Clinical Neuroscience

[Physical and electrophysiological aspects of electroconvulsive therapy (review)]

GAZDAG Gábor

DECEMBER 20, 2003

Clinical Neuroscience - 2003;56(11-12)

[Personnel and technical conditions for ECT (electroconvulsive therapy) is legally determined. In this article the author reviews studies focused on the technical questions of ECT. After the comparison of the unilateral and bilateral electrode placement an analysis is given on the physical properties of the stimulus used to elicit seizures. After discussing the questions of dose, vaweform frequency and polarity, the anatomical and physiological factors of impedance are evaluated. The author then discuss gender, age and encephalopathy as factors influencing seizure threshold. The connection between symmetry, regularity, and postictal suppression registered on the EEG and efficacy is observed. The EEG and EMG concordance is supposed to be connected also with the efficacy. In the discussion the author gives recommendations based on the literature.]

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Clinical Neuroscience

[Thallium poisoning induced polyneuropathy - clinical and electrophysiological data]

LUKÁCS Miklós

[Introduction - The aim of the study was the electrophysiological investigation of thallium induced polyneuropathy. Beyond the rarity of the illness, the motivation of this work was the possibility of following up the pattern of neuronal damage. Thallium is one of the most toxic heavy metal and its wide use increases the chance of chronic or accidental acute poisoning. The entero-hepatic circulation makes the accumulation of this toxic agent in tissues possible, mostly in neurons, in the epithelial cells of the digestive tract, in the germinative cells of the skin and testicles. In addition to alopecia and digestive complaints, the clinical picture of thallium poisoning is dominated by neurological signs. Severe axonal polyneuropathy develops in almost all cases, with further damage to the retina and impairment of cognitive functions being not unusual. The diagnosis is confirmed by finding high levels of thallium in body fluids, especially in saliva and urine. Case report - Electrophysiological examination of our accidentally poisoned patient revealed severe, sensory-motor, predominant motor axonal polyneuropathy and pointed out some aspects of the pattern of neurotoxic process: the initially distal lesion, the dying-back course and the capacity for regeneration. Conclusion - Because thallium has the same molecular targets as potassium ion thus impairing the energetical supply of the nerve cell, the most effective treatment is carefully loading with potassium. If recognized and treated early, thallium poisoning has a favourable prognosis.]

Clinical Neuroscience

[Predictors of lethal outcome in subdural haemorrhage]

SÁNDOR János, SZÜCS Mária, KISS István, EMBER István, CSEPREGI Gyula, FUTÓ Judit, VIMLÁTI László, PÁL József, BÜKI András, DÓCZI Tamás

[Background - Subdural haemorrhage (SDH) is of high public health importance because of its frequency, high case fatality ratio (CFR) and the young age of affected population. Despite the fact that the effectivity of guideline based treatment has been improved in the last decade, the Hungarian praxis shows variable compliance for recommendations. Objectives - The study aimed to describe the heterogeneity of the treatment effectivity (by geographically identifying the populations provided with appropriate or non-optimal level care), to determine the relationship between the institutional praxis quality and the results of treatment for SDH by linking the praxis properties to the patients' records. Methods - The institutions’ protocols were assessed by a self-completed questionnaire in 1997. The participating hospitals treated 79% of the Hungarian patients with SDH. The Hungarian hospital discharge data in 1997-1999 were the source of patient specific data. The risk factors of lethal outcome were investigated by logistic regression analysis. Results - High proportion of patients had been treated in hospitals with low compliance for guidelines. The non-permanent access to neurosurgical service and CT facility, the lack of intracranial pressure monitoring and the respiration support provided out of intensive care units worsened the survival of subjects. It was quantified that the full compliance could have diminished the case fatality ratio by 15-20%. The ratio of extreme county level CFRs exceeded 2.36 and extrapolating the effectivity observed in the county with lowest lethality, the Hungarian CFR would have been reduced by 21% among patients with SDH main diagnosis. (The interpretation of findings is limited by the lack of differentiation between acute and chronic cases and of direct categorisation of severity for subdural haemorrhage in the official hospital discharge records.) Discussion - The study results urge the increase of compliance for evidence based guidelines, since despite of some validity issues, it was demonstrated that the deviation from recommended practice is reflected in the disadvantageous outcome.]

Clinical Neuroscience

[Assessment of motor impairment with electromyography - the kinesiological EMG]

HORVÁTH Mónika, FAZEKAS Gábor

[Kinesiological electromyography means the application of the surface EMG measurement technique during movement and locomotion. The authors investigated the motor impairments of the upper limb of patients with spastic hemiparesis. Surface EMG activity in musculus biceps brachii and musculus triceps brachii were recorded during voluntary elbow flexion and extension movements. In some cases even the raw EMG signals contain the accurate information but more often the recorded signals should further be processed to achieve more valuable data concerning muscle performance. The limitations of the technique underlines the importance of the several steps of the processing. The purpose of this study is to present a systematic description of the methods and the precise application of surface EMG. The authors give a comprehensive view of different processing methods and demonstrate the application areas of the kinesiological EMG.]

Clinical Neuroscience

[HIV infection and neurology - long term follow-up of HIV infected children]

KOLLÁR Katalin, JELENIK Zsuzsanna, HEGELSBERGER Edit

[Objectives - Before the widespread introduction of combined antiretroviral therapy (1995) complications from HIV and AIDS in the central nervous system had been reported in larger proportion in infants and children than in adults: 80-90% versus 60-70%. Particular clinical manifestations tend to occur at different stages during the evolution of HIV infection. The authors review the neurological aspects of HIV infection. Method - First, a summary of the protocol of the neurological examinations and related experience is given. Then authors present the evaluation of neuro-psychological development, prevalence of neurological impairment and neuro-imaging of nine HIV infected children (seven boys, two girls) for the period of ten years (1991-2001). Three/ten children had vertically transmitted HIV, six/nine were infected by a nosocomial route in their early childhood. Children were regularly followed up from the diagnosis of HIV. The median follow up time has been 79 month (range: 18-144 month). Four patients died during the study period. The neurological status, the motor and mental development were examined at three month intervals or monthly under one year of age. EEG was performed every six month and CT/MRI once a year. All patients received combined antiretroviral treatment and immunglobulin therapy continuously. Results - Three/nine children have normal development, one/nine has hyperactive and attention deficit disorder with normal IQ range, two/nine have slight, one/nine moderate and two/nine serious mental retardation. Mild neurological signs were found in two children, various moderate and serious neuro/psychological symptoms were found in four patients, one of them was treated with benign epilepsy too. There was also close correlation between the clinical symptoms and the results of EEG examination (diffuse background slowing) and results of neuroimaging studies (cortical atrophy, calcification of the basal ganglia, toxoplasma abscesses). According to the results of different examinations three/nine children were found to be symptom-free, one/nine case showed the static form, two/nine patients showed the plateau form, two/nine the rapid progressive form and one/nine the progressive infantile form of AIDS encephalopathy. The majority of the patients suffered from adapting problems and difficulties of socialisation since their families lives were damaged by isolation and rejection from the community. Conclusion - The regular neurological and psychological examinations completed with EEG, CT/MRI were very informative to follow the course of neuro-psychological problems of HIV infected children. Symptom-free patients have to face psychosocial problems too, which cause much more damage in their mental progress than HIV itself.]

Clinical Neuroscience

[Occipital sinus in patients suspect for dural sinus thrombosis - Case report]

OSZTIE Éva, MARTOS János

[Introductions - The diagnosis of dural sinus thrombosis despite of using modern imaging techniques still remains a difficult problem. For satisfactory interpretation of CT and MR scans it is indispensably important the knowledge of anatomical variations and possible imaging artifacts. One of the relatively rare developmental variations - giving chance for making false positive diagnosis - is the occipital sinus with hypoplasia or agenesis of transverse sinus. Case reports, Conclusion - The incidence, the anatomical classification, the importance and the possibility of differentiation from sinus thrombosis are reviewed based on case reports of four patients.]

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Clinical Neuroscience

The yield of electroencephalography in syncope

NALBANTOGLU Mecbure, TAN Ozturk Ozlem

Introduction - Syncope is defined as a brief transient loss of consciousness due to cerebral hypoperfusion. Although the diagnosis of syncope is based on a thorough history and examination, electroencaphalography (EEG) is also an important investigational tool in the differential diagnosis in this group of patients. In this study we aimed to identify the diagnostic value of EEG in patients with syncope. Methods - We retrospectively examined EEG recordings of 288 patients with the diagnosis of syncope referred to the Cankiri State Hospital EEG laboratory, from January 2014 to January 2016. The EEG findings were classified into 6 groups as normal, epileptiform discharges (spike and sharp waves), generalized background slowing, focal slowing, hemispherical asymmetries, and low amplitude EEG tracing. The EEGs were separated according to gender and age. Results - Total of 288 patients were included in this study, 148 were females (51.4%) and 140 (48.6%) were males. Among all the EEG reports, 203 (70.5%) were normal, 8 of them (2.8%) showed generalized background slowing and 7 (2.4%) demonstrated focal slow waves. Epileptiform discharges occured among 13 patients (4.5%). Hemispherical asymmetries were detected in 10 patients (3.5%) and low amplitude EEG tracing in 47 patients (16.3%). There was no significant difference between age groups in EEG findings (p=0.3). Also no significant difference was detected in EEG results by gender (p=0.2). Discussion - Although the diagnosis of syncope, epilepsy and non-epileptic seizures is clinical diagnosis, EEG still remains additional method

Clinical Neuroscience

[Selective dorsal rhizotomy in the treatment of spasticity - Hungarian experiences ]

FEKETE Gábor, NOVÁK László, VEKERDY-NAGY Zsuzsanna, BOGNÁR László

[Objective - We summarize our initial experiences with selective dorsal rhizotomy that we introduced in Hungary to manage the spasticity of patients with cerebral palsy. Patients and methods - Thirty spastic patients were enrolled in our study. All of the patients were operated between July 2014 and June 2015. We performed selective dorsal rhizotomy from a single-level approach at the level of conus medullaris in all cases, with electrophysiological control. Results - We could perform the surgery in all cases safely. Adverse events related either to damage of neurological structures, or to surgery did not occur. The planned rehabilitation courses before and after the operations are in progress in all cases. Conclusion - Selective dorsal rhizotomy is an irreversible surgical intervention to treat spasticity. With sufficient experience and electrophysiological control it can be performed safely, and the early results are promising. ]

Clinical Neuroscience

[ELECTROPHYSIOLOGICAL SIGNS OF STRUCTURAL CHANGES IN MOTOR UNITS AFTER ISCHAEMIC STROKE]

LUKÁCS Miklós

[Introduction - While it is several decades ago that electrophysiological studies in the early stages after an ischaemic stroke revealed spontaneous activity in the affected muscles, today few data are available on the peripheral changes in later stages after a cerebrovascular event. The aim of this study was to detect electrophysiological signs that could indicate changes at the motor unit level occurring within a longer post-stroke period. Patients and methods - Forty-four patients who had developed hemiparesis after an ischaemic stroke in the area of the middle cerebral artery were involved in the study. Motor and sensory nerve conduction studies and electromyography were carried out on each side on six nerves and in five muscles respectively. Values between the affected and unaffected side were compared by statistical methods. Results - In patients with hemiparesis present for less then nine months, low M wave amplitudes, fibrillation potentials and an increased number of complex motor unit potentials were found on the affected side; in patients with symptoms present for more then nine months the mean duration and size index of the motor unit potentials in the paretic abductor digiti minimi muscle were increased. These data suggest a process of neurogenic type. The signs of distal axonal damage observed in the early period after stroke have been replaced later by chronic neurogenic changes. These changes could be the consequence of spinal motor neuron damage and axonal transport disturbance due to the loss of supraspinal trophic inputs. Conclusion - The correlation between the extent of electrophysiological changes and of the central motor deficit of the patient indicates the importance of delaying this process by appropriate rehabilitation procedures.]

Clinical Neuroscience

[Analysis of mental arithmetic task by the “minimum spanning tree” method]

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[Goals - In the present study basic arithmetic induced rearrangements in functional connections of the brain were investigated by using graph theoretical analysis what becomes increasingly important both in theoretical neuroscience and also in clinical investigations. Research questions - During mental arithmetic operations (working) memory plays an important role, but there are only a few studies in which an attempt was made to separate this effect from the process of arithmetic operations themselves. The goal of our study was to separate the neural networks involved in cognitive functions. Methods - As an attempt to clarify this issue the graph-theoretical “minimal spanning tree” method was used for the analysis of EEG recorded during task performance. The effects of passive viewing, number recognition and mental arithmetic on PLI based minimal spanning trees (MST) were investigated on the EEG in young adults (adding task: 17 subjects; passive viewing and number recognition: 16 subjects) in the θ (4-8 Hz) frequency band. Results - Occipital task relevant synchronization was found by using the different methods, probably related to the effect of visual stimulation. With respect to diameter, eccentricity and fraction of leafs different task-related changes were found. Discussion - It was shown that the task related changes of various graph indices are capable to identify networks behind the various relevant dominant functions. Thus the “minimal spanning tree” method is suitable for the analysis of the reorganization of the brain with respect to cognitive functions.]

Clinical Neuroscience

[Diagnosis of epilepsy]

JANSZKY József

[0.5-1% of the population suffers from epilepsy, while another 5% undergoes diagnostic evaluations due to the possibility of epilepsy. In the case of suspected epileptic seizures we face the following questions: Is it an epileptic seizure? The main and most frequent differential- diagnostic problems are the psychogenic non-epileptic seizures ("pseudo-seizures") and the convulsive syncope, which is often caused by heart disorders. Is it epilepsy? After an unprovoked seizure, the information on recurrence risk is an important question. The reoccurrence is more possible if a known etiological factor is present or the EEG shows epileptiform discharges. After an isolated epileptic seizure, the EEG is specific to epilepsy in 30-50% of cases. The EEG should take place within 24 hours postictally. If the EEG shows no epileptiform potentials, a sleep-EEG is required. What is the cause of seizures? Hippocampal sclerosis, benign tumors, and malformations of the cortical development are the most frequent causes of the focal epilepsy. Three potentially life-threatening conditions may cause chronic epilepsy: vascular malformations, tumors, and neuroinfections. The diagnosis in theses cases can usually be achieved by MRI, therefore, MRI is obligatory in all epilepsies starting in adulthood. The presence of epileptogenic lesion has a prognostic significance in treatment. If the MRI shows a circumscribed lesion then the pharmacological treatment will likely to be unsuccessful, while surgery may result in seizure freedom. The new and quantitative MRI techniques, such as volumetry, T2-relaxometry, MR-spectroscopy, and functional MRI play a growing role in the epilepsy diagnosis.]