Clinical Neuroscience



DECEMBER 10, 2005

Clinical Neuroscience - 2005;58(11-12)

[The author provides an overview on the value of evoked potential (EP) methods (VEP, SEP, BAEP, MEP) in the diagnosis and follow-up of various neurological diseases (multiple sclerosis, cerebrovascular disorders, degenerative diseases, coma, epilepsy, migraine) by reviewing the literature supported by his own clinical experience. While in the past EP was mainly used for establishing the diagnosis, recently, with the expansion of neuroradiology, it has gained a wider use in the assessment of the severity and extent of the pathologic process and especially in longitudinal follow-up. Its role in the diagnostic phase has diminished. In patients with multiple sclerosis the abnormality of the evoked potentials correlate better with the clinical state than with the MRI results. The method is also suitable to monitor the response to therapy. The importance of the EP tests is illustrated by several case demonstrations.]



Further articles in this publication

Clinical Neuroscience


RAJNA Péter, HIDASI Zoltán, WALDEMAR Szelenberger

[Considering the limits of the traditional EEG techniques the authors review the main methods and clinical importance of the event-related EEG investigations. According to methods, these can be classified into the spectral analysis of task-related, pre-task and post-task recordings as well as stimuluscontrolled measurements based on evoked potential techniques. The main results of clinical studies on the eventrelated EEG methods are summarized according to chief disease groups (Alzheimer’s disease, epilepsy, schizophrenia, Parkinson's disease, dyslexia, depression). The authors discuss the stimulus-dependent EEG discharges (P300, cognitive potential) in detail. They present the metaanalysis of 224 recent publications on human application of these methods. They analyze the involved scientific areas and the frequency by which these methods were applied in each. Following this, the results of 83 selected clinical studies are summarized. The frequency of the application of the various event-related EEG methods and the tested wave components and other parameters are listed. Finally a summary of the main clinical results is presented again by groups of diseases (schizophrenia, behavioral disorders, traumatic lesions, enuresis nocturna, depression, memory disturbance and dementia, drug effect). Finally, the potential perspectives and the limitations of the event-related EEG methods are briefly discussed.]

Clinical Neuroscience


MOLNÁR Márk, CSUHAJ Roland, CSIKÓS Dóra, HAMVAI Csaba, CZIGLER Balázs, BÁLINT Andrea, GAÁL Zsófia Anna

[The authors review the various forms of EEG-synchronization with special emphasis on the characteristics of the induced and enhanced rhythms. The suggested role of the various EEG frequency bands in the cognitive processes is demonstrated by examples from the literature. The relationship between linear and nonlinear electrophysiological complexity and EEG synchronization is analyzed, with a touch on the use of Omega-complexity and synchronization likelihood methods. In the present study the EEG recorded during adding and subtracting tasks was analyzed with the above methods. It was found that during the adding task the theta band increased in the frontal area, which may be related to activation of working memory processes. Mapping the scalp-distribution of synchronization likelihood also confirmed increased synchronization in the frontal area in addition to which increased values were found in the left temporo-parietal area. The analysis of linear and nonlinear EEG synchronization associated with cognitive processing is suitable to explore the task-related and region specific features of these events.]

Clinical Neuroscience



[This review article is concerned with the role of electromyography (EMG) in the clinical diagnostic work. After a summary on the developmental history of electromyography, the most important EMG methods are presented. The modern quantitative EMG methods are sensitive and accurate thus providing important information in the evaluation of various neurological diseases, particularly in the diagnosis of neuromuscular disorders. The EMG examinations are useful tool for the clinician only if the applied methods are carefully chosen and properly performed and the rules of interpretation are strictly followed.]

Clinical Neuroscience


ARÁNYI Zsuzsanna

[Transcranial magnetic stimulation (TMS) is a relatively new technique that allows painless activation of cortical motor neurons. In the clinical setting, TMS is primarily used for the investigation of the corticospinal tract in various neurological diseases, being especially useful in the detection of subclinical dysfunction. In addition to the motor cortex, TMS can be applied to examine other structures inaccessible to electrical stimulation, such as the canalicular portion of the facial nerve. In healthy individuals, TMS can be utilized to monitor excitability changes of the motor system in various situations and muscles, providing valuable information to the understanding of the physiology of motor control. Furthermore, TMS can be used to explore interhemispheric connections as well as intracortical inhibitory and excitatory processes both in health and disease. Finally, with the help of TMS cortical maps of the representation areas of muscles can be constructed, giving insight to both short and long-term cortical plasticity and to the reorganisation of the motor cortex following damage to the brain or acquisition of new motor skills]

Clinical Neuroscience


KISS Gábor

[Nerve conduction studies are fundamental elements of the neurophysiological investigation of neuromuscular diseases. They provide information on peripheral nerve function. Knowledge of the biological and technical basis of the method is essential for the clinician to understand the place of nerve conduction testing in the diagnostic process. A characteristic feature of the nerve fibers is their ability to conduct electrical potentials. This conductivity changes in pathologic circumstances; therefore, the patient's nerve conduction data may be important if a neuromuscular disorder is suspected. The electrical activity spreading along the nerve fibres can be detected with special techniques and instruments. To perform an examination, a stimulator, a high quality amplifier and a computer with various accessories are necessary. The examination is usually carried out by surface stimulation and recording electrodes and requires some cooperation. By supramaximal stimuli all nerve fibers in the peripheral nerve are activated, and their summated activity is recorded bipolarly. For technical reasons the procedures for the motor and the sensory nerve conduction measurements are somewhat different, but their principles are similar. A number of parameters, such as the latency, the amplitude, the area and the shape of the evoked potentials are analyzed. These parameters are influenced by many biological (age, gender, body height, etc.), physical (such as limb temperature) and technical factors. The results are compared with the reference data. Nerve conduction studies may help distinguish between normal and diseased nerve function. The latter has two main categories; axonal lesion and demyelinisation. Axonal lesion is characterized by relatively normal conduction velocity and lower than normal amplitude of the potentials. Demyelinisation is almost the opposite with long latencies, slow conduction velocity and relatively spared potential amplitudes. Nerve conduction studies help differentiate between these two forms. Abnormalities found by nerve conducion measurement may reflect the severity of the disease. Repeated studies are suitable for quantitative follow-up. The anatomical, physiological, pathophysiological and technical details are discussed below. The characteristic neurographic findings of various diseases are also summarized.]

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Related contents

Clinical Neuroscience

Management of bone metabolism in epilepsy

UÇAN TOKUÇ Ezgi Firdevs , FATMA Genç, ABIDIN Erdal, YASEMIN Biçer Gömceli

Many systemic problems arise due to the side effects of antiepileptic drugs (AEDs) used in epilepsy patients. Among these adverse effects are low bone mineral density and increased fracture risk due to long-term AED use. Although various studies have supported this association with increased risk in recent years, the length of this process has not been precisely defined and there is no clear consensus on bone density scanning, intervals of screening, and the subject of calcium and vitamin D supplementation. In this study, in accordance with the most current recommendations, our applications and data, including the detection of possible bone mineralization disorders, treatment methods, and recommendations to prevent bone mineralization disorders, were evaluated in epilepsy patients who were followed up at our outpatient clinic. It was aimed to draw attention to the significance of management of bone metabolism carried out with appropriate protocols. Epilepsy patients were followed up at the Antalya Training and Research Hospital Department of Neurology, Epilepsy Outpatient Clinic who were at high risk for osteoporosis (use of valproic acid [VPA] and enzyme-inducing drugs, using any AED for over 5 years, and postmenopausal women) and were evaluated using a screening protocol. According to this protocol, a total of 190 patients suspected of osteoporosis risk were retrospectively evaluated. Four patients were excluded from the study due to secondary osteoporosis. Of the 186 patients who were included in the study, 97 (52.2%) were women and 89 (47.8%) were men. Prevalence of low bone mineral density (BMD) was 42%, in which osteoporosis was detected in 11.8% and osteopenia in 30.6% of the patients. Osteoporosis rate was higher at the young age group (18-45) and this difference was statistically significant (p=0.018). There was no significant difference between male and female sexes according to osteoporosis and osteopenia rates. Patients receiving polytherapy had higher osteoporosis rate and lower BMD compared to patients receiving monotherapy. Comparison of separate drug groups according to osteoporosis rate revealed that osteoporosis rate was highest in patient groups using VPA+ carbamazepine (CBZ) (29.4%) and VPA polytherapy (19.4%). Total of osteopenia and osteoporosis, or low BMD, was highest in VPA polytherapy (VPA+ non-enzyme-inducing AED [NEID]) and CBZ polytherapy (CBZ+NEID) groups, with rates of 58.3% and 55.1%, respectively. In addition, there was no significant difference between drug groups according to bone metabolism markers, vitamin D levels, and osteopenia-osteoporosis rates. Assuming bone health will be affected at an early age in epilepsy patients, providing lifestyle and diet recommendations, avoiding polytherapy including VPA and CBZ when possible, and evaluating bone metabolism at regular intervals are actions that should be applied in routine practice.

Clinical Neuroscience

Effects of valproate, carbamazepine and levetiracetam on Tp-e interval, Tp-e/QT and Tp-e/QTc ratio


Aim - To evaluate P-wave dispersion before and after antiepileptic drug (AED) treatment as well as to investigate the risk of ventricular repolarization using the Tpeak-Tend (Tp-e) interval and Tp-e/QT ratio in patients with epileptic disorder. Methods - A total of 63 patients receiving AED therapy and 35 healthy adults were included. ECG recordings were obtained before and 3 months after anti-epileptic treatment among patients with epilepsy. For both groups, Tp-e and Tp-e/QT ratio were measured using a 12-lead ECG device. Results - Tp-e interval, Tpe/QT and Tp-e/QTc ratios were found to be higher in the patient group than in the control group (p<0.05, for all), while QTmax ratio was significantly lower in the patient group. After 3 months of AED therapy, significant increases in QT max, QTc max, QTcd, Tp-e, Tp-e/QT, and Tp-e/QTc were found among the patients (p<0.05). When the arrhythmic effects of the drugs before and after treatment were compared, especially in the valproic acid group, there were significant increases in Tp-e interval, Tp-e/QT and Tp-e/QTc values after three months of treatment (p<0.05). Carbamazepine and levetiracetam groups were not statistically significant in terms of pre- and post-treatment values. Conclusions - It was concluded that an arrhythmogenic environment may be associated with the disease, and patients who received AED monotherapy may need to be followed up more closely for arrhythmia.

Clinical Neuroscience

[Personalised epilepsy treatment]


[Epilepsy is one of the most common chronic neurological disease in childhood. Patients with epilepsy – even with so-called benign epilepsy – need medication for years. During this time, children go through a very big change, not only gaining weight and height, but also changing hormonal and metabolic processes. Maturation processes in different brain areas also take place at different rates depending on age. All of these should be considered when preparing a therapeutic plan. In everyday practice after the diagnosis of epilepsy, the applied drug is most often selected based on the shape and type of seizure. However, a number of other factors need to be considered when designing a therapeutic strategy: 1. efficacy (form of epilepsy, type of seizure), 2. age, gender, 3. pharmacological properties of the drug, 4. adverse drug reaction profile, 5. lifestyle (community), figure (skinny, corpulent, obese), 6. other comorbidities (nutrition, behavioral and learning problems, circulatory disorders, kidney or liver disease), 7. expected interactions with other drugs already used, 8. genetics, 9. other aspects (drug registration and prescription rules). The purpose of this article is to help to decide which antiepileptic drugs are expected to have the least side effects in a particular child with different comorbidities and which medications should be avoided if possible.]

Clinical Neuroscience

[Decisional collisions between evidence and experience based medicine in care of people with epilepsy]


[Background – Based on the literature and his long-term clinical practice the author stresses the main collisions of evidence and experience based medicine in the care of people with epilepsy. Purpose – To see, what are the professional decisions of high responsibility in the epilepsy-care, in whose the relevant clinical research is still lacking or does not give a satisfactory basis. Methods – Following the structure of the Hungarian Guideline the author points the critical situations and decisions. He explains also the causes of the dilemmas: the lack or uncertainty of evidences or the difficulty of scientific investigation of the situation. Results – There are some priorities of experience based medicine in the following areas: definition of epilepsy, classification of seizures, etiology – including genetic background –, role of precipitating and provoking factors. These are able to influence the complex diagnosis. In the pharmacotherapy the choice of the first drug and the optimal algorithm as well as the tasks during the care are also depends on personal experiences sometimes contradictory to the official recommendations. Same can occur in the choice of the non-pharmacological treatments and rehabilitation. Discussion and conclusion – Personal professional experiences (and interests of patients) must be obligatory accessories of evidence based attitude, but for achieving the optimal results, in some situations they replace the official recommendations. Therefore it is very important that the problematic patients do meet experts having necessary experiences and also professional responsibility to help in these decisions. ]

Clinical Neuroscience

Evaluation of anxiety, depression and marital relationships in patients with migraine


Aim - The aim of this study was to evaluate the frequency and characteristics of attacks in patients with migraine, to determine the effects of anxiety or depressive symptoms, and to evaluate the marital relationships of patients with migraine. Method - Thirty patients who were admitted to the neurology outpatient clinic of our hospital between July 2018 and October 2018 and were diagnosed with migraine according to the 2013 International Headache Society (IHS) diagnostic criteria were included in this cross-sectional study. Age, sex, headache frequency and severity, depressive traits, marital satisfaction and anxiety status were examined. We used the Beck Depression Inventory (BDI), State-Trait Anxiety Inventory (STAI), Maudsley Marital Questionnaire (MMQ) and Visual Analogue Scale (VAS) for measuring relevant parameters. Results - The mean severity of migraine pain according to VAS scale was 6.93 ± 1.41 and the mean number of migraine attacks was 4.50 ± 4.24. The mean BDI score of the patients was 12.66 ± 8.98, the mean MMQ-M score was 19.80 ± 12.52, the mean MMQ-S score was 13.20 ± 9.53, the mean STAI-state score was 39.93 ± 10.87 and the mean STAI-trait score was 45.73 ± 8.96. No significant correlation was found between age, number of migraine attacks, migraine duration, migraine headache intensity, and BDI, STAI and MMQ scores (p>0.05). But there was a positive correlation between MMQ-S and scores obtained from the BDI and STAI-state scales (p<0.05). Conclusion - In this study more than half of the migraine patients had mild, moderate or severe depression. A positive correlation was found between sexual dissatisfaction and scale scores of depression and anxiety.