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PubMed2002

The use of electroencephalography in psychiatry of the medically ill.

The psychiatrist considering recommending an EEG should look for acute changes in the history or examination suggestive of an organic cause. If he or she judges that the EEG will help to clarify or confirm the diagnostic impression already formulated, it is worth considering whether adding provocative maneuvers could increase the yield. The authors cannot overemphasize the importance of using the EEG in correlation to further inform old-fashioned clinical detective work already in process, particularly when the EEG could rule out a potential organic contributor to a psychiatric phenotype. For routine screening without an elevated index of suspicion or for thoughtless "fishing expeditions," EEG results will surely disappoint.

Adult↗
PubMed2001

Hippocampus in relation to mental sweating response evoked by memory recall and mental calculation: a human electroencephalography study with dipole tracing.

Mental-sweating response (MSR) was observed in the palm when the subject was asked to perform a mentally stressful task such as memory recall or mental calculation. About 4 s before the development of MSR, small MSR-related wavelets (MSR wavelets) and large waves were randomly generated on electroencephalograph. After differentiating the two types of waves, we calculated locations of the current dipole of MSR wavelets using the two-dipole model of the SSB/dipole tracing method. The result showed that one current dipole of MSR wavelets was consistently located in the hippocampus while the other dipole was widely dispersed in the cortex during memory recall and mental calculation.

Adult↗
PubMed1999

Recurrent seizures and hippocampal sclerosis following intrahippocampal kainate injection in adult mice: electroencephalography, histopathology and synaptic reorganization similar to mesial temporal lobe epilepsy.

Human mesial temporal lobe epilepsy is characterized by hippocampal seizures associated with pyramidal cell loss in the hippocampus and dispersion of dentate gyrus granule cells. A similar histological pattern was recently described in a model of extensive neuroplasticity in adult mice after injection of kainate into the dorsal hippocampus [Suzuki et al. (1995) Neuroscience 64, 665-674]. The aim of the present study was to determine whether (i) recurrent seizures develop in mice after intrahippocampal injection of kainate, and (ii) the electroencephalographic, histopathological and behavioural changes in such mice are similar to those in human mesial temporal lobe epilepsy. Adult mice receiving a unilateral injection of kainate (0.2 microg; 50 nl) or saline into the dorsal hippocampus displayed recurrent paroxysmal discharges on the electroencephalographic recordings associated with immobility, staring and, occasionally, clonic components. These seizures started immediately after kainate injection and recurrid for up to eight months. Epileptiform activities occurred most often during sleep but occasionally while awake. The pattern of seizures did not change over time nor did they secondarily generalize. Glucose metabolic changes assessed by [14C]2-deoxyglucose autoradiography were restricted to the ipsilateral hippocampus for 30 days, but had spread to the thalamus by 120 days after kainate. Ipsilateral cell loss was prominent in hippocampal pyramidal cells and hilar neurons. An unusual pattern of progressive enlargement of the dentate gyrus was observed with a marked radial dispersion of the granule cells associated with reactive astrocytes. Mossy fibre sprouting occurred both in the supragranular molecular layer and infrapyramidal stratum oriens layer of CA3. The expression of the embryonic form of the neural cell adhesion molecule coincided over time with granule cell dispersion. Our data describe the first histological, electrophysiological and behavioural evidence suggesting that discrete excitotoxic lesions of the hippocampus in mice can be used as an isomorphic model of mesial temporal lobe epilepsy.

Animals↗
PubMedDate not supplied

The function of 'brain waves': a cybernetic model of electroencephalography.

Electroencephalograms recorded from sleeping subjects are reinterpreted, from first principles, to explain the relationship between the observed wave-forms and cerebral processes. The manifestations of narcolepsy, namely, sleep paralysis, hypnopompic hallucinations and cataplexy are consistent with a hypothesis that the disorder is the result of entrainment of cerebral waves, causing almost instantaneous descent into a REM sleep state.

Cataplexy↗
PubMedDate not supplied

The use of computer analysis for diagnosis in routine electroencephalography.

1. Frequency power spectra and mutual coherence functions of 8 stimulatenously recorded E.E.G. derivations have been computed in approximately 500 non-specially selected patients referred to the department for E.E.G. recording. 2. On basis of the data obtained some provisionnal conclusions have been drawn, the most important of those being that the analyses contribute significantly and in some cases essentially to the understanding of the E.E.G. and therefore should be carried out in all E.E.Gs recorded to our department. 3. It has been observed that mu rhythms and beta rhythms appear to be essentially different from alpha rhythms by exhibiting no bilateral coherence whereas alpha rhythms almost invariably are considerably bilateral coherent.

Alcoholism↗
PubMedDate not supplied

[Contribution of electroencephalography in tranquilizer withdrawal syndromes].

Withdrawal syndromes after discontinuation of benzodiazepine or meprobamate administration are rarely observed, in spite of the large number of prescriptions given. Similar manifestations are noted as after barbiturate withdrawal, and appear 1 to 10 days after sudden interruption of prolonged treatment at high doses. The 6 cases reported include 4 patients with withdrawal syndromes after benzodiazepines (diazepam, oxazepam, lorazepam) and 2 after meprobamate. No evidence of epilepsy was found in the patients, who were hospitalized for treatment after suicidal attempts, or medication overdosage (phenothiazine) in one case. Withdrawal symptoms appeared between the 2nd and 7th day with confusion and/or generalized convulsions and paroxystic changes with slow spike-wave type on EEG tracings. In such cases, precise information must be obtained about previous medication in order that it may be readministered and the diagnosis of epilepsy avoided in patients with withdrawal symptoms.

Adult↗
PubMed1982

[Indication of tele-electroencephalography coupled to videoscopy in the study of higher functions in the epileptic child].

An examination procedure, including psychometric tests performed during a tele-encephalographic recording coupled to videoscopy, has been applied twice to 32 epileptic children in a double-blind study appreciating the clinical and electroencephalographic effects of an antiepileptic drug. The psychometric test scores were influenced by the presence of subclinical spikes and spike-and-wave discharges or by seizures of very short duration eluding investigation of the psychologist. It is shown that psychometric test results can be interpreted in a different way according to the procedural choice. Without simultaneous tele-encephalographic and videoscopic documents, the anti-epileptic drug tested in the study (sodium valproate) would have been considered as having a direct favorable action on superior functions appreciated by performance on the tests used. However, it has been possible to demonstrate that the improvement is consecutive to the beneficial effect of the drug in relieving seizures and subclinical spikes and spike-and-wave discharges.

Adolescent↗
PubMed1983

[Computerized quantitative topo-electroencephalography].

A method is described which has been developed to topographically display the values of spectral EEG analysis from 11 electrodes on each hemisphere and 5 electrodes on the midline. The EEG from 16 channels at a time is multiplexed and sampled at 3.2 kHz. From power spectra averaged every 10 sec for 5 min a few spectral parameters are computed among which are the spectral intensities within the delta, theta, alpha and beta bands. The whole values are then displayed on maps representing lateral views of cerebral hemispheres by means of spectral iso-intensity surfaces with extrapolation of the intermediate points. Different spectral intensities are coded by means of different gray levels. These maps clearly illustrate the topographical distribution of EEG rhythms and their peculiarities related to the side of the head recorded.

Alpha Rhythm↗
PubMed1983

[Topographic aspects of drug-induced fast rhythms in quantitative topo-electroencephalography].

The topographical aspects of fast rhythms induced by different psychotropic drugs have been studied in patients by means of a previously described method. This method is based on the spectral analysis of 28 EEG channels over both cerebral hemispheres. The spectral parameters, computed over 2 min 40 sec, are put into a data base. The clinician can then decide which of these parameters will be extracted from the data base and then displayed by means of maps on a graphic terminal. Those maps are useful for immediate comparison not only of the fast rhythms' characteristic values but also of those from other spectral bands. As quantitative EEG analysis is more and more frequently used in psychotropic drug studies, a good knowledge of the topography of the rhythms induced by these drugs will help in the selection of the most useful derivations.

Adult↗
PubMed1986

[Methodology, limitations and value of mapping in electroencephalography].

Data processing is mandatory for EEG mapping. After having used a correct filter and ADC, spectral analysis is completed by interpolating between the spectral values obtained on each recording point to allow a sufficient number of values to be expressed in a grey or color scale on the skull projection plane. The obtention of valid results implies extreme care in data recording and processing. Transitory events (paroxysmal bursts) cannot be detected by spectral analysis. Nevertheless, EEG spectral data mapping is a very good technique to show abnormal EEG focuses in neurology, to study all sorts of neuropsychological reactivities, to follow the evolution of tracings during normal or abnormal aging, metabolic diseases or drug effects.

Aging↗
PubMed1987

[Complementarity of x-ray computed tomography of staged stereotaxic biopsies and of stereo-electroencephalography in the spatial definition of intracranial lesions].

This study concerns 180 patients (132 M; 48 F) (age: 2 to 69 years; m: 33 years) who underwent stereotactic procedures according to the methodology of Talairach and Szikla. Such procedures (stereotactic and stereoscopic angiography in all cases, and ventriculography in 81%) should permit a correct spatial definition of intracranial lesions. The informations provided by the angiography (normal in 7%) and by the ventriculography (normal in 11%) are complementary to those yielded by the TDM and permit an easier and safe stereotactic approach to the lesions. In 43% of patients the lesions were deep-seated (basal ganglia: 24; sellar region: 19; thalamo-peduncular: 13; brain stem: 6, etc.). The histological examination showed: low-grade gliomas in 43%; glioblastomas in 21%; non tumoral lesions in 17%. A precise diagnosis couldn't be obtained in 3.8%. The data provided by the stereo-EEG (in 11 patients suffering also of severe drug-resistant partial epilepsy) did not permit, alone, an histological diagnosis, excepted when electrodes explored a solid tumor. Two patients had a neurological impairment, and two died (one for extracerebral reasons). The authors consider that the TDM data and the informations given by the stereotactic procedures are complementary for obtaining valuable informations on the spatial organization of intracranial lesions and choosing the best treatment.

Adolescent↗
PubMed2001

Relation between the date of cyst formation observable on ultrasonography and the timing of injury determined by serial electroencephalography in preterm infants with periventricular leukomalacia.

The aim of this study was to clarify the relation between the date of cyst formation and the timing of injury in preterm infants with periventricular leukomalacia in order to address the issue of whether or not we can determine the timing of injury on the basis of ultrasonographic findings. We studied 33 preterm infants with cystic periventricular leukomalacia, the gestational ages being 32 weeks or less. As 27 of them exhibited either acute or chronic stage abnormalities in the initial electroencephalogram, the timing of injury was presumed to be before or around birth. For the remaining six infants, the timing of injury was considered to be postnatal in two infants, and was not determined in another four. The median date of cyst formation was 18 days of age (range, 10-39 days) in the 27 infants with abnormal initial electroencephalograms. For these 27 infants, the gestational age did not influence the date of cyst formation. In contrast, the date of cyst formation was significantly earlier in infants with widespread cysts than in those with localized cysts. In conclusion, it is difficult to determine the timing of injury from ultrasonographic findings, because the range of the date of cyst formation on ultrasonography was very wide among infants whose timing of injury was not greatly different.

Adult↗
PubMed2004

Treatment and outcome in patients with febrile convulsion associated with epileptiform discharges on electroencephalography.

The aim of this study is to determine the efficacy of prophylactic treatment for patients with febrile convulsions (FCs) in whom electroencephalograms (EEGs) revealed epileptiform discharges. We retrospectively investigated 43 patients who met the following criteria: (a) at least one FC during the study period; (b) epileptiform discharges were first recognized; (c) no unevoked seizures before epileptiform discharges were first seen; (d) normal psychomotor development and no neurological abnormality; and (e) follow-up >3 years. The clinical characteristics, treatment, and a later occurrence of FCs or unevoked seizures were studied. EEGs revealed focal epileptiform discharges in 25 patients and generalized ones in 18. There was no significant difference in the rate of recurrence of FC or occurrence of unevoked seizures between those with focal and generalized epileptiform discharges. No prophylaxis was performed in ten patients, 14 patients being treated with intermittent diazepam and 19 with a daily anticonvulsant. The rate of recurrence of FC was not significantly different between patients with and without prophylaxis. Unevoked seizures were only observed in two patients undergoing daily treatment. Intermittent or daily anticonvulsant therapy will not reduce the risk of recurrence of FCs or later development of unevoked seizures in patients with FC with epileptiform discharges.

Anticonvulsants↗