induced neuropathy or myelopathy from August 2018 to December 2019 were enrolled. Their clinical presentations and laboratory and imaging findings were analyzed.
Results Sensory changes and limb weakness were present in nine of the enrolled patients. The laboratory findings revealed that seven patients had high homocysteine levels and five had high methylmalonic acid levels in their blood. Nerve conductions studies indicated that axonal neuropathy was present in four cases and longer F-wave and Hoffman’s-reflex latencies were present in two cases. Signal changes in cervical spine imaging occurred in five patients, while two had normal results.
Conclusions Chronic N2O abuse can cause neurological damage or psychiatric problems. Because N2O is illegal for recreational use in Korea, patients tend to hide their history of use. Even though the spinal imaging results were normal, clinicians should consider the possibility of N2O use, and further electrophysiological tests should be applied for precise evaluations.
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The prevalence, risks, and detection of driving under the influence of nitrous oxide Frederick R. J. Vinckenbosch, Dinesh Durán Jiménez, Hendrik Helmerhorst, Albert Dahan, Leon Aarts, Floris Bikker, Eef Theunissen, Johannes G. Ramaekers WIREs Forensic Science.2024;[Epub] CrossRef
Nitrous‐oxide‐induced polyneuropathy and subacute combined degeneration of the spine: clinical and diagnostic characteristics in 70 patients, with focus on electrodiagnostic studies L. T. Hassing, F. Y. Jiang, R. Zutt, S. Arends European Journal of Neurology.2024;[Epub] CrossRef
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Korean Society of Intraoperative Neurophysiological Monitoring , Korean Neurological Association , Korean Academy of Rehabilitation Medicine , Korean Society of Clinical Neurophysiology , Korean Association of EMG Electrodiagnostic Medicine
Ann Clin Neurophysiol 2021;23(1):35-45. Published online April 29, 2021
The utility and accuracy of intraoperative neurophysiological monitoring (IONM) has evolved greatly following the recent development of new devices for neurophysiological testing and advances in anesthesiology. Until recently, the need for IONM services has been limited to large academic hospitals, but the demand for neurophysiologists with expertise in IONM has grown rapidly across diverse types of hospital. The primary goal of the Korean Society of Intraoperative Neurophysiological Monitoring (KSION) is to promote the development of IONM research groups and to contribute to the improvement of fellowship among members and human health through academic projects. These guidelines are based on extensive literature reviews, recruitment of expert opinions, and consensus among KSION board members. This version of the guidelines was fully approved by the KSION, Korean Association of EMG Electrodiagnostic Medicine, the Korean Society of Clinical Neurophysiology, the Korean Academy of Rehabilitation Medicine, and the Korean Neurological Association.
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Background The median-to-ulnar comparison test (MUCT), and increasingly, ultrasonography (US) are considered as complementary to and more sensitive than median nerve conduction study (NCS) in diagnosing carpal tunnel syndrome (CTS).
Methods In consecutive patients with hand paresthesia compatible with CTS but with normal median NCS, we additionally performed the MUCT and analyzed whether it yielded better diagnostic sensitivity.
Results In total, 163 hands of clinically diagnosed CTS patients were examined with routine NCS. The MUCT and US were performed in 81 hands and 31 hands, respectively. While median NCS was diagnostic in 85 (52.1%) hands, MUCT failed to demonstrate superior sensitivity over median NCS in the other hands and US revealed related abnormalities better than both routine NCS (p=0.006) and MUCT (p=0.002).
Conclusions The MUCT offered no additional diagnostic benefit. On the other hand, sonographic examination had higher sensitivity for the diagnosis of CTS when applying several diagnostic criteria. Thus, US could be the screening test for diagnosing CTS prior to NCS with higher sensitivity than MUCT. However, further studies are needed to define the appropriate diagnostic criteria for US.
We performed intraoperative neurophysiological monitoring (INM) during anteromesial temporal resection (AMTR) in a patient with lesional temporal lobe epilepsy. INM revealed a sudden decrease in N20 waves in somatosensory evoked potentials (SSEPs) and poor P100 waves in visual evoked potentials (VEPs). These changes developed after applying electrocoagulation in the right mesial temporal areas. Postoperative brain magnetic resonance imaging demonstrated right thalamic and medial occipital infarctions. SSEPs and VEPs monitoring can be useful for detecting posterior cerebral artery infarction in AMTR.
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Background: The effects of omega-3 polyunsaturated fatty acids (PUFAs) on cerebral vessels have not been clarified until now. Thus we investigated the efficacy of omega-3 PUFAs supplementation on cerebral blood flow velocity and vascular resistance via transcranial doppler (TCD). Methods: Consecutive twenty patients (13 male and 7 female) with at least 1 cerebrovascular risk factor or a known cerebrovascular disease were enrolled. Patients were treated with omega-3 PUFAs (1 g, two times per day) for 12 weeks. Cerebral blood flow velocity, resistance index, and pulsatile index were checked before and after 12 weeks of treatment using TCD. Results: The change of resistance index in right MCA (from 0.58 ± 0.07 to 0.55 ± 0.07, p = 0.042) and left PCA (from 0.56 ± 0.07 to 0.53 ± 0.06, p = 0.037) showed significant improvement after 12 weeks of omega-3 PUFAs treatment. The changes in other vessels, however, failed to show any significant changes compared to the baseline. Conclusions: Omega-3 PUFAs treatment showed feasible efficacies for cerebral vascular resistances in this open label trial. To confirm these results, larger samples of patients and longer period of follow-up is warranted.
Background Neuromodulation therapy has been used to an adjunctive treatment promoting motor recovery in stroke patients. The objective of the study was to determine the effect of repetitive transcranial magnetic stimulation (rTMS) on neurobehavioral recovery and evoked potentials in rats with middle cerebral artery occlusion. Methods: Seventy Sprague-Daley rats were induced permanent middle cerebral artery occlusion (MCAO) stroke model and successful stroke rats (n=56) assigned to the rTMS (n=28) and sham (n=28) group. The 10 Hz, high frequency rTMS gave on ipsilesional forepaw motor cortex during 2 weeks in rTMS group. The somatosensory evoked potential (SSEP) and motor evoked potential (MEP) were used to evaluate the electrophysiological changes. Behavioral function of the stroke rat was evaluated by the Rota rod and Garcia test. Results: Forty rats (NrTMS=20; Nsham=20) completed all experimental course. The rTMS group showed better performance than sham group in Rota rod test and Garcia test at day 11 (p<0.05) but not day 18 (p>0.05). The amplitude of MEP and SSEP in rTMS group was larger than sham group at day 18 (p<0.05). Conclusions: These data confirm that the high frequency rTMS on ipsilesional cerebral motor cortex can help the early recovery of motor performance in permanent middle cerebral artery stroke model and it may simultaneously associate with changes in neurophysiological activity in brain.
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Iron is an important element for brain oxygen transport, myelination, DNA synthesis and neurotransmission. However, excessive iron can generate reactive oxygen species and contribute neurotoxicity. Although brain iron deposition is the natural process with normal aging, excessive iron accumulation is also observed in various neurological disorders such as neurodegeneration with brain iron accumulation, Parkinson’s disease, Alzheimer’s disease, multiple sclerosis, Friedreich ataxia, and others. Magnetic resonance image (MRI) is a useful method for detecting iron deposits in the brain. It can be a powerful tool for diagnosis and monitoring, while furthering our understanding of the role of iron in the pathophysiology of a disease. In this review, we will introduce the mechanism of iron toxicity and the basics of several iron-related MRI techniques. Also, we will summarize the previous results concerning the clinical application of such MR imagings in various neurological disorders.
Background Vstibular evoked myogenic potentials VEMP) have been known to be useful documenting abnormality in patients with various vestibular disorders and brainstem lesions but the studies of VEMP in patients with hemispheric lesions are rare.
Methods We recorded VEMP in 21 consecutive patients with acute ischemic stroke in the supratentorial lesions without evidence of brainstem or vestibular end organ lesions. All patients underwent magnetic resonance imaging and the main outcome measures of VEMP were recorded in all subjects. We interpreted each parameters of VEMP using our normal laboratory data.
Results VEMP abnormalities(prolonged latency or asymmetry of amplitude) were found in 57%(12/21) of acute infarction patients with supratentorial lesions. Bilateral VEMP abnormalities were found in six patients and unilateral abnormalities were found in another six patients with ipsilateral abnormalitiesin the three and controlateral abnormalities in the three patients.
Conclusions VEMP abnormalities were found in supratentorial stroke patients in our studies and this findings suggest supranuclear control may affect the generation of VEMP potentials.
Among the various physiological factors that affect nerve conduction velocity (NCV), temperature is the most important. Because the influence of temperature is the most important source of error. It is known from animal experiments that conduction is eventually completely blocked at low temperatures, the myelinated A fibers being the first affected and the thin fibers of group C the last. Many studies showed that the NCV decreases linearly with lowering temperature within the physiological range. The distal motor latency increased by 0.2 msec/
Trancranial Doppler(TCD) monitoring is a new application of ultrasonography which allows the nonivasive detection of blood flow velocity in the horizontal (MI) segment of the middle cerebral artery (MCA) and detects microembolic phenomena in the cerebral circulation. Recent studies emphasized the potential of using this technique in vascular surgery (carotid endarterectomy, cardiopulmonary bypass), interventional and intensive care setting. Although the disparity between CBF and blood flow velocity and number of microemboli could be used to prevent cerebral ischemic and embolism based on clinical studies. A reduction of more than 60% of MCA can reflex hemodynamic ischemic state and acoustic feedback of high intensity transient signals(HITS) from the TCD monitoring unit has a direct influence on surgical technique. TCD monitoring can immediately provide information about thromboembolism and hemodynamic changes, which may be a useful tool in the study and prevention of stroke.
Background : The generators of N37 and P37 of posterior tibial nerve somatosensory evoked potential(PTSEP) have not been exactly known. Recently, some reports suggested that P37 and N37 might have different generator. We conducted a study to know the generators of P37 and N37 of PTSEP using gating mechanism. Methods : We evaluated subcortical and cortical somatosensory evoked potentials(SEPs) in response to posterior tibial nerve stimulation in 2 experimental conditions of foot movement and compared them with PTSEPs in full relaxation of foot. The experimental conditions were: (a) active flextion-extention of stimulated foot, (b) isometric contraction of the stimulated foot, (c) passive flextion-extention of the stimulate foot. We analyzed the latencies and amplitudes of following potentials;P30, N37, P37, and N50. Results : The amplitude of P30 potential did not change during at any paradigms. Te amplitudes of P37 and N50 were significantly attenuated in all condition. However, the amplitude of N37 showed no significant change during at any paradigms. Conclusions : These results suggest that the generators of P37 and N37 pf PTSEP be different I cortex.
Background ad Aims : Nerve conduction study is invaluable in clinical neurology, especially for assessing peripheral neuropathies. Abnormal nerve conduction studies may result not only from peripheral nerve dysfunction itself, but also from other various mechanical, technical, and physiological factors such as age, sex, height and temperature. So we conducted this study to establish the our own normal values. Methods : In this study, from March. 1997 to July. 1998, 40 Korean adults among person came to Health Promotion extremity and distal segments. Physiological factors such as age, height and temperature affect the results of nerve conduction studies in multiple regression analysis. The sex difference is recognized over peroneal motor nerve. There are no sex difference in amplitude transformed into normal distribution. The significant physiological factor affecting
Intraoperative neuromonitoring (INM) is well known to be useful method to reduce intraoperative complications during the surgery of nervous system lesions. Evoked potentials are most commonly used among the electrophysiological tests. Brainstem auditory evoked potentials are for detecting the problems along the auditory pathways including the eighth cranial nerve and brainstem. Somatosensory evoked potentials are applied for preventing the spinal cord lesions. The INM is affected by many factors. In order to perform an optimal INM, the confounding factors including technical, anesthetical, and individual factors should be kept well under control. INM has frequent electrophysiologic changes during the surgery and it might be helpful to keep one
B a c k g r o u n d : Spatial analysis of EEG is a phenomenal assessment and not so informative for phase space anddynamic aspect of EEG data. In contrast, nonlinear EEG analysis attempts to characterize the dynamics of neural networksin the brain. We have analyzed the features of EEG nonlinearly in subjects with white matter change on brainMRI and compared the results with cognitive function in each.Methods : Digital EEG data were taken for 30 seconds in 9 subjects with white matter degeneration and in 5 healthynormal controls without white matter change on MRI. Then we analyzed them nonlinearly to calculate the correlationdimension(D2) using the MATLAB software. The cognitive function was assessed by 3MS(modified mini-mental stateexamination). The severity of white matter change was assessed by Scheltens scale.Results : The mean D2 value of normal control was greater than that of white matter degeneration group. The D2s ofsome channels were correlative with 3MS and degree of white matter degeneration significantly.Conclusions : nonlinear analysis of EEG can be used as one of adjuvant functional studies for prediction of cognitiveimpairment in subjects with white matter degeneration and subcortical white matter change can be influential on cognitivefunction and correlation dimension of EEG.
The function of the visual system is to locate objects in space, decide if they are moving, and determine if they are familiar. Light is focused onto an array of retinal receptors and converted to neural signals that are sent to primary visual cortex, where elementary features such as color, form, depth, and motion are separately encoded. Motion and depth information is conveyed to the occipitoparietal cortex, where spatial percepts are derived. Color and form information is conveyed to the occipitotemporal cortex, where it is interpreted as familiar or unfamiliar. Many other neocortical regions contribute attentional and motivational inputs that help to select and bind relevant features into meaningful visual symbols. We discuss about optical, retinocortical, and integrative component of visual system.
Background Although quantitative sensory test (QST) is being used with increasing frequency for measuring sensorythresholds in clinical practice and epidemiologic studies, there has been no age-matched normative data in Korean adults.The objective of this study is to evaluate the value of QST in diabetic polyneuropathy with normal range in Korean adults.Methods: The Computer Aided Sensory Examination IV 4,2 (WR Medical Electronics Co., Stillwater, Minnesota, U.S.A.),with 4,2,1 stepping algorithm was used to determine vibration and cold perception threshold in 70 normal controls and 19patients with diabetic polyneuropathy aged from 21 to 79 years. The data were used to define age-matched upper and lowernormal limits and normal range of side to side difference. We also evaluated the duration of diabetes, serum HbA1C level,and findings of nerve conduction study (NCS) and QST in patients with diabetic polyneuropathy. Results: In normal adults,sensory thresholds slightly increased with age, and a slight side-to-side difference was observed. The diagnostic sensitivityof QST was not higher than NCS in patients with diabetic polyneuropathy (36.8% vs. 42.1%, p=0.716), especially amongelderly patients. Conclusions: QST might be used as a complementary test for NCS in the diagnosis of diabeticpolyneuropathy. Although the QST is a simple method for the evaluation of peripheral nerve function, there are somelimitations. Most of all, because the QST measuring is dependent on the subjective response of patients, the degree of concentrationand cooperation of the patients can significantly affect the result. And thus, attention should be paid during theinterpretation of QST results in patients with peripheral neuropathy.
Background Mobile phone has become a very popular device used in everyday our lives. However, the possible hazard to human body such as brain tumor has been proposed intermittently. This unwanted possibility was calmed down due to the absence of definite evidence of hazard. This study was performed to see the effect of mobile phone use on the brain temperature. Methods: In 20 volunteers, We performed 4 steps of temperature measuring procedure. Four steps are pre-use (SI, basal state), wire-phone (S2, conventional telephone), PCS phone (S3, using 1,750~1,900MHz), cellular phone (S4, using 820 MHz) states. Brain temperatures were measured by radiothermometer at 10 sites (5 sites in each hemisphere) of the brain after 5 minutes of telecommunication through the phones. The final data were compared using paired t-test. Results: In PCS user group (Average; 35.73708
Electroencephalography(EEG) involves the recording and analysis of electrical signals generated by brain. Resolution of true electrical brain activity requires three elements: good equipment, meticulous recording technique, and informed interpretation of data. Every electroencephalographer should be familiar with the science and engineering underlying clinical EEG. This article reviews principle of EEG instrument & methods of recording; History of EEG, EEG instrument, EEG amplifier & its control, Calibration, Electrode, Electrode placement, Montage, and Electrical safety.
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