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PubMed2002

Assessment of the utility of paediatric electroencephalography.

Electroencephalography (EEG) is an important tool in investigating children with neurological disorders, particularly epilepsy. The objectives were to examine the relationship between clinical indications and EEG results, and assess the predictability of a normal result. 438 consecutive paediatric EEGs were included prospectively. One certified electroencephalographer (EEGer) reviewed EEG requisitions and recorded his prediction of a normal result. EEGs were reviewed separately and the relationship between the clinical indications and EEG abnormalities was recorded. The children's mean age was 5 years (SD 4.2). Paediatric neurologists ordered 32% of EEGs. The first EEG was studied in 65% of cases. Overall, 55% of the EEGs were abnormal. Repeat EEGs were twice as likely to be abnormal (95% CI 1.3-3, P= 0.001). Established epilepsy, using antiepileptic drugs, and sleep record, highly correlated with an abnormal result ( P< 0.0001). The EEGer predicted 26% of the EEGs to be normal. A normal EEG was correctly predicted in 97% of non-epileptic paroxysmal events, however, normalization of EEG was correctly predicted in only 54% of children with seizures. EEGs of 15 (3.4%) children with epilepsy revealed unexpected findings that completely changed their management. To conclude, a normal EEG is highly predictable in non-epileptic paroxysmal events. EEGs of children with epilepsy are not predictable and may yield unexpected results.

Adolescent↗

PubMed1979

Pharmaco-electroencephalography: the value of quantified EEG in psychopharmacology.

One of the first routine applications of quantitative EEG analysis was in the field of human psychopharmacology. As early as the 1960's, quantitative techniques, mainly period and amplitude integration analyses or analogue filtering, were successfully applied to EEG data with the aim of quantifying and objectifying changes induced by psychoactive medidation. Thus, step by step, a new research field, pharmacoelectroencephalography, was developed. Many other sophisticated new techniques have been described in great detail from the engineering viewpoint. However, due to the language barriers common between representatives of the various disciplines involved, it is still difficult to view them in context with the experimental design as a whole. Therefore, based on examples taken from our routine work, an attempt is made to give a balanced judgement on the value of such techniques in pharmaco-electroencephalography, and their contribution to the CNS pharmacology.

Arousal↗

PubMed2005

Prolonged confusional state following electroconvulsive therapy--diagnostic clues from serial electroencephalography.

INTRODUCTION: Cognitive impairment occasionally occurs after electroconvulsive therapy (ECT) and usually resolves within a few days. Any prolonged cognitive alterations or confusional states may have additional causes and require extensive diagnostic effort. Since cognitive dysfunction can also be caused by ictal states, electroencephalography (EEG) is an essential tool for these conditions. METHODS: We report on a female patient with pharmacotherapy resistant major depression who had been treated by a series of ECT and subsequently developed severe confusion and fluctuating amnesia. RESULTS: Laboratory and neuroimaging examinations were normal, however, EEG revealed a severe intermittent slowing with rhythmic high amplitude delta-/theta-activity and sporadic bitemporal sharp waves. Oral application of 1 mg lorazepam led to a sudden improvement of EEG abnormalities. Consequently, non-convulsive status epilepticus (NCSE) was suspected and the patient was regularly treated with lorazepam, accordingly. Clinically the confusional and amnesic symptoms declined, whereas serial EEG recordings showed a further improvement and normalization of brain electric activity. CONCLUSION: Routine EEG is an indispensable tool in patients with sudden deterioration of cognitive functions and unclear neuropsychiatric symptomatology. A testing dose of lorazepam can help to classify EEG abnormalities in terms of ictal EEG patterns.

Amnesia↗

PubMed1991

Predictive value of pharmaco-electroencephalography in early human-pharmacological evaluations of psychoactive drugs. First example: savoxepine.

The present paper forms the first part of a contribution to a comprehensive critical evaluation of the use of pharmaco-electroencephalography (pharmaco-EEG) as an instrument in the evaluation of pharmacodynamic effects of psychoactive drugs in man and further prediction of therapeutic effects by utilizing partial effects in a clinical pharmacological model situation. The basic principles and the methodological approaches are described first, prior to discussing the possibilities and limitations of the pharmaco-EEG in postulating hypotheses about therapeutic efficacy of psychoactive drugs in man. The discussion rests upon the findings with three selected new psychoactive drugs (savoxepine, levoprotiline and maroxepine), presented in this (Part I) and subsequent (Part II and III) reports. In this report results obtained with savoxepine, a novel tetracyclic compound, are described. Convergent evidence for antipsychotic potential of this drug has emerged from preclinical and pharmaco-EEG studies, subsequently corroborated by the first open trials in patients suffering from acute episodes of schizophrenia. In the pharmaco-EEG study a single dose of 0.5 mg savoxepine was tested in 15 healthy subjects with comparison to chlorpromazine (75 mg) and placebo. The experimental design was a threefold cross-over uncompleted block design with three consecutive trial days one week apart. Pharmaco-EEG was recorded under a high situational level of vigilance before 3 h and 6 h after drug administration. The recording was performed by means of 12 electrodes placed in the frontal, central, parietal and occipital regions. EEG-maps were constructed after power spectral analysis of absolute power changes in predetermined frequency bands within the range 0.5 to 30.0 Hz. The findings indicated EEG effects of savoxepine similar to those of chlorpromazine. In the tested dosage, however, savoxepine showed higher potency, later maximum (6 h) of the effect and lower sedative potential. Clinical trials performed in two centres and in, altogether, 28 acutely psychotic patients indicated antipsychotic activity of the drug in a low range of doses (on average, 0.1 to 0.9 mg/d). Even though the antipsychotic efficacy of savoxepine remains to be confirmed in controlled studies, the results favour the hypothesis that pharmaco-EEG has a value in predicting the quality of action of a new drug in man. Results also favour the complementary use of pharmaco-EEG in human pharmacology testing in order to objectively assess central effects of drugs and rationally estimate the doses for therapeutic trials.

Antipsychotic Agents↗

PubMed1994

The utility of electroencephalography and cerebral computed tomography in children with mild and moderately severe closed head injuries.

The utility of electroencephalography and computed tomography has been studied in a prospective follow-up study of 54 children with mild and moderately severe closed head injuries. EEG and CT scan were recorded in the acute phase. Furthermore the duration of coma and of post-traumatic amnesia were registrated. During a two years follow up period the presence of residual disorders in various faculties was evaluated at fixed time intervals after discharge. The data have been subjected to correlation analyses to study the relation of EEG and CT scan findings with the severity of the trauma and with the occurrence of longterm sequelae. Both the EEG and the CT scan abnormalities are found to correlate appreciably with the degree of severity and with the occurrence of, in particular, long-term sequelae in the fields of neurological disturbances and school performance. It is concluded that EEG and CT are useful diagnostic tools in children with mild and moderately severe closed head injuries.

Adolescent↗

PubMed2003

Epilepsy evaluation by electroencephalography and magnetoencephalography in Lafora-body disease: a case report.

UNLABELLED: Lafora-body disease (LBD) is a rare neurometabolic disorder of autosomal recessive inheritance associated with progressive myoclonic epilepsy. We report here the first description of ictal and interictal recording by electroencephalography (EEG) and magnetoencephalography (MEG) of a 15-y-old girl suffering from LBD. CONCLUSIONS: Complementary use of MEG and EEG might be of future help to the clinician in better defining the pathophysiology of complex seizures, and also in patients with progressive neurological disorders, despite the poor prognosis of syndromes such as LBD.

Adolescent↗

PubMed1982

Hereditary Pick's disease: second re-examination of the large family and discussion of other hereditary cases, with particular reference to electroencephalography, a computerized tomography.

A large family with Pick's disease was re-examined after twenty years. Five new cases were found, one in the fourth and four in the fifth generation. This family now includes 25 patients with the clinical diagnosis Pick's disease, proven by autopsy in 14, and 7 patients in whom the same diagnosis was considered likely, over six generations. The additional information strongly supports the previously postulated dominant mode of inheritance in this family. In connection with the possible hereditary nature of Pick's disease in general, data on reported families in which the disease occurred in two or more generations and unpublished data on three other families are discussed. Since the diagnosis Pick's disease was certain in affected members of this family, the value of electroencephalography and computerized tomography could be assessed. Persons at risk but without clinical signs of the disease were investigated in the same way, and in 4 cases out of 12, distinct frontal atrophy was found. In one of these cases clinical signs of Picks disease became manifest a year after the investigation.

Brain↗

PubMed2001

Predictability of processed electroencephalography effects on the basis of pharmacokinetic-pharmacodynamic modeling during repeated propofol infusions in patients with extradural analgesia.

BACKGROUND: Pharmacokinetic-pharmacodynamic (PKPD) modeling can be used to characterize the concentration-effect relation of drugs. If the concentration-effect relation of a hypnotic drug is stable over time, an effect parameter derived from the processed electroencephalographic signal may be used to control the infusion for hypnosis. Therefore, the stability of the propofol concentration-electroencephalographic effect relation over time was investigated under non-steady state conditions. METHODS: Three propofol infusions (25 mg x kg(-1) x h(-1) for 10 min, 22 mg x kg(-1) x h(-1) for 10 min, and 12.5 mg x kg(-1) x h(-1) for 20 min) were administered to 10 patients during extradural analgesia. Each successive infusion was started immediately after the patient had regained responsiveness after termination of the preceding infusion. Electroencephalography was recorded from bilateral prefrontal to mastoid leads. Electroencephalographic amplitude in the 11- to 15-Hz band and the Bispectral Index were used as electroencephalographic effect variables. PKPD parameters were calculated with use of parametric and nonparametric models based on electroencephalographic data and arterial propofol concentrations derived during the initial infusion, and these were used to predict electroencephalographic effect during the subsequent infusions. The predictability of the electroencephalographic effects was determined by the coefficient of determination (R2) and of the -2 log likelihood of the sequential infusions. RESULTS: The direction of electroencephalographic changes in response to the infusions was reproducible. Although PKPD parameters could be estimated well during the initial infusion (median [range] parametric R2 = 0.74 [0.56-0.95] for electroencephalographic amplitude and 0.90 [0.27-0.99] for Bispectral Index), none of the modeling techniques could predict accurately the electroencephalographic effect during subsequent infusions (R2 = 0.00 [-0.31-0.46] for electroencephalographic amplitude and 0.15 [-.46-0.57] for Bispectral Index; P < 0.01). CONCLUSIONS: The relation between blood propofol concentrations and the electroencephalographic effect under non-steady state conditions is not stable over time and is too complex to be modeled by any of the applied PKPD models.

Adult↗

PubMed1989

Usefulness of computerized electroencephalography in diagnosing, staging and monitoring AIDS-dementia complex.

One hundred and one subjects, with various degrees of HIV infection, were enrolled in a longitudinal study aimed at evaluating the correlation between clinical and instrumental findings in the development of HIV-related subacute encephalitis. The method used was electroencephalography coupled with computerized spectral analysis (EEG-CSA) and mapping. The findings recorded by this method were compared with those obtained by computed tomography (CT) scan and neurological examination. The EEG-CSA findings were divided into four categories according to their severity. EEG-CSA was shown to be very sensitive in detecting the first signs of a forthcoming neurological disease. Following 11 months of observation, 22 out of 40 (55%) neurologically asymptomatic individuals who, at the beginning of the study showed some EEG-CSA abnormalities, had clinical evidence of a subacute encephalitis whereas only two out of 37 (5.4%) subjects who were previously free of EEG-CSA abnormalities had some signs of neurological disease (P less than 0.001) after the same period. Of those remaining who were already symptomatic when the study started, the neurological progression of HIV infection was also monitored by EEG-CSA.

Acquired Immunodeficiency Syndrome↗

PubMed1998

Spectral analysis of electroencephalography changes after choking in judo (juji-jime).

PURPOSE: The present study was carried out to investigate possible electroencephalographic changes induced by choking in judo (shime-waza) by means of spectral analysis and brain mapping. METHODS: Power spectral changes in Electroencephalography (EEG) were recorded in six experienced judoka who underwent a choking trial with a "shime-waza choking" technique called juji-jime. RESULTS: A significant increase of global field power in the delta- and theta-range occurred, while physiological alpha-power decreased. These changes in the low-frequency range reached a statistically significant level within a time span up to 20 s after choking, which was performed at an average choking time of 8 s. In no case did choking provoke neuropsychological symptoms. Yet, spectral EEG-analysis revealed subclinical changes of brain function. CONCLUSIONS: Choking in judo may induce subclinical electroencephalographic perturbations. The extent and duration can be objectified by means of spectral analysis of EEG data, global field power computation, and brain-mapping representation.

Airway Obstruction↗

PubMed1989

The use of electroencephalography and brain protection during operation for basilar aneurysms.

Intraoperative monitoring with electroencephalography and the use of brain protection with steroids, phenytoin, mannitol, and pentobarbital or etomidate were evaluated in 15 patients undergoing operation for an aneurysm of the upper basilar artery. One patient harbored a basilar trunk aneurysm, 1 an aneurysm of the proximal posterior cerebral artery, 3 an aneurysm of the superior cerebellar artery, and 10 an aneurysm at the basilar tip. The size of the aneurysms varied between 5 and 30 mm. Subarachnoid hemorrhage was the symptom exhibited in 12, mass effect the symptom in 2, and 1 patient was asymptomatic but had an angiogram because of amaurosis. There were 9 patients with multiple aneurysms, 5 of whom had aneurysms of the bilateral anterior circulation. Four patients underwent operation early. In 2 patients, the basilar artery was the sole or main blood supply of the whole brain. All patients except the one with the basilar trunk aneurysm were operated on via a transsylvian approach. All patients received 500 to 800 mg of phenytoin and 10 to 20 mg of dexamethasone shortly before and during surgery, and mannitol (0.8 g/kg) 15 minutes before the induction of hypotension or temporary clipping. Three patients showed slowing of electrical activity over the right hemisphere as a result of retraction of the internal carotid artery; with repositioning of the retractor, this disappeared within 10 minutes. Electrocortical silence was induced in 8 patients; this was in anticipation of prolonged moderate hypotension in 2, short deep hypotension in 2, temporary clipping of major vessels--including the basilar artery--in 2, and a combination of deep hypotension combined with temporary clipping in 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1998

Source localization determined by magnetoencephalography and electroencephalography in temporal lobe epilepsy: comparison with electrocorticography: technical case report.

OBJECTIVE AND IMPORTANCE: Source modeling by magnetoencephalography (MEG) and electroencephalography (EEG) may be useful techniques for noninvasive localization of epileptogenic zones for surgery in patients with partial seizures. CLINICAL PRESENTATION: Simultaneous recordings of MEG and EEG, obtained in two patients, were coregistered on each patient's magnetic resonance image for direct comparison of these two methods with intracranial electrocorticography. TECHNIQUE: The average difference between MEG and EEG for localization of the same interictal spikes was approximately 2 cm in one patient and 3.8 cm in the other patient. One patient experienced a complex partial seizure during testing, which permitted comparison between interictal and ictal source localization by both MEG and EEG. The EEG ictal localization differed from the interictal one, whereas the MEG ictal and interictal localizations were more similar. In this patient, the MEG interictal source seemed to localize close to the ictal source, whereas EEG did not. The patients underwent temporal lobectomy after electrocorticography, and the results were compared with the findings of MEG and EEG. Although the results of both techniques agreed with the findings of electrocorticography, in one patient the MEG localization seemed to be more accurate. Both patients experienced good surgical outcomes. CONCLUSION: Both MEG and EEG source localization can add useful and complementary information for epilepsy surgery evaluation. MEG seemed to be more accurate than EEG, especially when comparing interictal versus ictal localization. Further study is needed to evaluate the validity of source localization as useful noninvasive techniques to localize the epileptogenic zone.

Adolescent↗

PubMed1995

Inter-ictal brain SPET in frontal epilepsy: correlations with stereo-electroencephalography.

Single photon emission tomography (SPET) imaging holds promise for localization of the site of extratemporal seizures, but limited data currently exist; in particular, correlations with stereo-electroencephalography (S-EEG) have not been made. Ten patients aged 14-44 years (mean 25 years) with a proven frontal or central epilepsy by S-EEG and post-surgical follow-up were studied retrospectively: 7 patients had frontal cortectomy and one patient had a callosotomy for bifrontal epilepsy. All patients underwent clinical, inter-ictal and ictal video-EEG, computed tomography scan and/or magnetic resonance imaging, SPET and S-EEG examinations. SPET was performed inter-ictally, while on usual epileptic medications, using 99Tcm-HMPAO (n = 4) or 123I-IMP (n = 6) as the perfusion tracer. The SPET images were evaluated independently by two observers, blind to any data other than the diagnosis of frontral or central epilepsy. Localization of inter-ictal SPET hypoperfusion was compared with the epileptogenic (EZ), irritative (IZ) and lesional (LZ) zones, as defined by S-EEG. Six patients showed structural frontal abnormalities. One patient had normal SPET and one had a contralateral hypoperfusion. Therefore, concordance of sides was found in 8 of 10 patients (including one with bilateral SPET and S-EEG abnormalities). The hypoperfusion was equal to or larger than the EZ + IZ + LZ in 6 patients (5 had a frontal lesion). SPET hypoperfusion was smaller than the EZ in one patient, and different from the EZ, IZ and LZ in two patients. Although this was a retrospective study, it provides qualitative data regarding the significance of inter-ictal SPET abnormalities in frontal or central epilepsy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed2001

Combining median electroencephalography frequency and sympathetic activity in an index to evaluate opioid detoxification in patients.

During rapid opioid detoxification, increased sympathetic activity and a greater median frequency (MF) of activity on electroencephalography (EEG) have been reported. The purpose of this study was to evaluate a new index for detoxification that combines sympathetic activity and MF data. After informed consent was obtained, eight patients were sedated with propofol. The MF of EEG activity derived from frontal electrodes was determined. Heart rate variability was evaluated in 256-second segments by power spectral analysis, and sympathetic activity was determined by the low frequency component. The Hoffman Index for narcotic detoxification was weighted 70% to sympathetic activity and 30% to MF to normalize the difference in scales and to provide adequate weight to the sympathetic component. Opioid detoxification was produced by infusion of 25 mg naloxone for 30 minutes, followed by a 24-hour infusion of 1 mg per hour. The MF showed a rapid increase during high-dose infusion of naloxone, but the peak response occurred 1 to 2 hours later. Sympathetic activation and the Hoffman Index increased more slowly after the start of naloxone infusion, but peak increases in all components occurred at approximately the same time. The peak increases in Hoffman Index (110% of baseline), MF (260%), and sympathetic activity (304%) during administration of naloxone were significant and correlated with respect to time (r = 0.89-0.94). The Hoffman Index showed an early increase related to MF and a well-defined peak response indicative of sympathetic and MF activity. The behavior of the Hoffman Index in relation to the MF and sympathetic activity more clearly indicated the onset of opioid detoxification and the maximum response to opioid reversal than did MF or sympathetic activity alone.

Electrocardiography↗

PubMed2002

Cerebral injury predicted by transcranial Doppler ultrasonography but not electroencephalography during carotid endarterectomy.

When shunts are selectively used during carotid endarterectomy, the adequacy of collateral cerebral blood flow (CBF) after the carotid artery is clamped is determined by monitors based on different physiologic measurements. In this series of three patients, we used electroencephalography (EEG) to measure neuronal electrical activity and transcranial Doppler ultrasonography (TCD) to measure CBF velocity. In each of our cases, the EEG was unchanged from preclamp values, while TCD CBF velocity was dramatically reduced. All three patients had transient neuropsychometric or neurologic changes after surgery, which resolved.

Aged↗

PubMed1993

Electroencephalography and magnetoencephalography in epilepsy and nonepileptic disorders.

Recent advances in electroencephalography (EEG) and magnetoencephalography are reviewed. Their relevance to epileptic and nonepileptic conditions is considered. The use of intensive video-EEG monitoring for the study or diagnosis of epilepsy is addressed. Studies using invasive EEG procedures for seizure analysis with or without surgical therapy are described. The integration of EEG with computer technologies is increasing, and studies using digital EEG recording and quantitative analysis in Alzheimer's disease and other disorders are reviewed. Environmental and behavioral effects on EEG are considered. The role of EEG in sleep-related electrophysiological monitoring is presented. Progress in magnetoencephalography is described, but as a newer technology its usefulness in epilepsy and other disorders remains to be proved, especially for clinical applications.

Alzheimer Disease↗

PubMed2001

Current trends in electroencephalography.

Several recent articles re-emphasize the value of clinical electrophysiology: in localizing epileptogenesis, predicting effectiveness of epilepsy surgery, and disclosing a mechanism of benign Rolandic epilepsy of childhood.A review of the role of EEG in the diagnosis of epilepsy indicated that epileptiform activity will appear in 50% of initial awake recordings of adults with epilepsy and in 85% of subjects undergoing two recordings. This contrasts with the appearance of spikes in only 4 of 1000 normal persons. Several studies focused on the value of electroencephalography in extratemporal epilepsy: 62% of patients with neocortical epilepsy had at least one localizing ictal EEG; occipital and temporal neocortical seizures were localized in a greater proportion than frontal or parietal attacks. Interictal spikes, if unifocal, always arose from the epileptogenic region in a study of their seizure localizing value. Such congruence augured for better seizure control by focal resection in two studies reviewed herein. Studies indicating the value of interictal temporal lobe spikes and scalp-recorded seizures in lateralising a temporal seizure focus are reviewed. One study found EEG to be slightly more reliable for lateralization of temporal epileptogenesis than MRI. In patients with benign Rolandic seizures, enhanced motor evoked potentials (MEPs) were obtained from transcranial magnetic stimulation when this was applied 50-80 msec after electrical stimulation of the thumb whereas this interval inhibited the MEP in normal subjects. This suggests that afferent cutaneous input abnormally and synchronously activates a large population of sensory neurons; such activation is subsequently transmitted to the motor cortex to produce the focal spikes in this condition.Finally, advances in non-invasive technology have redefined and limited the need for invasive monitoring in children with intractable seizure disorders.

Cerebral Cortex↗

PubMed2005

Toward the substitution of invasive electroencephalography in epilepsy surgery.

The authors compared the localization accuracy of interictal magnetoencephalography (MEG) with ictal and interictal invasive video electroencephalography (VEEG) in identifying the epileptogenic zone in epilepsy surgery candidates. Forty-one patients, 29 with temporal lobe epilepsy (TLE) and 12 with extratemporal lobe epilepsy (ETLE), participated. Only patients with interictal changes during the MEG recordings were included. A comparison of the accuracy of invasive VEEG and MEG seizure zone identification was based on the degree of overlap between the location of the actual surgical resection and the zone identified by each method, and the success of surgery in reducing seizure activity. No statistical differences were observed between the accuracy of invasive VEEG and MEG in determining the location of the seizure zone across TLE and ETLE cases. Invasive VEEG and MEG localization judgments were correct in 54% and 56% of the cases, respectively. Separate group analyses suggested that MEG may be less beneficial relative to invasive VEEG in ETLE than TLE cases. MEG is of statistically equivalent accuracy to invasive VEEG, despite the fact that its use has not reached optimal conditions. The authors predict the replacement of the more invasive procedure with MEG in the near future for TLE cases, subsequent to the optimization of the conditions under which preoperative MEG is performed.

Adolescent↗