bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of rTMS on an Auditory Oddball Task: A Pilot Study of Cortical Plasticity and the EEG
Authors: Cooper N.R. , Fitzgerald P.B. , Croft R.J. , Upton D.J. , Segrave R.A. , Daskalakis Z.J. , Kulkarni J. 
Published: February 2012

The objective of this study was to explore the effects of 1Hz repetitive transcranial magnetic stimulation (rTMS) applied to dorsal lateral prefrontal cortex (DLPFC) on both an EEG index of cortical excitation and inhibition, event-related desynchronization/synchronization (ERD/S) and on the P300 component of an auditory oddball-induced ERP. Eight normal participants received 15 minutes of 1Hz rTMS at 110% of the resting motor threshold to right DLPFC. ERD/S of alpha and beta bands was measured during an auditory oddball task immediately before and after stimulation. There was significantly less alpha desynchronization post-TMS, and this effect was widespread excepting posterior midline sites. No changes were found to oddball-P300 amplitudes or latencies. In conclusion, the findings of less alpha desynchronization post-TMS are compatible with notions of slow rTMS causing a decrease in cortical excitation.
Power Spectral Frequency and Coherence Abnormalities in Patients with Intractable Epilepsy and Their Usefulness in Long-Term Remediation of Seizures Using Neurofeedback
Authors: Walker Jonathan E. 
Published: February 2012

Medically intractable seizures appear to be highly correlated with focal slow activity (delta or theta). They also correlate highly with decreases in the coherence of theta. Normalization of focal slowing and of decreased theta coherence will probably be the neurofeedback approaches most likely to decrease or eliminate seizures in future cases. Neurofeedback has been used for over 35 years to reduce the incidence and severity of seizures. With power training to decrease theta and increase the sensorimotor rhythm (12–15 Hz), an average of 82% of patients experienced a significant reduction in seizure frequency, and occasional remissions were seen. Recent improvements using QEEG to guide neurofeedback training have made it possible to eliminate seizures in most patients, even those with intractable seizures. Following our previous study in 2005, we report an additional 25 patients so treated. We also report an analysis of the frequency of QEEG abnormalities in this patient group. All of the intractable epileptic patients had one or more slow foci (excessive theta or delta compared with the normal database). One third had a relative deficiency of beta power. One fourth had a deficiency of absolute delta. Eighteen percent had excessive absolute alpha power, 18% had deficient absolute alpha power, 18% percent had excessive absolute beta power, and 18% percent had deficient absolute beta power. Hypocoherence of theta was found in 75%, and decreases in alpha coherence were noted in 42%. Hypocoherence of beta was found in 50%, and hypocoherence of delta was found in 25%. Increases in alpha coherence were noted in 33%. Seventeen percent had no coherence abnormalities. When most of the power and coherence abnormalities were normalized with neurofeedback training, all the patients became seizure-free; 76% no longer required an anticonvulsant for seizure control.
Source Analysis of Alpha Rhythm Reactivity Using LORETA Imaging with 64-Channel EEG and Individual MRI
Authors: Cuspineda E.R. , Machado C. , Virues T. , Martínez-Montes E. , Ojeda A. , Valdés P. A. , Bosch J. , Valdes L. 
Published: February 2012

Conventional EEG and quantitative EEG visual stimuli (close-open eyes) reactivity analysis have shown their usefulness in clinical practice; however studies at the level of EEG generators are limited. The focus of the study was visual reactivity of cortical resources in healthy subjects and in a stroke patient. The 64 channel EEG and T1 magnetic resonance imaging (MRI) studies were obtained from 32 healthy subjects and a middle cerebral artery stroke patient. Low Resolution Electromagnetic Tomography (LORETA) was used to estimate EEG sources for both close eyes (CE) vs. open eyes (OE) conditions using individual MRI. The t-test was performed between source spectra of the two conditions. Thresholds for statistically significant t values were estimated by the local false discovery rate (lfdr) method. The Z transform was used to quantify the differences in cortical reactivity between the patient and healthy subjects. Closed-open eyes alpha reactivity sources were found mainly in posterior regions (occipito-parietal zones), extended in some cases to anterior and thalamic regions. Significant cortical reactivity sources were found in frequencies different from alpha (lower t-values). Significant changes at EEG reactivity sources were evident in the damaged brain hemisphere. Reactivity changes were also found in the “healthy” hemisphere when compared with the normal population. In conclusion, our study of brain sources of EEG alpha reactivity provides information that is not evident in the usual topographic analysis.
Magnetic Resonance Spectroscopy Findings in Photosensitive Idiopathic Generalized Epilepsy
Authors: Aydin-Ozemir Zeynep , Terzibasioglu Ege , Altindag Ebru , Sencer Serra , Baykan Betul 
Published: February 2012

Studies investigating the pathophysiology of epileptic photosensitivity indicate variable involvement of particular brain regions. Our aim was to identify metabolic differences between photosensitive idiopathic generalized epilepsy (IGE) patients and nonphotosensitive IGE patients and normal healthy subjects by using Magnetic Resonance Spectroscopy (MRS). Fourteen patients diagnosed with photosensitive IGE were investigated. The control groups consisted of 14 age- and sex-matched healthy volunteers and 14 IGE patients without photosensitivity. MRS measurements of N-acetylaspartate (NAA), choline-containing compounds (Cho), creatine (Cr) were performed in the frontal and occipital cortex and the thalamus bilaterally using a stimulated echo acquisition mode (STEAM) technique with a voxel size of 20times20times20 mm. The values of the patients with IGE were compared with those of the normal controls and within subgroups according to the clinical variables by appropriate statistical tests. Photosensitive IGE patients showed significantly decreased concentrations of NAA in the right frontal lobe and left thalamus, decreased NAA/Cr ratio in left thalamus and significantly increased concentrations of Cho/Cr ratio in the right frontal lobe and NAA/Cr in the left occipital lobe when compared to normal controls. Furthermore, left occipital NAA concentration increased and left thalamus NAA/Cr ratios were decreased from the IGE patients without photosensitivity but without reaching statistical significance. Our results support previous MR studies suggesting an asymmetrical neuronal dysfunction in favor of the dominant occipital cortex and thalamus in photosensitive IGE patients.
Deep Brain Stimulation of Pedunculopontine Tegmental Nucleus (PPTg) Promotes Cognitive and Metabolic Changes: A Target-Specific Effect or Response to a Low-Frequency Pattern of Stimulation?
Authors: Stefani A. , Pierantozzi M. , Ceravolo R. , Brusa L. , Galati S. , Stanzione P. 
Published: February 2012

Deep brain stimulation (DBS) is a reliable treatment for advanced Parkinson's disease (PD) patients, but a possible risk of worsening cognitive functions, although modest, may postpone or halt DBS clinical indication. In a small cohort of PD patients we have pioneered the simultaneous implantation of both the subthalamic nucleus (STN) and the pedunculopontine tegmental nucleus (PPTg). Here we describe the cognitive test performance and the corresponding cortical metabolic activity, as assessed through 18-fluorodeoxyglucose (FDG)-positron emission tomography (PET), of these six PD patients tested in PPTg-ON vs- PPTg-OFF condition. PPTg-ON condition (at low frequency, 25 Hz) induced better performance in tests exploring both executive and attentive domains, which were coupled with an increased glucose utilization in prefrontal and frontal bilateral cortical areas, including both lateral (i.e., BA 9) and more antero-medial cortices (BA 25–32). Moreover, during PPTg-ON, a surprising increase of FDG consumption was also observed in the left ventral striatum. These data are consistent with the hypothesis of a positive effect of 25 Hz PPTg-DBS on PD patients' cognitive profile, probably due to a facilitatory effect exerted by PPTg on both associative and limbic pathways.
Quantitative Electroencephalographic Abnormalities in Fibromyalgia Patients
Authors: Hargrove Jeffrey B. , Bennett Robert M. , Simons David G. , Smith Susan J. , Nagpal Sunil , Deering Donald E. 
Published: February 2012

There is increasing acceptance that pain in fibromyalgia (FM) is a result of dysfunctional sensory processing in the spinal cord and brain, and a number of recent imaging studies have demonstrated abnormal central mechanisms. The objective of this report is to statistically compare quantitative electroencephalogram (qEEG) measures in 85 FM patients with age and gender matched controls in a normative database. A statistically significant sample (minimum 60 seconds from each subject) of artifact-free EEG data exhibiting a minimum split-half reliability ratio of 0.95 and test-retest reliability ratio of 0.90 was used as the threshold for acceptable data inclusion. FM subject EEG data was compared to EEGs of age and gender matched healthy subjects in the Lifespan Normative Database and analyzed using NeuroGuide 2.0 software. Analyses were based on spectral absolute power, relative power and coherence. Clinical evaluations included the Fibromyalgia Impact Questionnaire (FIQ), Beck Depression Inventory and Fischer dolorimetry for pain pressure thresholds. Based on Z-statistic findings, the EEGs from FM subjects differed from matched controls in the normative database in three features: (1) reduced EEG spectral absolute power in the frontal International 10–20 EEG measurement sites, particularly in the low- to mid-frequency EEG spectral segments; (2) elevated spectral relative power of high frequency components in frontal / central EEG measurement sites; and (3) widespread hypocoherence, particularly in low- to mid-frequency EEG spectral segments, in the frontal EEG measurement sites. A consistent and significant negative correlation was found between pain severity and the magnitude of the EEG abnormalities. No relationship between EEG findings and medicine use was found. It is concluded that qEEG analysis reveals significant differences between FM patients compared to age and gender matched healthy controls in a normative database, and has the potential to be a clinically useful tool for assessing brain function in FM patients.
Electrophysiological Characteristics of Seizure Clusters
Authors: Tripathi M. , Singh P.K. , Vibha D. , Choudhary N. , Garg A. , Bal C.S. , Sarkar C. , Bhatia R. , Padma M.V. , Gaikwad S. , Singh M.B. , Prasad K. , Chandra P.S. 
Published: February 2012

The phenomenon of temporal clustering of seizures is well known, but its effect on seizure localization has not been rigorously analyzed. The aim of our study was to assess electrophysiological localization during Video EEG (VEEG) monitoring in patients with intractable epilepsy demonstrating a cluster of seizures. The study was conducted on 203 intractable epilepsy patients, aged 2 to 60 years (19.96 ± 10.87). Patients with unilateral temporal lobe epilepsy having clusters were compared with patients not having clusters, and the effect of clustering on concordance was addressed. Fully consistent localization was observed in 116 patients, partially consistent localization in 18 patients, and inconsistent localization in 19 patients. ANOVA did not reveal any significant difference in these groups (p = 0.65). A total of 770 seizures recorded from 149 patients was analyzed for clustering effect. Clustering was present in 603/770 seizures pairs (78.31%). In the cluster group, 483 (80.09%) seizure pairs were concordant for seizure onset, while 98 (16.25%) were discordant and 22 (3.65%) were indeterminate. In the noncluster group, 134 (80.24%) seizure pairs were concordant for seizure onset, while 23 (13.77%) were discordant and 10 (5.98%) were indeterminate. The study found that cluster seizures occurring within an interseizure interval (ISI) less than 8 hours are independent and have the same localizing value as those seizures with longer ISIs.
Hemispheric Lateralization in Benign Focal Epilepsy in Childhood with Centrotemporal Spikes (BECTS)
Authors: Miziara C.S.M.G. , Manreza M.L.G. 
Published: February 2012

Benign focal epilepsy in childhood with centrotemporal spikes (BECTS) is one of the most common forms of epilepsy. In adults there is a higher percentage of lateralized epileptic discharges in the left cerebral hemisphere; however, in children this pattern does not seem to have the same distribution. The objective of this study was to evaluate the lateralization of interictal spikes in children with BECTS in relation to the sex of the child and the age of onset of epilepsy. We studied the electroencephalograms (EEGs) of 114 children with a clinical diagnosis of BECTS according to ILAE. The results obtained from two EEGs, performed at intervals of 6 and 12 months, were correlated with the age of onset of the epileptic seizures and the sex of the child. There was no association between the onset of epileptic seizures and the age of the child (p = 0.461). When we analyzed the relationship between laterality and sex we did not observe any difference in the first EEG (p = 0.767) results; however, in the results of the second EEG there was a difference (p = 0.002). In males, left and bilateral interictal spikes were predominant, and in females the right hemisphere showed predominant spikes and there were continuous spike-and-wave discharges during slow sleep (CSWSS). The analysis between laterality and a child's age did not show predominant interictal spikes in the hemispheres, except in males where there were predominant multifocal and generalized spikes, but not lateralization (p = 0.011). The conclusion was that in BECTS the lateralization of interictal spikes was not consistent as described in adult patients, but there was a slight left hemispheric predominance in boys and right hemispheric predominance in girls.
Noninvasive Multimodal Neuroimaging for Rasmussen Encephalopathy Surgery: Simultaneous EEG-fMRI Recording
Authors: Bravo E.R. Cuspineda , Iturria Y. , Praderes J.C. , Melie L. , Valdés P.A. , Virues T. , Machado C. , Urrutia L. Valdés 
Published: February 2012

Rasmussen syndrome is characterized by continuous partial seizures with progressive neurological/cognitive impairment. Currently the only effective treatment is surgery (hemispherectomy). The objective of our study is to detect the exact epileptogenic focus through the analysis of multimodal noninvasive and innocuous functional neuroimaging. The subject is a 5-year-old female patient with Rasmussen encephalopathy. Continuous and simultaneous electroencephalography-functional magnetic resonance imaging (EEG-fMRI) was record ed. The sources of background and paroxysmal activity of EEG were computed by low resolution electromagnetic tomography (LORETA). Image analysis (SPM: statistic parametric mapping) was obtained for the areas where statistically significant differences in the fMRI BOLD response were computed, and the results from both techniques were compared. The main source of paroxysmal activity by EEG analysis was found in the anterolateral left hemisphere, with a significant increase in absolute and relative energies of slow frequency bands (theta-delta): Z ≥ 3. The fMRI BOLD signal (basal vs. paroxysmal activity) was significantly different in the same region (t-test ≥ 2.39). The generators of propagated paroxysmal activity were found in similar areas for both techniques. In conclusion, simultaneous EEG-fMRI recording allows the analysis of two harmless functional neuroimaging techniques separately and together in the same time period. In our case, it allowed the accurate delineation of epileptogenic foci and areas of spread with high spatiotemporal resolution, which is crucial for epilepsy surgery.
The Yield of Preoperative Sequential Routine Scalp EEGs in Patients Who Underwent Anterior Temporal Lobectomy for Mesial Temporal Sclerosis
Authors: Dericioglu Nese , Colpak Ayse Ilksen , Ciger Abdurrahman , Saygi Serap 
Published: February 2012

Mesial temporal lobe epilepsy syndrome (MTLES) is the most common surgically remediable epileptic syndrome in adults. Its diagnosis is easy when clinical history is supported by positive laboratory findings. However, routine EEG may not be informative in some patients, thus delaying accurate diagnosis. Therefore, we sought to determine how often routine EEGs displayed epileptiform discharges pre-operatively in a group of patients who underwent surgery for MTLES. Retrospectively, we reviewed the outpatient EEG records of MTLES patients who underwent surgery at our epilepsy center between 1997–2008 and had at least one routine pre-operative EEG recording in our outpatient laboratory. For each patient, serial EEGs were coded as normal, displaying nonspecific abnormalities or lateralized and localized interictal epileptiform discharges. Seventy patients were included in the study. We reviewed 230 EEGs. In almost half of the patients (47.1%) all EEGs were normal or revealed nonspecific findings. In patients who had >1 EEG, almost 3 EEGs had to be recorded to detect the epileptiform discharges for the first time and 6.23 years were needed to accomplish this. Sleep deprivation considerably increased the yield. In summary, patients who have a clinical history suggesting MTLES may need at least 3 routine scalp EEG recordings (with at least one of them after sleep deprivation) to detect epileptiform abnormalities and it may take much time. Therefore, a single prolonged outpatient video-EEG monitoring or an overnight inpatient monitoring might be reasonable alternatives to serial EEGs.
EEG Complexity and Attentional Processes Related to Dissociative States
Authors: Bob Peter , Golla Megan , Epstein Phillip , Konopka Lukasz 
Published: February 2012

Reported findings indicate that attentional narrowing is related to decreased complexity and increased inhibition of neural assemblies. These findings suggest that analysis of electroencephalogram (EEG) complexity could present a useful method for research of attentional changes related to dissociation. To examine this model we used a case study to test the two hypotheses: (1) that successful anticonvulsant medication would result in dissociative symptom alleviation, improvement of inhibitory neural functions, and decreased EEG complexity, and (2) that cognitive conflict, related to aversive events in the patient's past experience, during reliving of a dissociative state would lead to greater allocation of attention and decreased EEG complexity. Three EEG studies recorded in the eyes closed non-drowsy state were performed: (1) at baseline, (2) post-induction of dissociative state, and (3) post-anticonvulsant medication following induction of dissociative state. A dissociative state was achieved following an interview regarding the patient's aversive past experiences through use of the Peritraumatic Dissociative Experiences Questionnaire (PDEQ). The patient's level of dissociation was measured using the Dissociative Experiences Scale-II (DES-II). The PDEQ interview and DES-II assessment were also used one hour following the oral consumption of an anticonvulsant medication (clonazepam 2mg). Analysis of the data revealed that complexity values (PD2) are significantly lower following the oral consumption of clonazepam (2mg) in the majority of EEG channels. Additionally, complexity during the reliving of a dissociative state was statistically significantly lower than both the baseline and post-medication conditions in all but two EEG channels. Results of the case study suggest that changes in attentional processes linked to dissociation are related to: (1) decreased complexity when attention is extremely focused because of attentional narrowing to the disturbing past experience, and (2) increased complexity during ordinary experiences when attention is less narrowly focused.
Asynchronous P300-Based Brain-Computer Interface to Control a Virtual Environment: Initial Tests on End Users
Authors: Aloise Fabio , Schettini Francesca , Aricò Pietro , Salinari Serenella , Guger Christoph , Rinsma Johanna , Aiello Marco , Mattia Donatella , Cincotti Febo 
Published: February 2012

Motor disability and/or ageing can prevent individuals from fully enjoying home facilities, thus worsening their quality of life. Advance s in the field of accessible user interfaces for domotic appliances can represent a valuable way to improve the independence of these persons. An asynchronous P300-based Brain-Computer Interface (BCI) system was recently validated with the participation of healthy young volunteers for environmental control. In this study, the asynchronous P300-based BCI for the interaction with a virtual home environment was tested with the participation of potential end-users (clients of a Frisian home care organization) with limited autonomy due to ageing and/or motor disabilities. System testing revealed that the minimum number of stimulation sequences needed to achieve correct classification had a higher intra-subject variability in potential end-users with respect to what was previously observed in young controls. Here we show that the asynchronous modality performed significantly better as compared to the synchronous mode in continuously adapting its speed to the users' state. Furthermore, the asynchronous system modality confirmed its reliability in avoiding misclassifications and false positives, as previously shown in young healthy subjects. The asynchronous modality may contribute to filling the usability gap between BCI systems and traditional input devices, representing an important step towards their use in the activities of daily living.
Evaluation of Maturation and Function of Visual Pathways in Neonates
Authors: Chayasirisobhon Sirichai , Gurbani Saumya , Chai Edward E. , Spurgeon Benjamin , Yu Luke , Bosu Sogba , Gurbani Suresh 
Published: February 2012

The purpose of our study was to establish the guidelines for interpreting neonatal flash visual-evoked potentials (FVEPs) by examining the correlation between maturation of the waveforms and conceptual age (CA). We retrospectively analyzed 220 consecutive neonatal FVEPs performed on premature and full-term infants. The CA of the participants ranged from 28 to 52 weeks. The FVEPs were categorized into 6 groups according to CA: 28 to 31+ weeks, 32 to 35+ weeks, 36 to 39+ weeks, 40 to 43+ weeks, 44 to 47+weeks, and 48 to 52 weeks. The data were analyzed in each group and compared among these 6 groups. The waveforms changed from 28 weeks to 52 weeks of CA. In the CA age range 28 to 31+ weeks N3 was well visualized, followed by P3. The morphology of P2 including both latency and amplitude became prominent starting from CA age range 32 to 35+ weeks. The triphasic waveform with clear negative-positive-negative components (N2-P2-N3) presented after 32 weeks. Mean P2 latencies decreased steadily with increasing age. Mean amplitudes of all waveforms (P2-N3 and N3-P3) varied except that of N2-P2 which increased steadily with CA. We conclude that FVEPs can be useful in the evaluation of maturation and function of the visual pathway in neonates. The FVEP is abnormal when the waveforms N3 and P3 are nondetectable in neonates at 28 weeks of CA or older; and when the waveform P2 is non-detectable, or has low amplitude or prolonged latency, in neonates at 36 weeks of CA or older.