Clinical Neuroscience

[Synchronized, oscillatory brain activity in visual perception]

BRAUNITZER Gábor

SEPTEMBER 30, 2008

Clinical Neuroscience - 2008;61(09-10)

[The present study investigates one of the most promising developments of the brain-mind question, namely the possible links between synchronized oscillatory brain activity and certain (visual) perceptual processes. Through a review of the relevant literature, the author introduces the reader to the most important theories of coherent perception (’binding‘), and makes an attempt to show how synchronization of EEG-registrable oscillatory activities from various frequency bands might explain binding. Finally, a number of clinical problems are also mentioned, regarding which the presented theoretical framework might deserve further consideration.]

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Clinical Neuroscience

[European Association of Young Neurologists and Trainees]

SZTRIHA László

[European Association of Young Neurologists and Trainees 2008;61(09-10)]

Clinical Neuroscience

[Editorial comment]

RAJNA Péter

[Editorial comment 2008;61(09-10)]

Clinical Neuroscience

[Antiepileptic drugs as mood stabilizers: what did we learn from the epileptology?]

RAJNA Péter

[Author summarizes the practical aspects of psychiatric application of mood stabilizing antiepileptic drugs. He observes how to transfer experiences taken from the “epileptological” practice into the psychiatric care of bipolar patients. He shortly demonstrates the relevant information on the mechanisms of action, controversies and possible clinical effects influenced by the seizure inhibiting effect of the concerning molecules. By the opinion of the author the clinical importance of pharmacokinetic parameters are underestimated in the psychiatric practice. Therefore - as an original approach in the literature - he summarizes the detailed clinical indications of serum level measurements of antiepileptic drugs applied in psychiatry as mood stabilizers. The therapeutic experiences in epilepsy added a lot of practices for the most effective dosing, building, tapering and exchange of the mood stabilizer antiepileptics. Drug interactions (appear among the psychotropic drugs or with the commonly used medicines). As in any chronic therapies the main condition of patient's compliance is the lacking or very mild presence of the applied therapy. The paper discusses the most frequently occurring and drug-specific side effects in table forms. Using the term of “relative therapeutic potential” the need of balance between the efficacy (influenced by the choice and dosing) and the tolerance are pointed. Rules of application can change significantly in special populations like in pregnancy, obesity, chronic diseases or in chronic comorbide states and in case of polytherapy. As for the special therapeutic effects, the experiences are not completed even in group of antiepileptics: we have larger and more favorable knowledge on the traditional drugs (carbamazepine and valproates) and on lamotrigine (from the newer generation) but promising but not enough information exists on the newest antiepileptic molecules. Further targeted studies are needed for the identification and positioning of antiepileptic drugs in the palette of mood stabilizing pharmacotherapy and for the definition of evidence based, individually tailored and lifelong applied highly effective combinations of the mood stabilizing pharmacotherapy containing antiepileptic agents.]

Clinical Neuroscience

[The impact of prolonged hunger strike: clinical and laboratory aspects of twenty-five hunger strikers]

D Kirbas, N Sutlas, DY Kuscu, N Karagoz, O Tecer, U Altun

[Background - Hunger strike is a very serious entity which may lead to severe diseases and death. Aims - The aim of this study is to document the clinical, neurophysiological, neuroradiological, and neuropsychological aspects of prolonged hunger strike. Material and method - We investigated the clinical and laboratory characteristics of 25 hungerstrikers hospitalized during refeeding process. One sample t-test, independent samples t-test, Mann-Whitney and Pearson correlation tests were used for statistical analyses. Results - Twelve of them had a continuous hunger strike ranging between 190-366 days. The other 13 had quitting intervals for various reasons with a continuous hunger ranging between 65-265 days with a total hunger duration of 153-382 days. The mean loss of body mass index (BMI) was 40.98±9.3%. Imbalance, sleep disorders, somatosensory disturbances, and adynamia were the most common complaints. At admission, one third experienced ophtalmoparesis, about half of them had paresis, one quarter had truncal ataxia. At discharge 16% had persistant ophtalmoparesis and 36% nystagmus. Only four patients (16%) could walk independently. There was no serious MRI, EEG findings. Most prominent EMG findings were the decrease in median and sural nerve cnap, median and fibulary cmap, and fibulary ncv values. They showed mild impairment in MMTS and most of them had attention deficit and frontal type memory impairment. Conclusion - It can be concluded that vitamin B intake, independent of the quantity and timing, lowers the morbidity and mortality of hunger strikers.]

Clinical Neuroscience

[Paraneoplastic chronic demyelinating neuropathy and lambert-eaton myasthenic syndrome associated with multiple anti-neural antibodies and small-cell lung cancer]

RÓZSA Csilla, VINCENT Angela, ARÁNYI Zsuzsanna, KOVÁCS G. Gábor, KOMOLY Sámuel, ILLÉS Zsolt

[Lambert-Eaton myasthenic syndrome (LEMS) developed in a patient with presumed chronic inflammatory demyelinating polyneuropathy (CIDP) and negative chest CT. Since antibodies against both Hu and voltage-gated calcium channel (VGCC) were detected, repeated chest CT was performed, which eventually showed a pulmonary mass lesion. Biopsy revealed small cell lung cancer (SCLC) indicating the importance of repeated chest CT in LEMS even when an existing autoimmune-like disease and negative CT may suggest an autoimmune origin. This is the first report of paraneoplastic CIDP and LEMS associated with anti-Hu, anti-VGCC and SCLC.]

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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

[EEG-based cerebral networks in 14 neurological disorders]

DÖMÖTÖR Johanna, CLEMENS Béla, CSÉPÁNY Tünde, EMRI Miklós, FOGARASI András, HOLLÓDY Katalin, PUSKÁS Szilvia, FEKETE Klára, KOVÁCS Attila, FEKETE István

[Background - Brain networks have not been systematically investigated yet in most neurological disorders. Purpose - To investigate EEG functional connectivity (EEGfC) networks in 14 neurological disorders. Patients - Potentially eligible patients were collected from clinical and EEG databases. All the available clinical data and EEG records were critically revised. All the patients who suffered of a single neurological disorder (out of the 14) and had a good quality EEG recording entered the study. Confoundig factors as comorbidity and CNS-active drug effects were eliminated as far as possible. EEG analysis - Three minutes of resting-state, waking EEG activity were selected for analysis. Current source density (CSD) values were computed for 2394 cortical voxels by Low Resolution Electromagnetic Tomography (LORETA). Thereafter, Pearson correlation coefficients were computed between all pairs of 23 cortical regions of interest (ROI) in each hemisphere (LORETA Source Correlation, LSC software). Computation was carried out for conventional EEG broad bands and very narrow bands (1 Hz bandwidth) between 1 and 25 Hz as well. Correlation coefficients of each group were statistically compared to our normative EEG (LSC) database by two-talied t-tests. Bonferroni-corrected p<0.05 values were accepted as statistically significant, and were graphically displayed as topographical networks. Results and conclusion - Group-specific networks were demonstrated. However, non-specific networks, charasteristic for most groups, were detected as well. Common finding were: decreased connectivity in the alpha band and increased connectivity in the delta, theta bands and upper-beta band. Decreased alpha-band connectivity presumably reflected primary lesional effects and on the other hand, non-specific vulnerability of “rich club connections”. Increased connectivity in the slow bands presumably indicated adaptive-compensatory activity of brain homeostasis. ]

Clinical Neuroscience

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Clinical Neuroscience

[Spectral, phase-synchronization, and graph theoretical EEG changes related to mental arithmetics]

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[During mental arithmetic operations working memory playsan important role, but there are only few studies in which anattempt was made to separate this effect from the process ofarithmetics per se. In this study the effects of arithmetic onthe EEG of young adults (14 participants, six of themwomen, mean age 21.57 years, SD: 2.62) was investigatedduring a subtraction task in the θ(4-8 Hz) frequency band.Besides the power density spectrum analysis phasesynchrony based on recently developed graph theoreticalmethods were used and strength of local connections (clustercoefficient; C) and global interconnectedness of network(characteristic path length; L) were determined. Before thearithmetic task passive viewing (control situation) and anumber recognition paradigms were used. During the arith-metic task compared to the control situation significantlyincreasing phase synchrony and C values were found. L wassignificantly shorter (F(2, 26)=818.77, p<0.0001) only dur-ing the arithmetic task: this fact and the former two resultsimply that the network topology shifted towards the “smallworld” direction. Our findings concerning regionaldifferences confirm those reported earlier in the literature:compared to the control condition significant task-relatedincrease was found in C values in the parietal areas [moreexplicitly in the left side, (F(1, 13)=7.2020, p=0.0188)],which probably corresponds to stronger local connectionsand more synchronized (sub)networks. During the task con-dition significantly increased θband power; (F(1,13)=7.9708, p=0.0144) and decreased L values werefound in the left frontal region compared to the right side(F(1, 13)=6.0734, p=0.0284), which can also be interpret-ed as an indicator of optimized network topology ofinformation processing.]

Clinical Neuroscience

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