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At least 937 records · Page 52Linked to original sources
PubMed1999

Electrical stimulation of the contralateral mesial temporal structure induces an ipsilateral seizure pattern in mesial temporal lobe epilepsy.

PURPOSE: We examined the mode of seizure development induced by electrical stimulation in patients with mesial temporal lobe epilepsy. METHODS: Of 25 patients undergoing intracranial EEG evaluation and electrical stimulation ipsilateral to the presumed site of habitual seizure origin, 17 patients had additional stimulation studies on the contralateral temporal lobe. RESULTS: Fourteen of the 25 patients had seizures induced with ipsilateral stimulation, and two of the 17 patients had seizures with contralateral stimulation. Seizures induced by ipsilateral stimulation started in the ipsilateral temporal lobe, whereas those induced by contralateral stimulation originated from the ipsilateral temporal lobe structure and were identical to the habitual seizures. CONCLUSIONS: Electrical stimulation of the temporal lobe structure opposite the site of habitual seizure origin is said to induce a seizure rarely. However, according to our preliminary results, if contralateral stimulation elicits a habitual seizure in the ipsilateral temporal lobe, it might be considered additional confirmatory evidence of seizure lateralization.

Adult↗
PubMed1999

Confirmation of two magnetoencephalographic epileptic foci by invasive monitoring from subdural electrodes in an adolescent with right frontocentral epilepsy.

PURPOSE: To report our evaluation of interictal two epileptic spike fields on magnetoencephalography (MEG) by using invasive intracranial monitoring in a patient without lesion on magnetic resonance imaging (MRI). METHODS: A 15-year-old left-handed boy with a 9-year history of refractory simple partial seizures, secondarily generalized, and a normal MRI, was studied with MEG to define magnetic spike sources, followed by invasive intracranial monitoring with subdural electrodes to delineate the epileptogenic zone and eloquent function pursuant to focal cortical excision. RESULTS: MEG demonstrated two spike foci on the right middle frontal and inferior rolandic areas adjacent to the sensory area. Ictal recordings during prolonged invasive monitoring from subdural electrodes revealed two epileptogenic zones in the same locations as those defined by MEG. Focal cortical excision was performed of each epileptogenic zone. The patient has been seizure free for 24 months without neurologic deficit. CONCLUSIONS: Magnetic source imaging is a valuable adjunct in the planning of subdural grid placement in epilepsy surgery, particularly in patients in whom conventional imaging fails to reveal a lesion.

Adolescent↗
PubMed2005

Origin and propagation of epileptic spasms delineated on electrocorticography.

PURPOSE: Ictal electrographic changes were analyzed on intracranial electrocorticography (ECoG) in children with medically refractory epileptic spasms to assess the dynamic changes of ictal discharges associated with spasms and their relation to interictal epileptiform activity and neuroimaging findings. METHODS: We studied a consecutive series of 15 children (age 0.4 to 13 years; nine girls) with clusters of epileptic spasms recorded on prolonged intracranial subdural ECoG recordings, which were being performed for subsequent cortical resection, and in total, 62 spasms were analyzed by using quantitative methods. RESULTS: Spasms were associated with either a "leading" spike followed by fast-wave bursts (type I: 42 events analyzed quantitatively) or fast-wave bursts without a "leading" spike (type II: 20 events analyzed quantitatively). Twenty-three of the 42 type I spasms but none of the 20 type II spasms were preceded by a focal seizure. A "leading" spike had a focal origin in all 42 type I spasms and involved the pre- or postcentral gyrus within 0.1 s in 37 of these spasms. A leading spike was associated with interictal spike activity >1/min in 40 of 42 type I spasms and originated within 2 cm from a positron emission tomography glucose hypometabolic region in all but two type I spasms. Failure to resect the cortex showing a leading spike was associated with poor surgical outcome (p = 0.01; Fisher's exact probability test). Fast-wave bursts associated with spasms involved neocortical regions extensively at least in two lobes within 1.28 s in all 62 spasms and involved the pre- or postcentral gyrus in 53 of 62 spasms. CONCLUSIONS: Epileptic spasms may be triggered by a focal neocortical impulse in a subset of patients, and a leading spike, if present, might be used as a marker of the trigger zone for epileptic spasms. Rapidly emerging widespread fast-wave bursts might explain the clinical semiology of epileptic spasms.

Brain Mapping↗
PubMed2006

Efficacy of dexamathasone on cerebral swelling and seizures during subdural grid EEG recording in children.

PURPOSE: To evaluate the impact of steroid treatment on cerebral swelling and seizures during subdural grid EEG (SGEEG) monitoring. METHODS: We reviewed data from 37 pediatric patients with intractable epilepsy who underwent SGEEG monitoring and divided the patients into those who received dexamethasone and those who did not. We then correlated administration of steroids to incidence of cerebral swelling on computed tomography (CT) scans and to frequency of seizures during SGEEG. RESULTS: Twenty-three patients received dexamethasone prophylactically every 6 hours (dosage range, 1-7.5 mg; mean, 3.2 mg) from the first day of SGEEG placement (group A); 14 patients received no dexamethasone (group B). Eight (21.6%) of 37 patients experienced cerebral swelling on CT: two (9%) were in group A, and six (42.9%) were in group B (p < 0.05). SGEEG monitoring time for recording habitual seizures that localized cortical areas for surgical excision was longer in group A (1-6 days; mean, 3.0) than it was in group B (1-3 days; mean, 2.2), (p < 0.05). Habitual seizures were recorded in 36 patients. One group A patient experienced obtundation due to cerebral swelling, and monitoring in this patient was discontinued. CONCLUSIONS: The prophylactic administration of steroids to pediatric patients during SGEEG monitoring is efficacious for reducing cerebral swelling. Although it decreases the frequency of habitual seizures and increases seizure-monitoring time, dexamethasone reduces the risk of complications from cerebral swelling during the SGEEG procedure.

Adolescent↗
PubMed2006

Topographic movie of ictal high-frequency oscillations on the brain surface using subdural EEG in neocortical epilepsy.

PURPOSE: To understand the rapid dynamic changes of ictal intracranial high-frequency oscillations (HFOs) in neocortical epilepsy. METHODS: We integrated multiple band frequency analysis and brain-surface topographic maps of HFOs from ictal subdural EEG (SDEEG) recordings. We used SDEEG to record partial seizures consisting of right-arm jerks with secondary generalization in a 17-year-old right-handed girl. We selected 20-s EEG sections that included preclinical seizure recordings. We averaged the HFO power between 60 and 120 Hz for 25 selected electrodes, made topographic maps from these averaged powers, and superimposed the maps on the brain-surface image. We filmed consecutive HFO maps at a 10-ms frame rate. RESULTS: Before clinical seizure onset, high-power HFOs emerged at the superior portion of the left precentral gyrus, then appeared in the middle of the left postcentral gyrus, and subsequently reverberated between both regions as well as the posterior portion of the left postcentral gyrus. Right-arm extension and facial grimacing started as the HFO power decreased. As generalized tonic-clonic seizures evolved, HFO power increased but remained within the central region. CONCLUSIONS: Topographic movies of intracranial HFOs on the brain surface allow visualization of the dynamic ictal changes in neocortical epilepsy.

Adolescent↗
PubMed2006

Management of cerebral spinal fluid leak complicating spinal cord stimulator implantation.

Accidental puncture of the dura mater with resultant leakage of cerebral spinal fluid (CSF) and development of postdural puncture headache (PDPH) is a known potential complication of percutaneous placement of spinal cord stimulator (SCS) leads. However, the implications and management strategies for this complication have not been thoroughly reported. We report two cases of SCS lead placement complicated by CSF leak and PDPH.

Adolescent↗
PubMed2001

Extensive subdural mass.

An unusual case of a 62-year-old man with focal seizures, tinnitus, and progressive left hemiparesis due to an extensive subdural plasma cell granuloma is presented. Five-year clinical and radiologic follow-up demonstrating the chronic yet progressive nature of this granuloma is presented. This is the first report of focal calcification seen in an intracranial plasma cell granuloma. The imaging, neuropathologic, and clinical characteristics of this rare lesion are reviewed.

Brain Diseases↗
PubMed1993

Outcome of resective surgery for intractable partial epilepsy guided by subdural electrode arrays.

The aim of this paper was to evaluate the outcome and the factors predictive for a good prognosis of resective surgery for intractable partial epilepsy guided by subdural electrode arrays (SEA's) and operative electrocorticography. Sixty-four patients, aged 8-52 years, were evaluated with chronic SEAs in order to record interictal and ictal activity and delineate speech and motor areas by functionally mapping. Resection were individualized to each patient's SEA recorded electrocorticogram and operative electrocorticogram and functional mapping results (tailored resection). The follow-up time was a minimum of one year. Good seizure outcome was defined as seizure free from complex partial and secondary generalized seizures. After one year 70% of the patients with a temporal ictal focus was seizure free compared to 55% of the patients with an extra-temporal focus. Complete resection of interictal or ictal fields as mapped with SEAs, gave better prognosis than partial resection. Patients with no postresection spikes had a better prognosis than patients with residual postresection spikes evaluated with operative electrocorticography. Sex, age, duration of epilepsy prior to surgery, extent of temporal lobe resection and structural abnormalities determined by MRI were not associated with a favorable seizure outcome after surgery. We conclude that complete resection of the interictal and ictal field mapped with SEA's and absence of postresection spikes on operative electrocorticography are associated with an excellent seizure outcome.

Adolescent↗
PubMed1994

Subdural electrodes.

Physical aspects favour subdural registrations: as the solid angle under which a source is seen from a nearby electrode, the potential is large; there is no distortion by high impedence between source and electrode, nor by perpendicular short circuits; the frequency response is quasi-linear. Technical aspects and implantation strategy are outlined. Interictal and ictal ECoG patterns of diagnostical relevance and activation procedures are discussed. Advantages of subdural electrodes are: They provide detailed information on the epileptogenic zone, data on prognosis, are free of artefacts, allow electrical stimulation to determine eloquent cortex areas; by mathematical analysis methods the localizing power is increased. Disadvantages are: closed fields can be missed (recordable only by depth electrodes), in comparison to EEG, costs are considerably higher. Risks are practically absent with strip electrodes. In about half of the investigated patients, subdural electrodes were necessary to minimize the area of resection on a rational basis.

Brain↗
PubMed1997

Cerebral blood flow changes associated with fetal intracranial hemorrhages.

UNLABELLED: BACKGROUND AND MATERIAL: In order to evaluate cerebral blood flow changes associated with fetal intracranial hemorrhages, ultrasound and MRI examinations were carried out in four pregnancies with this complication. RESULTS: Increased resistance indices of the blood flow profile of the middle cerebral artery were detected in three of the fetuses, two of them presenting retrograde diastolic flow. Flow became normalized in one case within four weeks, changing on the contralateral side to an increased diastolic flow pattern. CONCLUSION: Increased intracranial pressure can cause these flow changes, but cerebral blood flow autoregulation need not be completely ruined in this complication.

Cerebral Hemorrhage↗
PubMed1975

Postirradiation syndrome and eeg findings in children with acute lymphoblastic leukaemia.

Out of 12 children with acute lymphoblastic leukaemia treated with craniospinal irradiation during primary haematologic remission, 8 developed a postirradiation syndrome characterized by fever and tiredness. The symptoms lasted 1-2 weeks and subsided spontaneously. Longitudinal EEG studies revealed no acute disturbances during the irradiation therapy but in all cases studied, moderate to severe diffuse general slowing developed during the postirradiation syndrome. Complete normalization of the EEG occurred in all children at follow-up. It is concluded that the described EEG abnormalities constitute an integral part of the postirradiation syndrome.

Adolescent↗
PubMed2001

Extraction and analysis of early ictal activity in subdural electroencephalogram.

Subdural electroencephalograms (SEEGs) are of great value in localizing primary epileptogenic regions in patients undergoing evaluation for focal resective epilepsy surgery. The data segments which contain a transition from interictal to ictal activity carry the most critical diagnostic information. Computer signal extraction within this transition period represents a challenging signal processing problem. In this work a two-step method is presented to extract early ictal activity. In the first step we employ a nonlinear signal decomposition technique in the wavelet domain to separate SEEG data into ictal and background components. In the second step we use time-frequency analysis and a novel integration algorithm to extract the desired information. Our experiments on clinically recorded data indicate that this method is highly effective allowing us to reveal important hidden features in the data which could not otherwise be observable.

Adult↗
PubMed1984

Cefuroxime treatment of bacterial meningitis in infants and children.

Recently, ampicillin- and chloramphenicol-resistant strains of Haemophilus influenzae type b and multiply-resistant Salmonella strains have appeared in some areas of the world. Therefore, alternative drug therapy for infections caused by these organisms is being sought. We used cefuroxime to successfully treat five children with H. influenzae type b meningitis and two children with Salmonella meningitis. Four H. influenzae type b isolates and one Salmonella isolate were resistant to ampicillin, chloramphenicol, and cotrimoxazole. Each of the patients received 200 to 250 mg of cefuroxime per kg per day in four divided doses for 14 to 21 days. The concentrations of cefuroxime in cerebrospinal fluid at 2 h after intravenous 50-mg/kg doses were 6.4 +/- 1.7 (mean +/- standard deviation) and 3.6 +/- 2.2 micrograms/ml on days 2 and 14 of treatment, respectively. The level of drug in cerebrospinal fluid was 1.34 +/- 1.3 micrograms/ml in children without meningitis. The mean cefuroxime concentration in subdural fluid samples from each of three patients was 12.6, 15, and 25.2 micrograms/ml. Cefuroxime is recommended as an alternative drug for the treatment of H. influenzae type b meningitis, but additional information is necessary before cefuroxime can be recommended for therapy of Salmonella meningitis.

Body Fluids↗
PubMed1976

Brain abscess and subdural empyema. Factors influencing mortality and results of various surgical techniques.

The authors review the results of various surgical techniques in relation to mortality and morbidity in 100 consecutive cases of brain abscess and subdural empyema. The mortality rate is the same with total excision and fractional drainage of brain abscesses, although in acute and subacute cases slight differences between both techniques are seen. In terms of morbidity, fractional drainage appears to be more favourable than total excision. The authors believe that factors other than surgical procedure influence mortality in cases of brain abscess and subdural empyema. These factors are defined in detail.

Acute Disease↗
PubMed1981

The linearity of the volume/pressure response during intracranial pressure "reserve" testing.

The intracranial pressure "reserve" test seems to be the most reliable method of determining when the brain's natural mechanisms for pressure compensation for added intracranial volume have been compromised or exhausted. The test employs a timed sequence of intracranial fluid injections, but as a safety precaution injections are discontinued if intracranial pressure remains elevated more than 10 Torr over baseline. In this case, a linear extrapolation is then calculated to determine the elevation which might have been achieved by a full series of injections. However, this linear extrapolation has been criticised on the expectation that an exponential response should be expected. A series of experimental observations in dogs and baboons and a review of clinical records in humans have been made to determine the observed slope of increase following aliquot injection during performance of the intracranial pressure reserve test. In these species the observed response was actually linear in shape rather than exponential. This held true even for different initial baseline values and with different volumes of "lesion" balloon inflations in experimental animals. A theoretic explanation is proposed.

Animals↗