Clinical Neuroscience

[PSYCHOPHYSIOLOGICAL AND CLINICAL ASPECTS OF THE EEG SYNCHRONIZATION RELATED TO COGNITIVE PROCESSES]

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

DECEMBER 10, 2005

Clinical Neuroscience - 2005;58(11-12)

[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.]

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[ELECTROMYOGRAPHY AT THE BEGINNING OF THE 21st CENTURY]

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[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.]

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[EVENT-RELATED EEG AND EVOKED POTENTIAL INVESTIGATIONS IN THE CLINICAL PRA]

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[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.]

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[The effect of hypertension and it’s therapy on cognitive performance of asymptomatic hypertensive patients]

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[The essential hypertension increases the risk of cognitive impairment even in symptom-free patients. Sixty, non-treated hypertensives were investigated (44±10.5 év) with nine pszichological tests, measuring the reaction time, attention, short and long-term memory, psychomotor speed etc. The results of nine tests were summarized and compared with those of age-matched control persons (n=98). All hypertensives had normal CT findings. The carotid intima-media-thickness, the arterial stiffness and the velocities in the middle cerebral arteries were also analyzed (with tilting table test). The sum of the results of cognitive tests was significantly worse than that of controls 14.8±7.1 vs. 27.8±5.5 p<0.0001. The results of intima-media thickness and stiffness measurements were also significantly worse compared with controls while the middle cerebral velocities did not differ. After one year antihypertensive therapy not only the improvement of blood pressure, intima-media thickness and stiffness values could be detected but also the the score of summarized cognitive tests improved (from 17.4±6.0 to 31.6±6.0 p<0.0001).]

Clinical Neuroscience

Late simultaneous carcinomatous meningitis, temporal bone infiltrating macro-metastasis and disseminated multi-organ micro-metastases presenting with mono-symptomatic vertigo – a clinico-pathological case reporT

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Although vertigo is one of the most common complaints, intracranial malignant tumors rarely cause sudden asymmetry between the tone of the vestibular peripheries masquerading as a peripheral-like disorder. Here we report a case of simultaneous temporal bone infiltrating macro-metastasis and disseminated multi-organ micro-metastases presenting as acute unilateral vestibular syndrome, due to the reawakening of a primary gastric signet ring cell carcinoma. Purpose – Our objective was to identify those pathophysiological steps that may explain the complex process of tumor reawakening, dissemination. The possible causes of vestibular asymmetry were also traced. A 56-year-old male patient’s interdisciplinary medical data had been retrospectively analyzed. Original clinical and pathological results have been collected and thoroughly reevaluated, then new histological staining and immunohistochemistry methods have been added to the diagnostic pool. During the autopsy the cerebrum and cerebellum was edematous. The apex of the left petrous bone was infiltrated and destructed by a tumor mass of 2x2 cm in size. Histological reexamination of the original gastric resection specimen slides revealed focal submucosal tumorous infiltration with a vascular invasion. By immunohistochemistry mainly single infiltrating tumor cells were observed with Cytokeratin 7 and Vimentin positivity and partial loss of E-cadherin staining. The subsequent histological examination of necropsy tissue specimens confirmed the disseminated, multi-organ microscopic tumorous invasion. Discussion – It has been recently reported that the expression of Vimentin and the loss of E-cadherin is significantly associated with advanced stage, lymph node metastasis, vascular and neural invasion and undifferentiated type with p<0.05 significance. As our patient was middle aged and had no immune-deficiency, the promoting factor of the reawakening of the primary GC malignant disease after a 9-year-long period of dormancy remained undiscovered. The organ-specific tropism explained by the “seed and soil” theory was unexpected, due to rare occurrence of gastric cancer to metastasize in the meninges given that only a minority of these cells would be capable of crossing the blood brain barrier. Patients with past malignancies and new onset of neurological symptoms should alert the physician to central nervous system involvement, and the appropriate, targeted diagnostic and therapeutic work-up should be established immediately. Targeted staining with specific antibodies is recommended. Recent studies on cell lines indicate that metformin strongly inhibits epithelial-mesenchymal transition of gastric cancer cells. Therefore, further studies need to be performed on cases positive for epithelial-mesenchymal transition.

Hypertension and nephrology

[About the care of patients with hyperuricaemia and gout]

[This consensus document is intended to provide guidance for the effective and efficient treatment of asymptomatic individuals with high uric acid levels and gout patients.]

Clinical Neuroscience

[What happens to vertiginous population after emission from the Emergency Department?]

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[Background – Dizziness is one of the most frequent complaints when a patient is searching for medical care and resolution. This can be a problematic presentation in the emergency department, both from a diagnostic and a management standpoint. Purpose – The aim of our study is to clarify what happens to patients after leaving the emergency department. Methods – 879 patients were examined at the Semmel­weis University Emergency Department with vertigo and dizziness. We sent a questionnaire to these patients and we had 308 completed papers back (110 male, 198 female patients, mean age 61.8 ± 12.31 SD), which we further analyzed. Results – Based on the emergency department diagnosis we had the following results: central vestibular lesion (n = 71), dizziness or giddiness (n = 64) and BPPV (n = 51) were among the most frequent diagnosis. Clarification of the final post-examination diagnosis took several days (28.8%), and weeks (24.2%). It was also noticed that 24.02% of this population never received a proper diagnosis. Among the population only 80 patients (25.8%) got proper diagnosis of their complaints, which was supported by qualitative statistical analysis (Cohen Kappa test) result (κ = 0.560). Discussion – The correlation between our emergency department diagnosis and final diagnosis given to patients is low, a phenomenon that is also observable in other countries. Therefore, patient follow-up is an important issue, including the importance of neurotology and possibly neurological examination. Conclusion – Emergency diagnosis of vertigo is a great challenge, but despite of difficulties the targeted and quick case history and exact examination can evaluate the central or peripheral cause of the balance disorder. Therefore, to prevent declination of the quality of life the importance of further investigation is high.]