SEARCH · PubMed Health

Results for “ELECTROENCEPHALOGRAPHY”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10Linked to original sources

PubMed2001

Comparative utility of technetium-99m hexamethylpropylenamine oxime single photon emission computed tomography (SPECT) with anatomic neuroimaging and electroencephalography (EEG) in childhood intractable epilepsy.

Intractable epilepsies pose a therapeutic challenge. Precise localization of the epileptic focus is imperative before planning surgical intervention. Functional imaging is an important component of presurgical work-up. Positron emission tomography is unavailable in developing countries; hence, the need to evaluate the available imaging modality, single photon emission computed tomography (SPECT), was felt. We investigated 61 children with intractable epilepsy, identified by predefined criteria, by performing electroencephalography (EEG), magnetic resonance imaging (MRI), computed tomography (CT), and ictal and interictal SPECT. The localizing value of ictal and interictal SPECT imaging for epileptic foci was correlated with clinical, electrophysiologic, and anatomic neuroimaging data. An ictal SPECT was obtained in 9, and interictal SPECT was performed in all (61). Ictal SPECT was localizing in 8 of 9 (88.8%). Interictal SPECT was localizing in a significantly higher proportion of patients (47.54%) than either the scalp EEG (16.39%) (P = .0003) or CT scan (21.56%) (P = .0046). Our data demonstrated that interictal and ictal SPECT identified more focal changes in children with intractable epilepsy than interictal EEG, CT, and probably MRI. The definitive proof of the SPECT-based findings being epileptogenic foci awaits correlation with intraoperative monitoring and postoperative follow-up.

Adolescent↗

PubMed2001

Utility of electroencephalography in the pediatric emergency department.

To assess the role of electroencephalography (EEG) in the pediatric emergency department, we reviewed the records of all patients having an EEG in the pediatric emergency department of our hospital between 1995 and 1997. EEG findings, clinical presentations, and follow-up data were analyzed, and patients were distributed into three groups according to clinical presentation: group 1 included patients with new-onset seizures, group 2 included patients with known epilepsy presenting with worsening seizures and altered mentation, and group 3 comprised patients with acute confusional states. Overall, 56 patients with 57 EEGs were included. In group 1 (n = 36), 20 (55.6%) had an abnormal EEG. The risk of recurrence was much higher in children with abnormal EEGs (80% vs. 31%) (P < .01). In retrospect, among all of the patients receiving the diagnosis of epilepsy, 76% had an abnormal emergency department EEG. Four in group 2 (n = 14) and one in group 3 (n = 7) were proven to have nonconvulsive status epilepticus and were treated accordingly. No patients in group 1 had nonconvulsive status epilepticus. Ongoing seizures were promptly excluded in the remainder. The EEG directly contributed to the diagnosis in 84% of all referrals in the pediatric emergency department, either being abnormal and leading to a diagnosis of a seizure disorder or confirming low suspicion for seizures. Thus, a prompt EEG should be considered in children with new-onset seizures and unexplained altered consciousness.

Child↗

PubMed2002

Normally developed infant with a suppression burst pattern on electroencephalography in the neonatal period.

The background activity on neonatal electroencephalography (EEG) is a good prognostic indicator. An EEG suppression burst pattern usually indicates severe brain dysfunction and has been considered to be associated with a serious neurodevelopmental outcome. We report here a 2-year-old girl who developed generalized convulsions without any perinatal brain insult at 3 days of age. At that time, her EEG constantly showed a suppression burst pattern, and her prognosis was considered to be poor. However, her seizures were well controlled with the oral administration of carbamazepine, and the suppression burst pattern on EEG disappeared at 27 days of age. Unexpectedly, she developed normally for the following 2 years. Although children with normal development, despite the appearance of suppression burst, are extremely rare, and the reason why this patient showed a favorable outcome remains unknown, the clinical course of this patient proved that an EEG suppression burst pattern is not always associated with a poor prognosis.

Anticonvulsants↗

PubMed2003

Utility of electroencephalography in the evaluation of common neurologic conditions in children.

The objective of this study was to assess the utility of electroencephalography (EEG) in the evaluation of common neurologic conditions in children. The EEG recordings of 534 consecutive children (aged < 20 years) were prospectively read by a certified pediatric neurologist. Common diagnostic indications included the following: clinical seizures (33.8%), definite epilepsy (31.2%), attention-deficit hyperactivity disorder (ADHD) (9.1%), headache (8%), syncope (3.5%), learning disabilities (2%), tic disorders (1.4%), and sleep disorders (1.1%). Overall, 63.8% of EEG records were normal, slowing background activity was noted in 6.1%, ADHD was noted in 35.3% (definite epilepsy), and epileptiform activity was noted in 37.1% of the cases of definite epilepsy and 13.2% of the clinically suspected cases. Epileptiform activity was rarely found in the patients without epilepsy. All EEG records of children with syncope (n = 19) and headache (n = 43) were normal. These findings indicate that although EEG plays an important diagnostic role in epilepsy, interictal EEG is being overused during evaluation of various neurologic disorders in children, and a normal EEG is highly predictable in children with nonepileptic conditions.

Adolescent↗

PubMed2005

Neurophysiologic findings of neuronal migration disorders: intrinsic epileptogenicity of focal cortical dysplasia on electroencephalography, electrocorticography, and magnetoencephalography.

We define specific neurophysiologic characteristics for focal cortical dysplasia, a neuronal migration disorder. We reviewed data from published reports and our patients with focal cortical dysplasia. Our patients underwent preoperative scalp video-electroencephalography (EEG), magnetic resonance imaging (MRI), magnetoencephalography, and intraoperative or extraoperative electrocorticography monitoring. Scalp EEG showed trains of rhythmic epileptiform spike or sharp waves. Positive spikes correlated with early seizure onset, MRI lesion around the rolandic fissure, hemiparesis, and a less favorable outcome. Interictal electrocorticography showed continuous epileptogenic discharges: repetitive electrographic seizures and bursting discharges or continuous or quasicontinuous rhythmic spiking. Ictal electrocorticography showed paroxysmal fast and/or repetitive spiking. Magnetoencephalography showed clustered spike sources within and extending from the lesion. Cortical stimulation gave more frequent, lower-threshold afterdischarges and higher-threshold primary motor function. Focal cortical dysplasias are highly and intrinsically epileptogenic. For surgical seizure control, EEG, electrocorticography, and magnetoencephalography must delineate the intrinsic epileptogenic zone within and extending from the focal cortical dysplasia identified by MRI.

Brain Mapping↗

PubMed1999

Clinical neurophysiology using electroencephalography in geriatric psychiatry: neurobiologic implications and clinical utility.

Electroencephalography (EEG) offers a unique contribution to the armamentarium of imaging technologies used in the evaluation of brain function. The primary clinical application of EEG is in the diagnosis of delirium, dementia, and epilepsy, which are frequently encountered in the practice of geropsychiatry. This review summarizes the principles behind generation of the EEG signal, its strengths and limitations as a technology, clinical indications for performing an EEG, the principles underlying quantitative EEG (QEEG), and how QEEG is allowing us to probe brain function and connectivity in new ways.

Aged↗

PubMed1996

Accuracy of 133-xenon regional cerebral blood flow and quantitative electroencephalography in systemic lupus erythematosus.

OBJECTIVE: Comparative assessment of sensitivity and specificity of regional Cerebral Blood Flow (rCBF) by 133-Xenon inhalation and quantitative Electroencephalography (qEEG) in patients with Neuropsychiatric Systemic Lupus Erythematosus (NP-SLE). METHODS: Sixty-two combined rCBF and qEEG examinations were performed in fifty-two SLE patients. Group A: 27 SLE patients without NP-SLE; group B: 17 patients with florid (within 1 month) NP-SLE; group C: 12 patients previous NP-SLE examined in the remission phase (four patients of which already considered in group B). The study also included data deriving from two sets of examinations in ten patients who were observed twice, in different phases of the clinical course of NP-SLE. RESULTS: In comparison to healthy controls, rCBF lower (p < .001) in group B only, whereas qEEG showed similar increases of both delta and theta relative powers together with a reduction of alpha relative power in groups A-C. As compared to group A, sensitivity and specificity in detecting cerebral abnormalities in group B were 76% and 78% for rCBF, and 59% and 44% for qEEG, respectively. In the ten patients examined twice, rCBF was consistent with clinical course in 90% of cases and qEEG in 60%. CONCLUSION: Total accuracy in detecting cerebral functional abnormalities during florid NP-SLE is better by rCBF than by qEEG. rCBF and, in selected cases, qEEG examinations are reliable markers of NP-SLE.

Adolescent↗

PubMed2000

Data mining and electroencephalography.

An overview of data mining (DM) and its application to the analysis of DM and electroencephalography (EEG) is given by: (i) presenting a working definition of DM, (ii) motivating why EEG analysis is a challenging field of application for DM technology and (iii) by reviewing exemplary work on DM applied to EEG analysis. The current status of work on DM and EEG is discussed and some general conclusions are drawn.

Algorithms↗

PubMed2006

Electroencephalography hyperventilation and stroke in children with sickle cell disease.

A recent study and report in which hyperventilation was used during electroencephalography (EEG) in 6 children with sickle cell disease (SCD) and seizures, without serious complication, prompted a cautionary response regarding the potential risks attending the practice of EEG hyperventilation in SCD patients. Earlier reports of neurological impairment and stroke precipitated by the routine use of hyperventilation in children with SCD are reviewed, the mechanism and management of vascular infarction following hyperventilation are discussed, and readers are reminded of the AEEGS guidelines and contraindications to routine hyperventilation, which include SCD and trait and cerebrovascular disorders. The frequent nonobservance of these guideline recommendations among neurologists, and the need to more widely inform practitioners of the risks of hyperventilation in SCD are discussed.

Adolescent↗

PubMed1989

Electroencephalography in the early diagnosis of HIV-related subacute encephalitis: analysis of 185 patients.

Of subjects with asymptomatic HIV infection or Lymphoadenopathy Syndrome, 185 were studied by means of electroencephalography coupled with computerized spectral analysis and mapping (EEG-CSA). Abnormal EEGs were found in 30 of 118 (25.4%) patients with asymptomatic infection (CDC Group II) and in 20 of 67 (29.9%) patients with Lymphoadenopathy Syndrome (CDC Group III). The most common EEG abnormalities were represented by theta slowing on the frontal and fronto-temporal lobes and, in some cases, by delta slowing and paroxysmal sharp activity on the forebrain. Among 50 patients with abnormal EEGs, 16 showed some abnormalities on neuropsychological testing, whereas mild signs of cerebral atrophy were evident on CT scan in only 12 patients. These findings suggest that EEG-CSA could be a useful and sensitive method in the early detection and monitoring of HIV-related subacute encephalitis.

Acquired Immunodeficiency Syndrome↗

PubMed1996

Present state of development of neo-electroencephalography.

Neo-electroencephalography (neo-EEG) is a new technique for recording and analyzing brain activity. Mathematical and computerized reconstitution yields a monopolar-like montage. Given the polymorphism of the brain's electrical activity, the computer detects the correct monopolar-like montage for each activity in steps of 0.25 Hz. Conventional EEG detects the difference in potentials between two electrodes. Through the use of monopolar-like montages neo-EEG analysis reveals the amplitude and phase that actually underlie each electrode. The report describes with precision the features of the recording extracts that have been chosen for the analysis, i.e., the number of dominant frequencies, the frequency to the nearest 0.25 Hz and the frequency spectrum for each dominant frequency, then the amplitude to the nearest 0.1 microv and phase shift to the nearest 0.001 sec at each electrode. Some examples of comparisons between neo-EEG and conventional EEG findings are shown and demonstrate the advantages of neo-EEG in detection and differentiation of organic and functional pathologies.

Alpha Rhythm↗

PubMed1983

Clinical evaluation of a depth electroencephalography electrode.

Stereo depth electroencephalography (EEG) is of proven benefit in lateralizing and localizing seizure origin in select cases of epilepsy. There are potential hazards and technical considerations inherent with depth EEG, however, that have limited the general applicability of this technique. A new depth EEG electrode with materials and design features that facilitate safe insertion and artifact-free recording has been developed. The design features and technique for inserting the electrode are described. The electrode was evaluated during 2600 hours of implantation and recording in seven patients. With the use of stereotactic techniques, the electrode could be positioned accurately within precise anatomical landmarks such as the amygdaloid nucleus and the hippocampus. After insertion, no hemorrhage or edema was detected along the electrode tracts by third generation computed tomographic scanning. There was no evidence of pyrogenicity or infection. Electrode migration was not observed. A large electrical field could be sampled because of the relatively large surface of the cylindrical depth electrode contacts.

Electrodes, Implanted↗

PubMed1989

[Baseline study of sleep electroencephalography--daily variation and individual variation].

The aims of the present study were to observe the daily habituation to night sleep in a laboratory environment and to make clear the daily and individual sleep variations by using polygraph parameters, including electroencephalography (EEG). Sleep EEG records were obtained from a subject who slept ten successive nights, and from six subjects who each slept one night in the laboratory. The parameters used were as follows: sleep stage %, sleep latency (SL), REM latency (RL), number of stage shifts, subjective sleep, integral EMG, and slope (a) and intersect (b) of a regression equation used to estimate the sleep depth against sleep time. Stage WAKE and SL, slope (a), intersect (b) and the mean depth of sleep were found to become stable from the fifth night. Stage MT, the number of stage shifts, and integral EMG increased significantly from the fifth night and later, showing p less than 0.01, p less than 0.01, and p less than 0.05, respectively. Judging from these findings, the sleep habituation of the subject in the laboratory was completed within the first four nights. Coefficients of variation of sleep stage 2 and stage REM of the ten-nights' EEG were the lowest among all the sleep parameters examined. Almost all the parameters of day-to-day sleep of the subject who slept for ten successive nights in the laboratory showed smaller variations than those of the other six subjects. It may be concluded that the mist effect on sleep could be assessed more precisely by using an individual repeatedly than by using a group of subjects.

Adult↗

PubMed1998

[Electroencephalography and prognosis in stroke patients].

Electroencephalography (EEG) and its relationship to prognosis were studied in 105 patients with cerebrovascular disease in the acute to subacute stages. Twenty cases had normal EEG, and most of them recovered well. Fifty-five cases had mildly to moderately abnormal EEG with focal asymmetric or slow waves in the unilateral hemisphere. Among them, 41 cases (75%) recovered to the extent of being capable of independent walking, 38 cases (69%) recovered sufficiently to engage in independent activities of daily livings (ADL) and 42 cases (76%) returned home. On the other hand 30 cases who had severely abnormal EEG with diffuse slow waves in the unilateral or bilateral hemispheres showed a poor prognosis. Among them, 18 cases (60%) were confined to bed, 20 cases (69%) remained in totally dependent ADL, and 4 cases (13%) died. Thus, EEG is shown to reflect well functional recovery in stroke patients.

Activities of Daily Living↗

PubMed2006

Electroencephalography (EEG) spectral edge frequency for assessing the sedative effect of acupuncture in dogs.

Electroencephalography (EEG) is an effective method for the evaluation of sedation or anesthesia. The purpose of this study was to examine the sedative effect of acupuncture by electroencephalographic spectral edge frequency (SEF) in Miniature Schnauzer dogs (4.2-6.1 kg, 1-2 years old). The acupuncture points "GV20 and Yintang" were applied for 20 min. Sedation level was assessed before, during, and after acupuncture by spectral edge frequency 95 values and the Ramsay sedation score. The spectral edge frequency 95 values were significantly reduced during acupuncture on GV20 or Yintang point and returned to the baseline values after acupuncture releasing. The Ramsay sedation score (RSS) also showed the acceptable sedation level during acupuncture. It was concluded that an acupuncture application at GV20 or Yintang point used in the present study would be a valuable method to induce the sedation in dogs.

Acupuncture↗

PubMed1997

[Effect of boundary element discretization on forward calculation and the inverse problem in electroencephalography and magnetoencephalography].

Modelling in magnetoencephalography (MEG) and electroencephalography (EEG) is increasingly based on the boundary element method (BEM). We quantify the influence of boundary element discretization on the neuromagnetic and neuroelectric forward and inverse problem for different dipole depths, brain regions and the quasispherical correction. In particular we derive standards for the general use of BEM models in MEG/EEG source localization. For this purpose simulation with single current dipoles, and source reconstructions from somatosensory evoked potentials and magnetic fields were employed. It was found that both local and global discretization influence source reconstruction. Only at a minimum triangle side length of 10 mm was it possible to achieve stable results for MEG and EEG. In order to obtain acceptable errors within the stable region, the ratio of dipole depth to triangle side length must not be less than 0.5. The results obtained from a comparison of the different brain regions indicate that the similarity to spherical geometry might well have an influence on the estimated dipole location, but not so much on its strength. Source reconstruction employing quasispherical correction was found to be the most stable, in particular in the case of coarse BEM discretization.

Adult↗

PubMed1987

Sleep-electroencephalography and the secretion of cortisol and growth hormone in normal controls.

Sleep-electroencephalography, and the nocturnal secretion of cortisol and GH were investigated simultaneously in a sample of 25 male normal controls (27.1 +/- 1.3 years) in order further to examine interaction between sleep structure and concurrent endocrine activity. Slow wave sleep activity was increased during the first part of the night, whereas cortisol concentration was low and GH output reached maximal levels. The second half of the night was characterized by a relative preponderance of REM-sleep, low GH-concentration, and an increase in cortisol. However, no distinct reciprocal interaction between cortisol and GH concentration was noted. In all subjects, a pronounced GH surge between 22.00 and 02.00 h was recorded which occurred independently of the presence of slow wave sleep. Six out of the 25 subjects showed nocturnal GH increases even before sleep onset. These data indicate that somatotropic cell activity during night is less dependent upon the sleeping state or specific conventially defined sleep stages than originally reported.

Adult↗

PubMed1999

Assessment of neonatal encephalopathy by amplitude-integrated electroencephalography.

OBJECTIVE: To define normal and abnormal patterns, test interobserver variability, and the prognostic accuracy of amplitude-integrated electroencephalography (aEEG) soon after the onset of neonatal encephalopathy. METHODS: Consecutive cases of neonatal encephalopathy (n = 56; gestation median, 40; range, 35-42 weeks) and healthy infants (n = 14; gestation median, 40; range, 39-40 weeks) were studied. aEEG was recorded using a cerebral function monitor, at median, 0, range, 0-21 days of age. Of the infants, 24 of the 56 with encephalopathy and all of the normal infants were studied within 12 hours of birth (median, 5; range, 3-12 hours). Forty infants were suspected of having suffered birth asphyxia. Criteria for normal and abnormal patterns were defined and the interobserver variability of these classifications determined. Results were compared with neurodevelopmental outcome assessed at 18 to 24 months of age. aEEG also was compared with a standard EEG and with magnetic resonance imaging. RESULTS: The median upper margin of the widest band of aEEG activity in the control infants was 37.5 microV (range, 30-48 microV), and median lower margin was 8 microV (range, 6.5-11 microV). We classified the aEEG background activity as normal amplitude, the upper margin of band of aEEG activity >10 microV and the lower margin >5 microV; moderately abnormal amplitude, the upper margin of band of aEEG activity >10 microV and the lower margin </=5 microV; and suppressed amplitude, the upper margin of the band of aEEG activity <10 microV and lower margin <5 microV. Recordings were analyzed further for the presence of seizures, defined as periods of sudden increase in voltage accompanied by a narrowing of the band of aEEG activity. Tests of interobserver variability showed excellent agreement both for assessment of amplitude (kappa statistic = 0.85) and for identification of seizures (kappa statistic = 0.76) There was a close relationship between the aEEG and subsequent outcome: 19 of 21 infants with a normal aEEG finding were normal on follow-up at 18 to 24 months of age, whereas 27 of 35 infants with a moderately abnormal or suppressed aEEG and/or seizures died or developed neurologic abnormalities. Thus, aEEG predicted outcome with a sensitivity of 0. 93, a specificity of 0.70, positive predictive value of 0.77, negative predictive value of 0.90, and the likelihood ratio of a positive result of 3.1 and a negative result of 0.06. For the 24 infants studied within 12 hours of birth, the corresponding results were sensitivity, 1.0; specificity, 0.82; positive predictive value, 0.85; negative predictive value, 1; likelihood ratio of a positive result, 5.5; and likelihood ratio of a negative result, 0.18. CONCLUSION: The aEEG is a simple but accurate and reproducible clinical tool that could be useful in the assessment of infants with encephalopathy.

Asphyxia Neonatorum↗