Complete surgical resection is a well-known therapeutic gold standard for spinal ependymoma, but it is associated with high postoperative morbidity. Intraoperative neuromonitoring (INM) is important for detecting and reducing the rate of surgical complications during this operative procedure. We report a case of postoperative paraplegia due to tumor bleeding during the operation. INM of the patient revealed abrupt loss of waveforms during the operation. This finding suggested that INM is helpful for detecting intraoperative hematomyelia and minimizing postoperative neurologic sequelae.

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.

Citations

• 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

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.

Citations

• Intraoperative Monitoring of Sensory Evoked Potentials in Neurosurgery: A Personalized Approach
  Evgeny A. Levin
  Journal of Personalized Medicine.2025; 15(1): 26.     CrossRef
• Role of Intraoperative Neurophysiological Monitoring in Pediatric Tethered Cord Syndrome Surgeries and Technical Insights
  Wael Abd Elrahman Ali Elmesallamy, Alshaimaa Abdel Fattah Kamel, Ahmad Fahmy, Mohamed Elbana, Mahmoud M. Taha
  Indian Journal of Neurosurgery.2025;[Epub]     CrossRef
• A multichannel electromyography dataset for continuous intraoperative neurophysiological monitoring of cranial nerve
  Wanting Ma, Lin Chen, Xiaofan Pang, Yuanwen Zou
  Data in Brief.2024; 53: 110250.     CrossRef
• Intraoperative neuromonitoring in intracranial surgery
  G.B. Adkins, A. Mirallave Pescador, A.H. Koht, S.P. Gosavi
  BJA Education.2024; 24(5): 173.     CrossRef
• Neurophysiological monitoring during endovascular treatment of brain arteriovenous malformations: A meta-analysis
  Francesco Diana, Michele Romoli, Federico Sabuzi, Aymeric Rouchaud, Charbel Mounayer, Géraud Forestier, Alejandro Tomasello, Manuel Requena, David Hernández, Marta De Dios Lascuevas, José Luis Cuevas, Simone Peschillo, Jildaz Caroff, Thanh N. Nguyen, Moha
  Interventional Neuroradiology.2023;[Epub]     CrossRef
• Intraoperative neurophysiological monitoring during the surgeries for the ossification of the posterior longitudinal ligament
  Seol-Hee Baek
  Journal of Intraoperative Neurophysiology.2022; 4(2): 55.     CrossRef
• Hemodynamic Consideration in Intraoperative Neurophysiological Monitoring in Neuromuscular Scoliosis Surgery
  Seok Young Chung, Chae Hwan Lim, Yoon Ghil Park, Hak Sun Kim, Dawoon Kim, Jinyoung Park
  Annals of Rehabilitation Medicine.2022; 46(6): 292.     CrossRef
• Undetected abulic state after anterior communicating artery aneurysm surgery under motor evoked potential (MEP) and somatosensory evoked potential (SEP) monitoring
  Hyesun Lee, Jinseok Park
  Journal of Intraoperative Neurophysiology.2022; 4(2): 78.     CrossRef
• Intraoperative neurophysiological monitoring in pituitary adenoma surgery: case report
  Hyun-Wook Nam, Seol-Hee Baek
  Journal of Intraoperative Neurophysiology.2021; 3(2): 108.     CrossRef

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.

Citations

• Intraoperative and extraoperative neurophysiological monitoring in epilepsy surgery
  Dae Lim Koo, Dae-Won Seo
  Journal of Intraoperative Neurophysiology.2021; 3(1): 16.     CrossRef

Since Hans Berger reported the first paper on the human electroencephalogram in 1920s, huge technological advance have made it possible to use a number of electrophysiological approaches to neurological diagnosis in clinical neurology. In majority of the neurology training hospitals they have facilities of electroencephalography(EEG), electromyography(EMG), evoked potentials(EP), polysomnography(PSG), electronystagmography(ENG) and, transcranial doppler(TCD) ete. Clinicials and electrophysiologists should understand the technologic characteristics and general applications of each electrophysiological studies to get useful informations with using them in clinics. It is generally agreed that items of these tests are selected under the clinical examination, the tests are performed by the experts, and the test results are interpretated under the clinical background. Otherwise these tests are sometimes useless and lead clinicians to misunderstand the lesion site, the nature of disease, or the disease course. In this sense the clinical utility of neurophysiological tests could be summerized in the followings. First, the abnormal functioning of the nervous system and its environments can be demonstrated when the history and neurological examinations are equivocal. Second, the presence of clinically unsuspected malfunction in the nervous system can be revealed by those tests. Finally the objective changes can be monitored over time in the patient's status. Also intraoperative monitoring technique becomes one of the important procedures when the major operations in the posterior fossa or in the spinal cord are performed. In 1996, the Korean Society for Clinical Neurophysiology(KSCN) was founded with the hope that it will provide the members with the comfortable place for discussing their clinical and academic experience, exchanging new informations, and learning new techniques of the neurophysiological tests. The KSCN could collaborate with the International Federation of Clinical Neurophysiology(IFCN) to improve the level of the clinical neurophysiologic field in Korea as will as in Asian region.1 In this paper the clinical neurophysiological tests which are commonly used in clinical neurology and which will be delt with and educated by the KSCN i the future will be discussed briefly in order of EEG, EMG, EP, PSG, TCD, ENG, and Intraoperative monitoring.

In clinical neurology various different electrophysiological tests are widely used to demonstrate the unsuspected malfunctioning in the nervous system and to monitor over time the clinical status of patients. In addition clinical neurologists and neurosurgeons take advantage of the intraoperative monitorings to increase the quality of neurosurgical operations in the posterior fossa, in the spinal cord, or in visual pathways. In the field of movement disorders, electrophysiological tests provide neurologists with making accurate differential diagnoses with useful therapeutic tests it could be possible for us to evaluate the types of blephalospasm, the extent of hemifacial spasm, the level of myoclonus, and the prime muscle of torticollis etc. Sometimes the myographic guidance may be critical for choosing the exact injecting site of botulinum toxin. These several decades various electroencephalographic and evoked potential tests had been utilized in the electrophysiological laboratories to understand the basic pathophysiology of myoclonus, spasticity and other central motor dysfunctions. It could be one of the breakthroughs in the area of behavorial neurology that the brain function can be mapped by the spontaneous or evoked electrical activities of nervous system since the movement related potentials (MRPs) had been studies for several decades. Various reflex tests such as masseter reflex, blink reflex, click evoked vestibulocollic reflex, facial reflex, stretch reflex, flexor reflex, H-reflex recovery curve, vestibulbar inhibition of H-reflex, reciprocal inhibition, recurrent or Renshaw reflex, Ib inhibition, cutaneous reflex have been also used to understand normal or abnormal physiology in movement disorders. Polysomnography, posturography and gait studies are also applied in clinical neurology in association with movement disorders which are useful in deciding the treatment regimen.

Hippocampal slice models can be a powerful tool to study the mechanism of partial epilepsy. Despite the loss of connection with the rest of the brain, in vitro hippocampal slice preparations allow detailed physiological and pharmacological studies, which would be impossible, in vivo. There are several methods to induce electrographic seizures on hippocampal slice models. Those are electrical pulse train stimulation, 0 Mg2+ artificial cerebrational fluid and high concentration of extracelluar K+ on bath. Among them, the electrically triggered seizure may mimic the physiological communication between neuronal populations without any deterioration of normal physiologic and chemical status of the hippocampal slice models. Presumably, such communication from hyperexcitable areas to other neuronal populations is involved in the development of epilepsy. Eelectrographic seizures in hyppcampal slice models occur in the network of neurons that are involved in epileptic seizures in the hippocampus in vivo. Because these models have many advantages and are very valuable to research of epileptogenesis on partial epilepsy, I would like to introduce the electrophysiological methods to induce electrographic seizure or epilepsy on hippocampal slice models briefly in this paper.

Myoclonus is a brief muscle jerk caused by neuronal discharge. Myoclonus can be classified from various points of view such as (1) clinical presentaiton; (2) neurophysiological origin; and (3) etiology. Among them, classification on the basis of the underlying pathophysiology is most reasonable. However underlying pathophysiologies of myoclonus have not been well known, evolving electrophysiologic studies aid in making the diagnosis and privide insight into the pathophysiology of myoclonus. Furthermore these Can differentiate myoclonus from other movement disorders, and positive from negative myoclonus; more importantly, these reveal the origin of the discharges producing the jerks. Myoclonus could be classified into two broad groups, epiletic and nonepiletic, according to the different electrophysiologic findings. Epiletic myoclonus could also be subclassified into several groups according to the location of the presumed generators suspected by current electrophysiologic findings.

Tremor is an approximately rhythmic, roughly sinusoidal involuntary movement. Despite nearly a century of modern clinical and laboratory investigations, no tremor is understood completely. Human tremors derive from different etiologies and thus, not suprisingly, the physiologies are diverse. Tremors may derive from mechanical oscillations, mechanical reflex oscillations, normal central oscillators, and pathologic central oscillators. However the definitive identification of oscillators for any tremor have not yet been established. Measuring tremor clinically is difficult because tremors behave in different and often complex ways. There are several different techniques for measuring tremor. One of most popular and sensitive methods use accelerometries. An excellent method consists of accelerometry and EMG combined with spectral analysis and weighting of the body part, which allows separation of tremors coming from mechanical reflex and central oscillators. Now times, increased power and speed of microprocessors enable clinical laboratories to quantify tremor and other aspects of motor disability with accuracy and precision not possible a decade ago.

Artifacts in an electroencephalography are the signals not originated in the cerebrum. Generally, the artifacts are categorized into physiological artifacts and nonphysiological artifacts. An artifact created in the generator existing in the body but not originated in the brain is physiological and an artifact occurred by various causes existing outside of the body is nonphysiological. The physiological artifacts are occurred by eyeball movement, electrocardiogram, tongue movement, skin potential and body movement, and the nonphysiological artifacts by instrument, electrode, environment and digital signal defect. To recognize and eliminate the artifacts caused by various origins is responsibility of the EEG technician primarily. However even an EEG technician abundant in experiences cannot remove all artifacts. The EEG technician must give information about the artifacts which he/she was not able to remove after endeavoring to the EEG interpreter. The responsibility about the quality control of EEG is fundamentally on the EEG interpreter. The EEG interpreter must accumulate the knowledge about artifacts abundantly to advise the EEG technician to correct frequently occurred artifacts and to determine the artifacts recorded in the EEG correctly.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder that primarily affects motor neurons.The characteristic features of this devastating disorder are the simultaneous presence of upper and lower motor neuron(LMN) signs with progression from one region of the neuraxis to the next and eventual death, typically from respiratorycompromise.Electrophysiological studies are an indispensible part of the ALS evaluation, especially serving as an extension of theclinical examination, and most useful in identifying LMN dysfunction. Not only may electrodiagnostic studies revealcharacteristic changes in those regions clinically manifesting signs, but it also serves to disclose asymptomatic areas ofinvolvement.

Background
Miller-Fisher syndrome (MFS) is characterized by the clinical triad of ophthalmoplegia, ataxia, and areflexia,and is considered a variant form of Guillain-Barre syndrome. Although some cases of delayed-onset facial palsy in MFShave been reported, the characteristics of this facial palsy are poorly described in the literature. Methods: Between 2007and 2010, six patients with MFS were seen at our hospital. Delayed facial palsy, defined as a facial palsy that developedwhile the other symptoms of MFS began to improve following intravenous immunoglobulin treatment, was confirmed in fourpatients. The clinical and electrophysiological characteristics of delayed facial palsy in MFS, as observed in these patients,are described here. Results: Four patients with delayed-onset facial palsy were included. Delayed facial palsy developed 8-16days after initial symptom onset (5-9 days after treatment). Unilateral facial palsy occurred in three patients and asymmetricfacial diplegia in one patient. The House-Brackmann score of facial palsy was grade III in one patient, IV in two patients,and V in one patient. None of the patients complained of posterior auricular pain. Facial nerve conduction studies revealednormal amplitude in all four patients. The blink reflex showed abnormal prolongation in two patients and the absence ofaction potential formation in two patients. Facial palsy resolved completely in all four patients within 3 months. Conclusions:Delayed facial palsy is a frequent symptom in MFS and resolves completely without additional treatment. Thus, standardtreatment and patient reassurance are sufficient in most cases.