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Search for the word below: EEG frequency spectrum
Number of hits: 300
Hypertension and nephrology
DECEMBER 12, 2019
SEPTEMBER 30, 2019
[Despite of the symptoms of vertigo have been known since thousands of years, it was evident by the research of the pioneer scientists of the 19th century (Flourens, Ménière, Breuer and others) that dizziness can also be attributed to inner ear disfunctions. The discovery of the vestibulo-ocular reflex was an important milestone (Endre Hőgyes, 1884). The vestibulo-ocular reflex stabilizes images on the retina by rotating the eyes at the same speed but in the opposite direction of head motion. The milestone discovery of Hőgyes by stimulating individual labyrinth receptors and recording the activity of eye muscles were verified by János Szentágothai in 1950. Low-frequency lesions of the angular vestibulo-ocular reflex can be investigated by caloric test (Robert Bárány,1906), high-frequency lesions by head impulse test (Gabor Michael Halmagyi and Ian Stewart Curthoys, 1988).]
SEPTEMBER 30, 2019
[Aims - Overview of the new data about the strong link of sleep and epilepsy and conjoining cognitive impairment. Methods - Search for relevant references and summary of our own research activity on the topic. Results - Strong interrealtionship exists between epilepsy and plastic brain functions (memory processing and synaptic homeostasis) and the working modes of NREM sleep. In the most frequent childhood and adult epilepsy networks responsible for plastic functions can be derailed to an epileptic level of excitability, and suffer a transitory or permanent epileptic transformation. Exampling on the three big epilepsies: absence epilepsy; medial temporal lobe epilepsy; and childhood idiopathic focal age dependent epilepsy spectrum we demonstrate the most important features of this epileptic transformation. The association of cognitive impairment to certain sleep dependent epilepsies gains explanation by the epilepsy caused interference with slow wave decline (ICFE) and memory consolidation (MTLE) during NREM sleep. This paper serves also to introduce the concept of sleep dependent system epilepsies. Conclusions - We provide evidences about shared mechanisms among sleep related epilepsies being the derailment of sleep plastic funcions toward exaggerated excitability determined by the inherent possibilities of the signal transduction properties. ]
JULY 30, 2019
Aim - In this study, we aimed to examine the risk factors, topographic features and stroke mechanisms of acute ischemic unilateral infarcts of thalamus. Methods - Patient with isolated thalamic infarct and those with posterior cerebral artery (PCA) infarction who were admitted to our hospital between January 2014 and January 2017 with acute unilateral thalamic infarction (TI) were included in this study (isolated thalamic infarction/ isolated TI; thalamic and posterior cerebral artery infarction/PCA+TI). Demographic characteristics and vascular risk factors of the patients were determined. Thalamic infarct areas were recorded topographically as anterior, posteromedial, ventrolateral, posterolateral, more than one area, and variant areas. Stroke mechanism was determined according to the criteria of „Trial of Org 10172 in Acute Stroke Treatment” (TOAST). Patients with isolated TI and PCA TI were compared according to risk factors, stroke mechanism and infarct topography. Results - Forty-three patients with a mean age of 63.3 ± 14.5 years were included in the study. Twenty-eight patients (60.1%) were found to have isolated TI and the remaining 15 patients (34.9%) had PCA+TI. 32.1% of patients with isolated TI had sensory symptoms on presentation, and 60% of patients with PCA-TI had sensorimotor symptoms. The mean age, the mean score on National Institutes of Health Stroke Scale (NIHSS) and the mean frequency of atrial fibrillation were higher in PCA+TI patients than in isolated-TI patients (p: 0.04, p: 0.004, p: 0.02 respectively). 32.6% of the patients had ventrolateral, 30.2% had posteromedial involvement. Ventrolateral topography was seen in 46.7% of the PCA+TI patients, while posteromedial topography was seen in 39.3% of the isolated-TI patients. 53.6% of the isolated-TI had small vessel disease etiology, while 40% of the PCA+TI had cardioembolic etiology, and the other 40% had large artery atherosclerosis. Conclusion - Our study showed that the most ommon stroke mechanism in patients with thalamic infarction is the small vessel disease. Isolated TI and PCA+TI patients differ in terms of etiologic mechanism and infarct topography. Variant territorial involvement and multiple area involvements can be quite common in thalamic infarcts.
JULY 30, 2019
Introduction - Restless Leg Syndrome (RLS) is a disease, primarily composed of sensational symptoms, caused by the urge to move lower extremities especially at night, and characterized by undesired feelings of the legs. Decreasing of the dopaminergic effect at night is thought to be responsible from these symptoms. RLS patients suffer from low quality of sleep affecting their daily life activities even causing socio-economic loss. Although RLS is a common and treatable disease, it can not be diagnosed easily due to the variability of symptoms. Aim - The purpose of this study is to determine the frequency of RLS among health workers and to define the disease causing factors. Method - A questionnaire was applied to 174 randomly selected health workers at Baskent University Medical Faculty (KA17/285). The demographic information, history of illnesses or usage of drugs, socioeconomic status, working hours and daytime sleepiness were questioned. Included in the questionnaire were diagnostic criteria for RLS, frequency assessment scale, and survey of sleep quality. We used “the diagnostic criteria of international RLS working group” for the diagnosis, and “Pittsburgh sleep quality index survey” to determine the quality of sleep. Reliability and validity studies were performed on both tests. Results - A significant relationship between socio-economic status and RLS was found (p<0.05) as an increase of RLS frequency in parallel with decreased socio-economic status. RLS was found to be common among health workers. We suggest that health workers should be checked regularly, and they should be informed about the disease in order to raise an awareness and hence increase their quality of life.
Lege Artis Medicinae
MAY 20, 2019
[Antibiotic therapy might alter gut microbiome. The consequence of that is dysbiosis with or without immediate overt clinical manifestation. The beneficial effect of rifaximin, a non-absorbable broad spectrum antibiotic, in gastrointestinal and hepatic disorders is known for a long time. According to recent data rifaximin has not only antibiotic but also anti-inflammatory and, within antibiotics, a unique special eubiotic effect as well. It modulates the gut microbiome, restores eubiosis through increasing beneficial species’ count while not disturbing diversity.]
MAY 30, 2019
Purpose - Methylation is a key epigenetic modification of DNA and regarding its impact on epilepsy, it is argued that “DNA methylation may play an important role in seizure susceptibility and maintenance of the disorder”. DNA methylation status of KCC2 (SCL12A5) and NKCC1 (SCL12A2) associated with refractory temporal lobe epilepsy was investigated in our study. Materials and methods - Thirty-eight patients with temporal lobe epilepsy (TLE) who were diagnosed by video EEG monitoring and 32 healthy control subjects were included in the study. Twenty-three patients in TLE group were men and the remaining 15 were women. Among them, 27 had unilateral temporal focus (9 with right; 18 with left) and 11 patients had bilateral TLE. We analyzed promoter region methylation status of the KCC2 (SCL12A5) and NKCC1 (SCL12A2) genes in the case and control groups. Gene regions of interest were amplified through PCR and sequencing was accomplished with pyro-sequencing. Results - We found a significant relationship between TLE and methylation on the NKCC1. However, there was no association between TLE and methylation on the KCC2 gene. Also, we found no association between right or left and unilateral or bilateral foci of TLE. There was no relationship between TLE and methylation on the NKCC1and KCC2 genes in terms of mesial temporal sclerosis in cranial MRI, head trauma or febrile convulsions. Conclusion - The methylation of NKCC1 can be a mechanism of refractory temporal lobe epilepsy. There are limited findings about DNA methylation in TLE. Therefore, further studies with large sample sizes are necessary.
MAY 30, 2019
Background and purpose - Migraine is a risk factor for ischemic stroke in women of childbearing ages. Previous researches revealed a higher prevalence of hyperhomocysteinemia in migraineurs. Possible differences on the frequencies of hyperhomocysteinemia between migraine with aura and migraine without aura could contribute the established variances in stroke risk between these migraine types. Therefore, we aimed to search if the frequency of hyperhomocysteinemia was different between these subtypes of migraine or not. Methods - We analyzed the findings of serum homocysteine levels in female migraineurs of 16-49 years old who admitted to our outpatient clinic. Results - Homocysteine level was elevated in 13.3% of study population. There were not any significant differences on median serum homocysteine levels between migraine with aura (8.0 mikromol/L) and without aura (8.5 mikromol/L). (p=0.426) The frequencies of hyperhomocysteinemia were also similar (9.1% versus 16.7%, respectively; p=0.373). Correlation analyses did not reveal any linear correlation between ages and homocysteine levels either in group of migraine with aura or in group of migraine without aura (p=0.417 and p=0.647, respectively). Similarly, any linear correlation between disease ages and homocysteine levels either in group of migraine with aura or in group of migraine without aura was not detected (p=0.359 and p=0.849, respectively). Conclusion - The median serum homocysteine levels and the frequencies of hyperhomocysteinemia are similar between migraine with aura and without aura in women of childbearing ages. Therefore, the variances on stroke risk ratios between these types of migraine are probably not originated from the differences of serum homocysteine status.
Lege Artis Medicinae
MARCH 20, 2019
[The process of atherosclerosis nowadays plays an important role in the health care not just as a major cause of the most common cardiovascular diseases which lead to death, but also as a major factor in the loss of age-related elasticity in the blood vessels. Over the past two decades, large studies have shown that the treatment of high cholesterol levels can reduce the frequency of cardiovascular events and death and have confirmed the ability to reduce the already existing atherosclerotic plaque, which is almost unique in pharmacotherapy. Using lipid lowering therapy, if we do it properly, we can not only prevent vascular events, but can also cure atherosclerosis. Currently there are three drug groups (statins, ezetimibe and PCSK9- inhibitors), which have complete evidence that their use can reduce the number of cardiovascular events and plaque regression can be achieved. Despite many convincing clinical trials, lipid-lowering therapy is on the cardiovascular prevention palette in the just tolerated or forced applied category. In order to take advantage of its potentials at an appropriate level, as doctors, we have to approach to it by considering its importance. We should communicate to our patients that it’s about a life-long treatment, which not only can reduce the possibility of cardiovascular events, but also can slow down the aging process of the arteries. ]
MARCH 30, 2019
Objective - to investigate the neurophysiological basis of secondary generalization of partial epileptic seizures. Patients and methods - inter-ictal, resting-state EEG functional connectivity (EEGfC) was evaluated and compared: patients with exclusively simple partial seizures (sp group) were compared to patients with simple partial and secondary generalized seizures (spsg group); patients with exclusively complex partial seizures (cp group) were compared to patients with cp and secondary generalized seizures (cpsg group); the collapsed sp+cp group (spcp) was compared to those who had exclusively secondary generalized seizures (sg group). EEGfC was computed from 21-channel waking EEG. 3 minutes of waking EEG background activity was analyzed by the LORETA Source Correlation (LSC) software. Current source density time series were computed for 23 pre-defined cortical regions (ROI) in each hemisphere, for the 1-25 Hz very narrow bands (1 Hz bandwidth). Thereafter Pearson correlation coefficients were calculated between all pairs of ROI time series in the same hemisphere. Z-scored correlation coefficients were compared at the group level (t-tests and correction for multiple comparisons by local false discovery rate, FDR). Results - Statistically significant (corrected p<0.05) EEGfC differences emerged at specific frequencies (spsg > sg; cpsg > cp), and at many frequencies (sg > spcp). The findings indicated increased coupling between motor cortices and several non-motor areas in patients with partial and sg seizures as compared to patients with partial seizures and no sg seizures. Further findings suggested increased coupling between medial parietal-occipital areas (structural core of the cortex) and lateral hemispheric areas. Conclusion - increased inter-ictal EEGfC is associated with habitual occurrence of secondary generalized seizures.
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