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EEG Recordings (eeg + recording)

Distribution by Scientific Domains

Medical Sciences	84%
Life Sciences	6%
2 Other Domains	10%

Selected Abstracts

Academic performance in children with rolandic epilepsy

DEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 5 2008
P Piccinelli MD
The aim of this study was to investigate the frequency of reading, writing, and calculation disabilities in children with typical rolandic epilepsy (RE) and healthy control children. We also aimed to define the possible electroclinical markers of specific cognitive dysfunctions in RE. School abilities were evaluated and compared in 20 children (eight males, 12 females; mean age 10y 3mo [SD 1y 7mo]; range 7y 9mo-12y 9mo) consecutively diagnosed with typical RE, and a group of 21 healthy controls (nine males, 12 females; mean age 10y 4mo [SD 1y 8mo]; range 7y 6mo-13y 3mo). All the children received standardized neuropsychological tests. For each patient an exhaustive seizure diary was kept and all the sleep electroencephalogram (EEG) recordings were reviewed. Specific difficulties with reading, writing, and calculation (diagnosed according to the criteria of the Diagnostic and Statistical Manual of Mental Disorders, 4th edition) were found in nine out of 20 children with RE and two out of 21 healthy controls (,2=0.01). The specific learning disabilities in the RE group were correlated with a marked increase in epileptiform discharges during sleep (,2=0.02) and an early onset of epilepsy (,2=0.02). Our findings suggest that seizure onset before age 8 years and epileptiform discharges (more than 50% of the sleep EEG recording) in several tracings over more than a year are relevant markers for identifying patients at risk of developing academic difficulties. [source]

EEG Characteristics Related to Educational Impairments in Children with Benign Childhood Epilepsy with Centrotemporal Spikes

EPILEPSIA, Issue 11 2007
Joost Nicolai
Summary Purpose: Learning and behavioral difficulties often occur in benign childhood epilepsy with centrotemporal spikes (BCECTS). In recent years, several electroencephalogram (EEG) characteristics have been related to the occurrence of learning and behavioral problems. Methods: From 28 children medical, school and psychological reports were present and children were rated according to a 4-point scale for educational and behavioral impairment (Part 1). Thirty 24-h EEG recordings were reanalyzed for spike frequency, the presence of atypical EEG criteria, and the presence of a nondipole spike. EEGs were scored during wakefulness, first hour of sleep and whole night sleep (minus the first hour of sleep) separately (Part 2). Results: The presence of I: an intermittent slow-wave focus during wakefulness, II: a high number of spikes in the first hour of sleep (and during whole night sleep), and III: multiple asynchronous bilateral spike-wave foci in the first hour of sleep correlates significantly with a sum score , 3 which indicates a complicated course with educational or behavioral impairment. It is sufficient to analyze an EEG during wakefulness and a sleep EEG for only the first hour of sleep instead of a whole night recording to demonstrate those EEG criteria. Conclusions: On basis of our reanalysis we can possibly conclude that the aforementioned EEG characteristics correlate with educational impairments, and that analysing an EEG recording during wake and the first hour of sleep is sufficient to look adequately for those EEG criteria in children with BCECTS. [source]

Adding Video Recording Increases the Diagnostic Yield of Routine Electroencephalograms in Children with Frequent Paroxysmal Events

EPILEPSIA, Issue 5 2005
Nathan Watemberg
Summary:,Purpose: To report on the usefulness of adding video recording to routine EEG studies of infants and children with frequent paroxysmal events. Methods: We analyzed the efficacy of this diagnostic means during a 4-year period. The decision whether to add video recording was made by the pediatric EEG interpreter at the time of the study. Studies were planned to last between 20 and 30 min, and, if needed, were extended by the EEG interpreter. For most studies, video recording was added from the beginning of EEG recording. In a minority of cases, the addition of video was implemented during the first part of the EEG test, as clinical events became obvious. In these cases, a new study (file) was begun. The success rate was analyzed according to the indications for the EEG study: paroxysmal eye movements, tremor, suspected seizures, myoclonus, staring episodes, suspected stereotypias and tics, absence epilepsy follow-up, cyanotic episodes, and suspected psychogenic nonepileptic events. Results: Video recording was added to 137 of 666 routine studies. Mean patient age was 4.8 years. The nature of the event was determined in 61 (45%) of the EEG studies. Twenty-eight percent were hospitalized patients. The average study duration was 26 min. This diagnostic means was particularly useful for paroxysmal eye movements, staring spells, myoclonic jerks, stereotypias, and psychogenic nonepileptic events. About 46% of 116 patients for whom cognitive data were available were mentally retarded. EEG with added video recording was successfully performed in all 116 cases and provided useful information in 29 (55%) of these 53 patients. Conclusions: Adding video recording to routine EEG was helpful in 45% of cases referred for frequent paroxysmal events. This technique proved useful for hospitalized children as well as for outpatients. Moreover, it was successfully applied in cognitively impaired patients. Infants and children with paroxysmal eye movements, staring spells, myoclonic jerks, stereotypias, and pseudoseizures especially benefited from this diagnostic means. Because of its low cost and the little discomfort imposed on the patient and his or her family, this technique should be considered as a first diagnostic step in children with frequent paroxysmal events. [source]

A Kindling Model of Pharmacoresistant Temporal Lobe Epilepsy in Sprague,Dawley Rats Induced by Coriaria Lactone and Its Possible Mechanism

EPILEPSIA, Issue 4 2003
Ying Wang
Summary: ,Purpose: The aim of this study was to develop a new animal model of pharmacoresistant temporal lobe epilepsy (TLE) by repeated intramuscular injection of Coriaria lactone (CL) at subthreshold dosages and to explore the mechanisms that might be involved. Methods: Healthy male Sprague,Dawley rats (n = 160) were randomized into four groups during the kindling process: three groups (n = 50 for each group) received CL injection at subthreshold dosages (1.25, 1.5, and 1.75 mg/kg, respectively), and ten received normal saline (NS) injection as a control group. The maximal human adult dosage of carbamazepine (CBZ), valproate (VPA), and phenytoin (PHT) was administered as monotherapy to different groups of kindled rats for 1 month (n = 20 for each group). Changes in EEG recording, seizure number, intensity (expressed as grade 1,5 according to Racine stage), and duration, including spontaneous seizures during different interventions, were compared. The expression of P-170, a multiple drug resistance gene (MDR1) encoding P-glycoprotein, was measured in brain samples from different groups of experimental rats by using an image analysis and measurement system (ImagePro-Plus 4.0). Results: A total of 70 (46.7%) rats were fully kindled with a median of 15 (seven to 20) CL injections. Electrocorticogram (ECoG) including hippocampal (EHG) monitoring revealed the temporal lobe origins of epileptiform potentials, which were consistent with the behavioral changes observed. Spontaneous seizures occurred with frequency and diurnal patterns similar to those of human TLE. The antiepileptic drugs (AEDs) tested lacked a satisfactory seizure control. The maximal P-170 expression was in the kindled rats with AED treatment; the next highest was in the kindled rats without AED intervention. Nonkindled SD rats with CL injection also had increased P-170 expression compared with control SD rats. Conclusions: The study provided a simple and stable animal TLE kindling model with pharmacoresistant properties. The pharmacoresistance observed in the kindled rats to CBZ, VPA, and PHT at maximal human adult dosages together with the increased P-170 expression was a distinct feature of this model. This model might be used in further investigations of the mechanisms involved in pharmacoresistant TLE and for developing new AEDs. [source]

Cardiovascular Regulation through Hypothalamic GABAA Receptors in a Genetic Absence Epilepsy Model in Rat

EPILEPSIA, Issue 2 2002
Rezzan Gülhan Aker
Summary: ,Purpose: ,-Aminobutyric acid (GABA) plays a vital role in both central cardiovascular homeostasis and pathogenesis of epilepsy. Epilepsy affects autonomic nervous system functions. In this study, we aimed to clarify the role of GABAA receptors in hypothalamic cardiovascular regulation in a genetically determined animal model of absence epilepsy. Methods: Nonepileptic Wistar rats and genetic absence epilepsy rats from Strasbourg (GAERS) were instrumented with a guide cannula for drug injection and extradural electrodes for EEG recording. After a recovery period, iliac arterial catheters were inserted for direct measurement of mean arterial pressure and heart rate. Bicuculline, a GABAA -receptor antagonist, was injected into the dorsomedial (DMH) or posterior (PH) hypothalamic nuclei of nonepileptic control rats or GAERS. Blood pressure, heart rate, and EEG recordings were performed in conscious unrestrained animals. Results: Bicuculline injections into the hypothalamus produced increases in blood pressure and heart rate of both control rats and GAERS. The DMH group of GAERS showed a twofold increase in the blood pressure and the heart rate compared with those of control rats. Pressor responses to bicuculline, when microinjected into the PH, were similar in the nonepileptic animals and GAERS. Conversely, the amplitude of tachycardic responses to the administration of bicuculline into the PH was significantly higher in GAERS compared with those of control rats. Conclusions: The bicuculline-induced increases in blood pressure and heart rate were more prominent when given in the DMH of GAERS. These results indicate an increased GABAA receptor,mediated cardiovascular response through the DMH in conscious rats with absence epilepsy. [source]

Movement-Induced Focal Motor Seizures and Choreoathetosis As- sociated with Nonketotic Hyperglycemia: A Case Report

EPILEPSIA, Issue 2000
Hisashi Tanaka
Case Report: We report the case of a diabetic woman who developed right-sided reflex seizures and bilateral choreoathetosis during an episode of nonketotic hyperglycemia. The patient was a 67-year-old woman with a 14-year history of HCV-related liver cirrhosis who experienced polydipsia and polyuria in January 1998. She began to have episodes of abnormal hyperkinetic movements of the right upper extremity and tonic-clonic seizures in the right arm triggered by voluntary movements of right or bilateral arms in the beginning of March 1998. The seizures increased in frequency and consequently left her disabled. She was admitted to our hospital with complaints of these abnormal motor phenomena on March 9, 1998. Neurological examinations revealed that she was alert, well-oriented, and that cranial nerve functions were normal. Slight motor weakness of the right upper limb and deep tendon hyporeflexes were observed in all extremities. Sensations and cerebellar functions were intact. Choreic or athetotic involuntary movements were seen in the bilateral upper limbs and neck. These involuntary movements were increased by voluntary movement or posturing of the upper limbs. The focal tonic-clonic seizures were easily triggered by voluntary movements such as knotting a cord. This seizure suddenly began by tonic movements in the right upper limb and gradually progressed to the right hemi-face and neck without loss of consciousness. The average duration of seizures was about one minute. The laboratory data demonstrated mild leukocytopenia, thrombocytopenia, hepatic dysfunction, and hyperglycemia without ketosis. Fasting blood glucose was 41 I mg/dl, and HbAlc was 14.5%. Blood ammonia was within normal levels. Cranial CT revealed no abnormalities. Brain MRI on T I-weighted images demonstrated bilateral high signal intensity in the putamen. An interictal EEG revealed a symmetrical slow background activity of 7,8 Hz. An ictal EEG recording showed a 2.5 4 Hz irregular sharp and slow wave discharge in the bilateral frontal-central regions. Treatment with carbamazepine was ineffective for the seizures. However, the seizures completely disappeared after the administration of insulin on March 17. Under good control of the hyperglycemia, the abnormal involuntary movements decreased gradually and then completely disappeared; the patient became neurologically asymptomatic by March 30. The follow-tip EEG demonstrated 9-Hz alpha background activity without any epileptic discharges. Conclusions: Nonketotic hyperglycemia has been rarely reported to cause stimulus-induced seizures or hyperkinetic involuntary movements such as hemichorea-ballism. To our knowledge, this is the first reported case of both induced seizures and involuntary movements simultaneously caused by hyperglycemia. Movement-induced seizures and choreoathetoid movements in this patient can be considered to result from transiently-increased activity in the basal ganglia and/or cerebral cortex associated with metaholic disorders. [source]

Studying the satisfaction of patients on the outcome of an aesthetic dermatological filler treatment

JOURNAL OF COSMETIC DERMATOLOGY, Issue 4 2008
Lúcia Helena Fávaro De Arruda MD
Summary Background, Many factors contribute to extend productive life in the modern world. Competition makes people worry about physical appearance, mostly in respect to facial and skin aging. This has motivated new developments in cosmetic dermatology and the need of evaluating patient satisfaction with the new proposed treatments. Poll questionnaire has been used for such evaluation, and the analysis of the electroencephalogram (EEG) mapping obtained while the patient answers the satisfaction questionnaire may render the results less subjective. Objectives, The purpose of this paper is to study the satisfaction of a group of 33 women (mean age, 44 years) treated with hyaluronic acid filling of nasolabial folding or lips, combining the EEG brain mapping and questionnaire techniques. Methods, At the third month of evaluation, two networked personal computers were used for the EEG recording and for presenting the patient with a questionnaire about her well-being feeling; self-evaluation of her face; her satisfaction with the results of the aesthetic treatment; how the family, friends, and people at work evaluated the result of the treatment; and her decision to repeat the treatment and to recommend it to friends and family. Results, Poll results showed that patients were feeling well and were satisfied with the results of the aesthetic treatment. Furthermore, the regression EEG mappings showed patients to be satisfied with their appearance and with the treatment involving similar brain areas. Conclusion, Patients decided to undergo the treatment because they were already considering it (54%) or because they were dissatisfied with their lips or nasolabial folding (52%). The fact that the treatment was free of charge solidified the decision. Patients consider themselves as good-looking and they wanted to preserve such a condition. [source]

Diurnal variations in the waking EEG: comparisons with sleep latencies and subjective alertness

JOURNAL OF SLEEP RESEARCH, Issue 3 2000
Lafrance
Daytime measures of sleep latency and subjective alertness do not correlate with one another, suggesting that they assess different aspects of alertness. In addition, their typical diurnal variations show very different time courses. Quantitative analysis of the waking electroencephalogram (EEG) has been proposed as an objective measure of alertness, but it is not clear how it compares with other measures. In this study, the waking EEG was measured in the daytime to determine the presence of diurnal variations in the activity of standard frequency bands and to compare these variations with the temporal patterns typical of sleep propensity and subjective alertness. Alertness was evaluated in four men and 12 women, aged 19,33 y. Assessments were conducted every 2 h, from 10.00 to 24.00, in the following order: a visual analogue scale of alertness, a waking EEG recording and a sleep latency test. The waking EEG was recorded with eyes open. For each recording session, 32,60 s of artefact-free signals were selected from the C3/A2 derivation, then subjected to amplitude spectral analysis. Four EEG frequency bands showed significant diurnal variations: delta, theta, sigma and beta1. None of these variations showed a significant correlation with the temporal patterns of sleep latencies or subjective alertness. At the individual level, however, theta band activity increased when subjective alertness decreased, suggesting that the theta band can be used to monitor variations in alertness in a given individual, even at the moderate levels of sleepiness experienced during the daytime. [source]

Neurophysiological techniques to assess pain in animals

JOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 5 2006
J. C. MURRELL
Neurophysiological techniques are widely applied to animals, both in the search as a monitor for adequacy of anaesthesia, and studies to assess the efficacy of analgesic agents. Laboratory animals have been extensively used in models to investigate pain in man. However a substantial number of studies have also used neurophysiological techniques to increase knowledge of pain in specific animal species, with the aim of improving animal welfare. This review provides an overview of neurophysiological techniques involving the brain that have been used in the assessment of pain in animals. An explanation of the methodology of EEG recording, with particular emphasis on veterinary studies, is given. Neurophysiological models developed to assess pain in different species are described, and their relevance to advancements in animal welfare or best clinical practice indicated. [source]

Cannabis-induced propriospinal myoclonus

MOVEMENT DISORDERS, Issue 6 2004
Dora A. Lozsadi D.Phil
Abstract We report on a case of a 25-year-old woman with clusters of myoclonus induced by a single exposure to inhaled cannabis. Investigations excluded a structural abnormality of the spine. Multi-channel surface EMG with parallel frontal EEG recording confirmed the diagnosis of propriospinal myoclonus. © 2004 Movement Disorder Society [source]

The electrophysiological correlates sustaining the retrieval of face,name associations: An ERP study

PSYCHOPHYSIOLOGY, Issue 4 2004
F. Joassin
Abstract An ERP study on 9 healthy participants was carried out to temporally constrain the neural network proposed by Campanella et al. (2001) in a PET study investigating the cerebral areas involved in the retrieval of face,name associations. Three learning sessions served to familiarize the participants with 24 face,name associations grouped in 12 male/female couples. During EEG recording, participants were confronted with four experimental conditions, requiring the retrieval of previously learned couples on the basis of the presentation of name,name (NN), face,face (FF), name,face (NF), or face,name (FN) pairs of stimuli. The main analysis of this experiment consisted in the subtraction of the nonmixed conditions (NN and FF) from the mixed conditions (NF and FN). It revealed two main ERP components: a negative wave peaking at left parieto-occipital sites around 285 ms and its positive counterpart recorded at left centro-frontal electrodes around 300 ms. Moreover, a dipole modeling using three dipoles whose localization corresponded to the three cerebral areas observed in the PET study (left inferior frontal gyrus, left medial frontal gyrus, left inferior parietal lobe) explained more than 90% of the variance of the results. The complementarity between anatomical and neurophysiological techniques allowed us to discuss the temporal course of these cerebral activities and to propose an interactive and original anatomo-temporal model of the retrieval of face,name associations. [source]

Evaluation of head-only and head-to-tail electrical stunning of farmed eels (Anguilla anguilla, L.) for the development of a humane slaughter method

AQUACULTURE RESEARCH, Issue 5 2002
E Lambooij
Abstract The overall objective was to evaluate the suitability of electronarcosis as a stunning method for farmed eels. In the first experiment the minimum electrical current needed to induce a general epileptiform insult by head-only stunning was assessed. The individual eels (n = 40) with a live weight of 700,800 g were fixed in a specially designed re-strainer. The EEG (electroencephalogram) and ECG (electrocardiogram) recordings, observation of behaviour and responses to pain stimuli were used to assess unconsciousness, insensibility and cardiac function. The applied current of 150, 200 or 250 V, 50 Hz, AC was delivered via scissor-model stunning tongs for approximately 1 s. A general epileptiform insult was observed in 31 eels for which a successful EEG recording was obtained, using 255 ± 4 V, 545 ± 32 mA, for 1.2 ± 0.2 s. The general epileptiform insult as measured on the EEG was characterized by a tonic/clonic phase and an exhaustion phase. The behaviour showed one phase: tonic cramps alternated by clonic ones. The heart rate was 22 ± 8 beats min,1 (n = 23) prior to stunning. After stunning the ECG revealed fibrillation. In the second experiment the behaviour of seven individual eels able to move freely in water was observed after head-only stunning (250 V). Two phases were distinguished. Limited tonic and clonic cramps combined with backward swimming were followed by heavy clonic cramps combined with unco-ordinated movements such as jumping out of the water. A distinct exhaustion phase was not observed in all animals. In the third experiment a head-to-tail electrical method was examined in 15 eels for rendering the eels unconscious and insensitive prior to slaughter. They were stunned by applying 253 V for 3 s followed by 50 V for 5 min. In the fourth experiment nine eels were head-only stunned with 260 V for 1 s immediately followed by 50 V for 5 min applied from head to tail. Results obtained in these two experiments were similar. After stunning no brain activity and no responses to pain stimuli on the EEG were observed and the ECG showed ventricular extra systolae. It was observed that it might take 60 ± 25 min or longer for a complete recovery. It can be concluded that for effective electrical stunning of eels with a weight of 700,800 g an average current of 545 ± 32 mA (at approximate 250 V, 50 Hz AC) is needed. In this case, within a confidence level of 95% at least 91% of the eels are effectively stunned (n = 31). Therefore, it is recommended to increase the minimum current for an effective stun in practice to 600 mA. Further research is needed to determine the conditions to induce permanent unconsciousness and insensibility of the eels to protect the animals at slaughter. [source]

Cortical auditory dysfunction in benign rolandic epilepsy

EPILEPSIA, Issue 6 2008
Dana F. Boatman
Summary Purpose: To evaluate cortical auditory function, including speech recognition, in children with benign rolandic epilepsy (BRE). Methods: Fourteen children, seven patients with BRE and seven matched controls, underwent audiometric and behavioral testing, simultaneous EEG recordings, and auditory-evoked potential recordings with speech and tones. Speech recognition was tested under multiple listening conditions. Results: All participants demonstrated normal speech recognition abilities in quiet, as well as normal peripheral and subcortical auditory function. BRE patients performed significantly worse than controls when speech recognition was tested under adverse listening conditions, including background noise. Five BRE patients who were impaired on two or more tests had centrotemporal spiking on awake EEG. There were no significant group differences in the latency or amplitude of early N100 cortical responses to speech or tones. Conversely, the mismatch negativity, a preattentive index of cortical processing that is elicited passively, was absent or prolonged for speech, but not tones, in BRE patients as compared to controls. Discussion: Children with BRE demonstrated specific speech recognition impairments. Our evoked potential findings indicate that these behavioral impairments reflect dysfunction of nonprimary auditory cortex and cannot be attributed solely to attention difficulties. A possible association between auditory impairments and centrotemporal spiking (>1/min) on awake EEG was identified. The pattern of speech recognition impairments observed is a known risk factor for academic difficulties in school-age children. Our results underscore the importance of comprehensive auditory testing, using behavioral and electrophysiological measures, in children with BRE. [source]

Autosomal dominant nocturnal frontal lobe epilepsy with a mutation in the CHRNB2 gene

EPILEPSIA, Issue 3 2008
Fernando Díaz-Otero
Summary Autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE; MIM 600513) has been associated with mutations in the genes coding for the alfa-4 (CHRNA4), beta-2 (CHRNB2), and alpha-2 (CHRNA2) subunits of the neuronal nicotinic acetylcholine receptor (nAChR) and for the corticotropin-releasing hormone (CRH). A four-generation ADNFLE family with six affected members was identified. All affected members presented the clinical characteristics of ADNFLE. Interictal awake and sleep EEG recordings showed no epileptiform abnormalities. Ictal video-EEG recordings showed focal seizures with frontal lobe semiology. Mutation analysis of the CHRNB2 gene revealed a c.859G>A transition (Val287Met) within the second transmembrane domain, identical to that previously described in a Scottish ADNFLE family. To our knowledge, this is the third family reported presenting a mutation in CHRNB2. The clinical phenotype appears similar to that described with mutations in CHRNA4, suggesting that mutations in these two subunits lead to similar functional alterations of the nAChR. [source]

Dense array EEG: Methodology and new hypothesis on epilepsy syndromes

EPILEPSIA, Issue 2008
Mark D. Holmes
Summary Dense array EEG is a method of recording electroencephalography (EEG) with many more electrodes (up to 256) than is utilized with standard techniques that typically employ 19,21 scalp electrodes. The rationale for this approach is to enhance the spatial resolution of scalp EEG. In our research, dense array EEG is used in conjunction with a realistic model of head tissue conductivity and methods of electrographic source analysis to determine cerebral cortical localization of epileptiform discharges. In studies of patients with absence seizures, only localized cortical regions are involved during the attack. Typically, absences are accompanied by "wave,spike" complexes that show, both at the beginning and throughout the ictus, repetitive cycles of stereotyped, localized involvement of mainly mesial and orbital frontal cortex. Dense array EEG can also be used for long-term EEG video monitoring (LTM). We have used dense array EEG LTM to capture seizures in over 40 patients with medically refractory localization-related epilepsy, including both temporal and extra temporal cases, where standard LTM failed to reveal reliable ictal localization. One research goal is to test the validity of dense array LTM findings by comparison with invasive LTM and surgical outcome. Collection of a prospective series of surgical candidates who undergo both procedures is currently underway. Analysis of subjects with either generalized or localization-related seizures suggest that all seizures, including those traditionally classified as "generalized," propagate through discrete cortical networks. Furthermore, based on initial review of propagation patterns, we hypothesize that all epileptic seizures may be fundamentally corticothalamic or corticolimbic in nature. Dense array EEG may prove useful in noninvasive ictal localization, when standard methods fail. Future research will determine if the method will reduce the need for invasive EEG recordings, or assist in the appropriate placement of novel treatment devices. [source]

EEG source localization in focal epilepsy: Where are we now?

EPILEPSIA, Issue 2 2008
Chris Plummer
Summary Electroencephalographic source localization (ESL) by noninvasive means is an area of renewed interest in clinical epileptology. This has been driven by innovations in the computer-assisted modeling of dipolar and distributed sources for the investigation of focal epilepsy; a process fueled by the ever-increasing computational power available to researchers for the analysis of scalp EEG recordings. However, demonstration of the validity and clinical utility of these mathematically derived source modeling techniques has struggled to keep pace. This review evaluates the current clinical "fitness' of ESL as applied to the focal epilepsies by examining some of the key studies performed in the field, with emphasis given to clinical work published in the last five years. In doing so, we discuss why ESL techniques have not made an impact on routine epilepsy practice, underlining some of the current problems and controversies in the field. We conclude by examining where ESL currently sits alongside magnetoencephalography and combined EEG-functional magnetic resonance imaging in the investigation of focal epilepsy. [source]

Autosomal Dominant Inheritance of Centrotemporal Sharp Waves in Rolandic Epilepsy Families

EPILEPSIA, Issue 12 2007
Bhavna Bali
Summary Purpose: Centrotemporal sharp (CTS) waves, the electroencephalogram (EEG) hallmark of rolandic epilepsy, are found in approximately 4% of the childhood population. The inheritance of CTS is presumed autosomal dominant but this is controversial. Previous studies have varied considerably in methodology, especially in the control of bias and confounding. We aimed to test the hypothesis of autosomal dominant inheritance of CTS in a well-designed family segregation analysis study. Methods: Probands with rolandic epilepsy were collected through unambiguous single ascertainment. Siblings in the age range 4,16 years underwent sleep-deprived EEG; observations from those who remained awake were omitted. CTS were rated as present or absent by two independent observers blinded to the study hypothesis and subject identities. We computed the segregation ratio of CTS, corrected for ascertainment. We tested the segregation ratio estimate for consistency with dominant and recessive modes of inheritance, and compared the observed sex ratio of those affected with CTS for consistency with sex linkage. Results: Thirty siblings from 23 families underwent EEG examination. Twenty-three showed evidence of sleep in their EEG recordings. Eleven of 23 recordings demonstrated CTS, yielding a corrected segregation ratio of 0.48 (95% CI: 0.27,0.69). The male to female ratio of CTS affectedness was approximately equal. Conclusions: The segregation ratio of CTS in rolandic epilepsy families is consistent with a highly penetrant autosomal dominant inheritance, with equal sex ratio. Autosomal recessive and X-linked inheritance are rejected. The CTS locus might act in combination with one or more loci to produce the phenotype of rolandic epilepsy. [source]

EEG Characteristics Related to Educational Impairments in Children with Benign Childhood Epilepsy with Centrotemporal Spikes

ICTAL EEG Fast Activity in West Syndrome: From Onset to Outcome

EPILEPSIA, Issue 11 2007
Ferruccio Panzica
Summary Purpose: To characterize the fast EEG activities associated with infantile spasms in West syndrome, and their value in predicting the recurrence and localization of late seizures. Methods: We selected 23 infants who were followed for at least 2 years. Selected EEG recordings underwent autospectra, coherence, and phase analyses in order to assess the changes during follow-up. Results: Short discharges of fast-rhythms (331 ± 190 ms) with a lateralized onset were detected in 18 of the 23 infants (78.3%). There were no significant differences in the parameters characterizing ICTAL beta-activity (frequency, duration, inter-hemispheric coherence, or transfer time) between the infants with or without seizure recurrence. However, beta-discharges with a consistent location formed part of the ICTAL EEG in all 10 infants with seizure recurrence, but only in eight (61.5%) of those who remained seizure-free (SF) (p < 0.05). In all but one of the infants experiencing seizure recurrence, the ICTAL discharges associated with the late seizures apparently originated from the same hemisphere as that involved at the beginning of the spasm-associated beta-activity, although the precise location varied. Conclusions: Spectral, coherence and phase analyses detected spasm-associated runs of lateralized beta-rhythms in many of our infants with West syndrome. This ICTAL pattern significantly correlated with seizure recurrence. The consistent lateralization of the ICTAL EEG events associated with both the early spasms and late seizures suggests that EEG beta-activities should be considered as indicating local cortical dysfunction in infants who fail to respond to early treatment and often progress toward severe epilepsy. [source]

Neuroimaging and Neurophysiology of Periodic Lateralized Epileptiform Discharges: Observations and Hypotheses

EPILEPSIA, Issue 7 2007
Giridhar P. Kalamangalam
Summary:,Purpose: We assessed neuroimaging lesion type and distribution in patients with periodic lateralized epileptiform discharges (PLEDs), with a view to identifying electrographic differences between PLEDs associated with differing lesion locations. Our observations led us to consider a conceptual synthesis between PLEDs and periodic complexes (PCs). Methods: Retrospective review of acute neuroimaging results (CT/MRI) on patients identified to have EEG PLEDs, for the period 1999,2003 (n = 106). Blinded classification of original EEG recordings. Results: Neuroimaging abnormalities were classified as acute or chronic cortical, or acute or chronic subcortical. Seven out of 106 scans were classified nonlesional. Overall ,70% of scans had cortical abnormalities, whether acute or chronic; ,23% had subcortical abnormalities. "Cortical" PLEDs were significantly longer in duration (p < 0.05) and more variable in morphology (p < 0.01) than "subcortical" PLEDs. Conclusions: Structural brain disease commonly, but not invariably, underlies PLEDs; lesion type is spatiotemporally variable. Cortical and subcortical PLEDs have distinct EEG signatures. There is evidence that these may relate to mechanisms for other pathological large-scale oscillatory brain synchronies (e.g., PCs). [source]

Quantitative EEG Asymmetry Correlates with Clinical Severity in Unilateral Sturge-Weber Syndrome

EPILEPSIA, Issue 1 2007
Laura A. Hatfield
Summary:,Purpose: Sturge-Weber syndrome (SWS) is a neurocutaneous disorder with vascular malformations of the skin, brain, and eye. SWS results in ischemic brain injury, seizures, and neurologic deficits. We hypothesized that a decrease in quantitative EEG (qEEG) power, on the affected side, correlates with clinical severity in subjects with SWS. Methods: Fourteen subjects had 16-channel scalp EEG recordings. Data were analyzed using fast Fourier transform and calculation of power asymmetry. Blinded investigators assigned scores for clinical neurological status and qualitative assessment of MRI and EEG asymmetry. Results: The majority of subjects demonstrated lower total power on the affected side, usually involving all four frequency bands (delta, theta, alpha, and beta). qEEG asymmetry correlated strongly with neurologic clinical severity scores and MRI asymmetry scores. qEEG data generally agreed with the MRI evidence of regional brain involvement. In MRI-qEEG comparisons that did not agree, decreased power on qEEG in a brain region not affected on MRI was more likely to occur in subjects with more severe neurologic deficits. Conclusions: qEEG provides an objective measure of EEG asymmetry that correlates with clinical status and brain asymmetry seen on MRI. These findings support the conclusion that qEEG reflects the degree and extent of brain involvement and dysfunction in SWS. qEEG may potentially be a useful tool for early diagnosis and monitoring of disease progression in SWS. qEEG may prove useful, in severely affected individuals with SWS, for determining regions of brain dysfunction. [source]

The Ictal Bradycardia Syndrome: Localization and Lateralization

EPILEPSIA, Issue 4 2006
Jeffrey W. Britton
Summary:,Purpose: Previous studies have established the importance of the insular cortex and temporal lobe in cardiovascular autonomic modulation. Some investigators, based on the results of cortical stimulation response, functional imaging, EEG recordings of seizures, and lesional studies, have suggested that cardiac sympathetic and parasympathetic function may be lateralized, with sympathetic representation lateralized to the right insula, and parasympathetic, to the left. These studies have suggested that ictal bradycardia is most commonly a manifestation of activation of the left temporal and insular cortex. However, the evidence for this is inconsistent. We sought to assess critically the predictable value of ictal bradycardia for seizure localization and lateralization. Methods: In this study, we reviewed the localization of seizure activity in 13 consecutive patients with ictal bradycardia diagnosed during prolonged video-EEG monitoring at Mayo Clinic Rochester. The localization of electrographic seizure activity at seizure onset and bradycardia onset was identified in all patients. In addition, we performed a comprehensive review of the ictal bradycardia literature focusing on localization of seizure activity in ictal bradycardia cases. Results: All occurrences of ictal bradycardia in the 13 identified patients were associated with temporal lobe,onset seizures. However, no consistent lateralization of seizure activity was found at onset of seizure activity or at onset of bradycardia in this population. Seizure activity was bilateral at bradycardia onset in nine of 13 patients. The results from the literature review also showed that a predominance of patients had bilateral activity at bradycardia onset; however, more of the ictal bradycardia cases from the literature had left hemispheric localization of seizure onset. Conclusions: Ictal bradycardia most often occurs in association with bilateral hemispheric seizure activity and is not a consistent lateralizing sign in localizing seizure onset. Our data do not support the existence of a strictly unilateral parasympathetic cardiomotor representation in the left hemisphere, as has been suggested. [source]

A Magnetoencephalographic Study of Patients with Panayiotopoulos Syndrome

EPILEPSIA, Issue 7 2005
Osamu Kanazawa
Summary:,Purpose: Panayiotopoulos syndrome (PS) is a newly identified type of benign childhood epilepsy characterized by ictal vomiting and eye deviation. It is usually accompanied by occipital spike discharges; however, its classification as an early-onset benign childhood occipital epilepsy is controversial. To characterize this condition further, we examined the localization of equivalent current dipoles (ECDs) of spike discharges by magnetoencephalography (MEG) in patients with PS. Methods: We studied 13 patients with a mean age at time of examination of 5 years (range, 3,14 years). MEG was measured by using a whole-head 204-channel neuromagnetometer with simultaneous EEG recordings. The estimated locations of ECDs of each peak of the spike discharges were overlaid on magnetic resonance images of the brain. Results: Eleven (84.6%) patients showed clustered ECDs in the areas alongside the parietooccipital sulcus (eight of 13; 61.5%) and/or the calcarine sulcus (four of 13; 30.8%). Despite Fp-O synchronization of the spike discharges in the scalp EEG of five patients, no frontal locations of ECDs were found. All five (38.5%) boys with sylvian seizures, who also showed clustered ECDs in rolandic areas, had an earlier age at onset and higher seizure frequency than did other patients. ECD orientations were regular in all but one patient, who showed irregular and dispersed ECDs alongside bilateral calcarine sulci. Conclusions: Our results demonstrate localized cortical hyperexcitability in the areas alongside major cortical sulci in PS and indicate that PS is closely related to benign childhood epilepsy with centrotemporal spikes. [source]

Removing Eye-movement Artifacts from the EEG during the Intracarotid Amobarbital Procedure

EPILEPSIA, Issue 3 2005
Weidong Zhou
Summary:,Purpose: The EEG is often recorded during the intracarotid amobarbital procedure (IAP) to help in the assessment of the spatial extent and the duration of the effect of the drug. In scalp recordings, the EEG is always heavily contaminated with eye movement artifacts as the patient actively performs visual tasks. Methods: Independent component analysis (ICA) is a new technique for blind source separation. In this study, we separated the EEG data recorded during the IAP into independent components using ICA. The EEG signal was reconstructed by excluding the components related to eye movement and eye blinks. Results: EEGs from 10 IAP tests were analyzed. The experimental results indicate that ICA is very efficient at subtracting eye-movement artifacts, while retaining the EEG slow waves and making their interpretation easier. Conclusions: ICA appears to be a generally applicable and effective method for removing ocular artifacts from EEG recordings during IAP, although slow waves and ocular artifacts share similar frequency distributions. [source]

Consistent Localization of Interictal Epileptiform Activity on EEGs of Patients with Tuberous Sclerosis Complex

EPILEPSIA, Issue 3 2005
Floor E. Jansen
Summary:,Purpose: We addressed consistent localization of focal interictal epileptiform activity on EEGs of patients with tuberous sclerosis complex (TSC) and epilepsy. Methods: Twenty-one patients with TSC with a 10-year history of epilepsy and interictal epileptiform activity in three or more EEG recordings were included. None of the patients had undergone epilepsy surgery. Local maxima of interictal epileptiform activity were measured from 76 EEG traces and 33 EEG reports. Information about the patients' clinical course was extracted from their medical records. Magnetic resonance imaging (MRI) and neuropsychological examinations were performed. Statistical analysis was performed with the Mann,Whitney U test. Results: In eight patients, interictal epileptiform activity was consistently detected in one or two regions (group 1), and in 13 patients, epileptiform activity was detected in three or more regions (group 2). The number of foci increased throughout the disease course in both groups. Age at seizure onset and IQ were significantly higher in group 1. Complex partial seizures occurred more often in the patients of group 1. In 19 of the 21 patients, the most consistent epileptiform activity was localized in the frontotemporal region. Conclusions: Ninety percent of patients with TSC showed at least one region of consistent interictal epileptiform activity. Patients with one or two regions of epileptiform activity were older at seizure onset, often experienced complex partial seizures, and had mild or no mental deficits. These patients may be candidates for epilepsy surgery. [source]

fMRI of Brain Activation in a Genetic Rat Model of Absence Seizures

EPILEPSIA, Issue 6 2004
Jeffrey R. Tenney
Summary: Purpose: EEG-triggered functional magnetic resonance imaging (fMRI) was used to identify areas of brain activation during spontaneous spike-and-wave discharges (SWDs) in an epileptic rat strain under awake conditions. Methods: Spontaneous absence seizures from 10 WAG/Rij rats were imaged by using T2*-weighted echo planar imaging at 4.7 Tesla. fMRI of the blood-oxygenation-level,dependent (BOLD) signal was triggered based on EEG recordings during imaging. Images obtained during spontaneous SWDs were compared with baseline images. Results: Significant positive BOLD signal changes were apparent in several areas of the cortex and several important nuclei of the thalamus. In addition, no negative BOLD signal was found in any brain area. Conclusions: We have shown that EEG-triggered BOLD fMRI can be used to detect cortical and thalamic activation related to the spontaneous SWDs that characterize absence seizures in awake WAG/Rij rats. These results draw an anatomic correlation between areas in which increased BOLD signal is found and those in which SWDs have been recorded. In addition, no negative BOLD signal was found to be associated with these spontaneous SWDs. We also demonstrated the technical feasibility of using EEG-triggered fMRI in a genetic rat model of absence seizure. [source]

Polygenic Control of Idiopathic Generalized Epilepsy Phenotypes in the Genetic Absence Rats from Strasbourg (GAERS)

EPILEPSIA, Issue 4 2004
Gabrielle Rudolf
Summary: Purpose: Generalized nonconvulsive absence seizures are characterized by the occurrence of synchronous and bilateral spike-and-wave discharges (SWDs) on electroencephalographic recordings, concomitant with behavioral arrest. The GAERS (genetic absence rats from Strasbourg) strain, a well-characterized inbred model for idiopathic generalized epilepsy, spontaneously develops EEG paroxysms that resemble those of typical absence seizures. The purpose of this study was to investigate the genetic control of SWD variables by using a combination of genetic analyses and electrophysiological measurements in an experimental cross derived from GAERS and Brown Norway (BN) rats. Methods: SWD subphenotypes were quantified on EEG recordings performed at both 3 and 6 months in a cohort of 118 GAERS × BN F2 animals. A genome-wide scan of the F2 progenies was carried out with 146 microsatellite markers that were used to test each marker locus for evidence of genetic linkage to the SWD quantitative traits. Results: We identified three quantitative trait loci (QTLs) in chromosomes 4, 7, and 8 controlling specific SWD variables in the cross, including frequency, amplitude, and severity of SWDs. Age was a major factor influencing the detection of genetic linkage to the various components of the SWDs. Conclusions: The identification of these QTLs demonstrates the polygenic control of SWDs in the GAERS strain. Genetic linkages to specific SWD features underline the complex mechanisms contributing to SWD development in idiopathic generalized epilepsy. [source]

Corticothalamic Modulation during Absence Seizures in Rats: A Functional MRI Assessment

EPILEPSIA, Issue 9 2003
Jeffrey R. Tenney
Summary:,Purpose: Functional magnetic resonance imaging (fMRI) was used to identify areas of brain activation during absence seizures in an awake animal model. Methods: Blood-oxygenation-level,dependent (BOLD) fMRI in the brain was measured by using T2*-weighted echo planar imaging at 4.7 Tesla. BOLD imaging was performed before, during, and after absence seizure induction by using ,-butyrolactone (GBL; 200 mg/kg, intraperitoneal). Results: The corticothalamic circuitry, critical for spike,wave discharge (SWD) formation in absence seizure, showed robust BOLD signal changes after GBL administration, consistent with EEG recordings in the same animals. Predominantly positive BOLD changes occurred in the thalamus. Sensory and parietal cortices showed mixed positive and negative BOLD changes, whereas temporal and motor cortices showed only negative BOLD changes. Conclusions: With the BOLD fMRI technique, we demonstrated signal changes in brain areas that have been shown, with electrophysiology experiments, to be important for generating and maintaining the SWDs that characterize absence seizures. These results corroborate previous findings from lesion and electrophysiological experiments and show the technical feasibility of noninvasively imaging absence seizures in fully conscious rodents. [source]

Seizure Suppression by Adenosine A1 Receptor Activation in a Mouse Model of Pharmacoresistant Epilepsy

EPILEPSIA, Issue 7 2003
Nicolette Gouder
Summary: Purpose: Because of the high incidence of pharmacoresistance in the treatment of epilepsy (20,30%), alternative treatment strategies are needed. Recently a proof-of-principle for a new therapeutic approach was established by the intraventricular delivery of adenosine released from implants of engineered cells. Adenosine-releasing implants were found to be effective in seizure suppression in a rat model of temporal lobe epilepsy. In the present study, activation of the adenosine system was applied as a possible treatment for pharmacoresistant epilepsy. Methods: A mouse model for drug-resistant mesial temporal lobe epilepsy was used, in which recurrent spontaneous seizure activity was induced by a single intrahippocampal injection of kainic acid (KA; 200 ng in 50 nl). Results: After injection of the selective adenosine A1 -receptor agonist, 2-chloro- N6 -cyclopentyladenosine (CCPA; either 1.5 or 3 mg/kg, i.p.), epileptic discharges determined in EEG recordings were completely suppressed for a period of ,3.5 h after the injections. Seizure suppression was maintained when 8-sulfophenyltheophylline (8-SPT), a non,brain-permeable adenosine-receptor antagonist, was coinjected systemically with CCPA. In contrast, systemic injection of carbamazepine or vehicle alone did not alter the seizure pattern. Conclusions: This study demonstrates that activation of central adenosine A1 receptors leads to the suppression of seizure activity in a mouse model of drug-resistant epilepsy. We conclude that the local delivery of adenosine into the brain is likely to be effective in the control of intractable seizures. [source]

Lateralising Value of Neuropsychological Protocols for Presurgical Assessment of Temporal Lobe Epilepsy

EPILEPSIA, Issue 3 2003
Nozomi Akanuma
Summary: ,Purpose: To estimate the value of neuropsychological measurements in determining the side of seizure onset for presurgical assessment in patients with temporal lobe epilepsy. The lateralising value of neuropsychological protocols was evaluated for all patients and in subpopulations depending on surgical outcome with regard to seizure control, speech dominance, neuropathology, and need for intracranial EEG recordings. Methods: A battery of neuropsychological procedures was carried out preoperatively in 125 patients who underwent left (n = 66) or right (n = 59) temporal lobectomies. Binary logistic regression analysis was performed to find sets of variables that allowed the best prediction of the side of seizure onset (assumed to be the operated-on side). Results: Combinations of noninvasive neuropsychological tests and Wada subscores showed the highest lateralising values: 80.8% for all patients, 79.4% in seizure-free patients, 86.0% in patients not rendered seizure free, 85.7% in left speech patients, 77.8% in non,left speech patients, 89.3% in patients with mesial temporal sclerosis (MTS), 78.1% in non-MTS patients, 80.3% in patients who underwent intracranial EEG recordings, and 77.3% in those who did not. Conclusions: The lateralising value (80-90%) of neuropsychological protocols appears similar to that of other tests widely accepted for lateralisation (ictal and interictal scalp EEG and neuroimaging). Attention should be paid to neuropsychological results, particularly from the Wada test, during presurgical assessment of temporal lobe epilepsy, as they can provide strong support for findings from other lateralising tests, particularly in patients with presumed MTS or in left-speech patients. [source]