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.

Background
& Objectives :In cerebral palsy, spastic paraplegia is one of the most crippling motor manifestations. Reducing the spasticity may improve gait and decrease the incidence of lower-extremity deformities. The spasticity may result from abnormally increased afferent signals via dorsal roots onto interneurons and anterior horn and spreading of reflex activation to other muscle groups. To assess the influence of dorsal rhizotomy to spasticity, the authors analyzed five cerebral palsy patients with spastic paraplegia. Methods : The operation entailed and L1-2 laminectomy, ultrasonographic localization of conus medullaris and identification of lumbosacral dorsal roots. The innervation patterns of each dorsal root were examined by electromyography (EMG) responses to electrical stimulation. Tetanic stimulation was applied to individual rootlets of each root after reflex threshold was determined. the reflex responses were graded and rootlets producing high grade response were selected and cut. Short-term postoperative evaluations were performed. Results : Intraoperative EMG monitoring was satisfactorily performed in all five cases. One month after the operations, all patients showed greatly reduced spasticity which was measured by the instrumental gait analysis. Bilateral knn and ankle jerks were normalized and tip-toe gait with scissoring disappeared in all patients. Conclusion : Intraoperative EMG monitoring seems useful for the selective dorsal rhizotomy to reduce spasticity.

In the normal neuromuscular junction, the nerve action potential(NAP) opens the P-type calcium channels, and resultant influx of calciumions produces the simultaneous exocytosis of

Background
Needle electromyography (EMG) and motor evoked potential (MEP) of the genioglossus (tongue) aredifficult to perform in evaluations of the craniobulbar region in amyotrophic lateral sclerosis (ALS). Therefore, weinvestigated the yields of needle EMG and MEP recorded from the upper trapezius, since it receives innervation fromthe lower medulla and upper cervical cord.Methods: Needle EMG and MEP of the upper trapezius were obtained in 17 consecutive ALS patients. The needleEMG parameters recorded included abnormal spontaneous activity and motor unit action potential (MUAP) morphology.An upper motor neuron (UMN) lesion was presumed when either response to cortical stimulation was absent, or thecentral conduction time was delayed (>mean+2SD).Results: Of the five patients with bulbar-onset ALS, four had abnormalities in the upper trapezius and four in thetongue by needle EMG. In contrast, of the 12 patients with limb-onset ALS, 11 had abnormalities in the upper trapezius,and only five in the tongue. When MEP was performed, it was found that three of the five patients with bulbar symptomsand three of the six patients with isolated limb involvement had abnormal MEP findings.Conclusions: Electrophysiological studies of the upper trapezius are more sensitive those of the tongue in patientswithout bulbar symptoms. Thus, needle EMG and MEP of the upper trapezius are alternative tools for assessing bulbarand rostral neuraxial involvement in the diagnosis of ALS.

Introduction : Orthostatic tremor develops in the legs while standing up with no weakness, pain or imbalance in theleg and the tremor is characteristically not observed when walking. However there have been some confusions aboutorthostatic tremor in several aspects. For the past ten years, we have observed 4 patients with orthostatic tremor. In eachcase tests were performed to investigate the following three important areas of inquiry about orthostatic tremor. Firstly,whether this disorder is an independent diagnostic entity or a variant of essential tremor. Secondly, whether the progressof this disorder is specifically related with standing posture. Lastly, the nature of the pathophysiologic mechanismbehind the appearance of the tremor when standing after the lapse of a certain latent period and its disappearance uponthe commencement of walking.Methods : Our 4 cases of orthostatic tremor were studied clinically, electrophysiologically, and pharmacologically.Electrophysiological tests included tremor spectrum test and electromyography.Results : We observed the presence of this tremor in several other tonic postures, as well as its absence, in a verticallylifted position from all our cases. Our cases registered a variable tremor frequency between 5 and 12 Hz according tothe tremor spectrum test and EMG. Furthermore all our 4 cases demonstrated patterns of both synchronous EMG activityand alternating EMG activity at various times in homologous muscles of both legs. Orthostatic tremor was improvedsignificantly with propranolol as well as clonazepam.Conclusions : From the results of our study we drew the following conclusions. It is probable that orthostatic tremoris simply a variant of essential tremor rather than being an independent diagnostic entity and that in most cases itsdevelopment is specifically related with muscle contraction rather than merely with the act of standing. Furthermore wediscovered a clue in the previously described neural control mechanism that the nuclear bag fibers in the muscle spindlehave lag time of several seconds in their response to muscle strength and that their baseline does not reset fully in rapidlymoving muscle. This neural control mechanism could offer sufficient explanation for the phenomena of tremorappearance when standing and disappearance when walking in orthostatic tremor.

Blepharospasm and apraxia of lid opening(ALO) are non-paralytic causes of involuntary eyelid closure. Clinically itis difficult to differentiate blepharospasm and ALO, and these two conditions are sometimes associated. We report acase of pretarsal blepharospasm presenting as apraxia of lid opening. 55-year-old woman was noted to have voluntaryeye opening difficulty. We synchronously record the electromyographic(EMG) from the levator palpebrae superiorisand the orbicularis oculi muscles in this patient. This results suggested that she has a variant of blepharospasm due toabnormal contraction in the pretarsal orbicularis oculi.