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PubMedDate not supplied

[Computerized electroencephalography in acute cerebral ischaemia (author's transl)].

Physiopathological, clinical and therapeutical problems of acute cerebral ischaemia and brain infarction are briefly discussed. In the opinion of the Authors, a first valuable approach to the diagnosis and treatment of these conditions is afforded by the computerized electroencephalography (Berg Fourier Analysis). This investigations proved to be a safe, easy and reliable tool for testing and monitoring the effectiveness of individually selected drugs in early phases of cerebral ischaemia.

Acute Disease↗

PubMed1995

Seizure-induced transient hippocampal abnormalities on MR: correlation with positron emission tomography and electroencephalography.

We report transient focal abnormalities on MR in a patient having frequent electrographic seizures that were not obvious clinically. Marked mass effect (confirmed with volumetric studies) and abnormal T2 signal intensity in the right hippocampal region correlated with electroencephalographic ictal activity and with increased positron-emitting radiotracer uptake in the medial temporal lobe. The follow-up MR 2 months later, after electroencephalography findings normalized, revealed no hippocampal abnormalities.

Aged↗

PubMed1995

[The practical benefits of magnetoencephalography in comparison with electroencephalography in a patient with epilepsia partialis continua].

A concurrent recording of electroencephalography (EEG), magnetoencephalography (MEG) and electromyography (EMG) was carried out in a patient with epilepsia partialis continua. He had continuous clonic jerks in his right hand and fingers. The EMG electrodes were placed on the thumb of his right hand. We observed numerous MEG spikes in the left central region and about half of them were accompanied by EMG potentials with a latency of about 20 msec. The EEG spikes appeared less frequently, had low amplitudes, and had unclear morphologies and further, no clear association with EMG potentials. MEG spikes were more reliably associated with individual jerks, exemplified by EMG potentials, than the EEG spikes. The MEG spikes were sharper than EEG spikes and were about 20 msec wide. The intracranial dipole localization of the MEG spikes was estimated by overlaying the calculated generator sites on magnetic resonance images. It was found that the spikes converged along a line, presumably the central sulcus. The practical benefits of the MEG as a diagnostic tool in epilepsy are illustrated.

Adult↗

PubMed1994

Effects of atropine in the beagle dog measured by quantitative electroencephalography and regional cortical analysis.

A treatment-by-subjects design was used to identify and characterize quantitative electroencephalography (qEEG) changes, at rest and under stimulus conditions, in Beagle dogs given 3 dose levels of atropine sulfate. In general, total power, absolute delta and theta amplitudes increased, while relative beta contribution and spectral frequency 90 decreased, as increased levels of atropine were administered. Regional analysis of this qEEG dataset suggests cortical mapping and contour plot imaging can be done in the dog. Through statistical analysis and visual evaluation of regional patterns may be more acceptable for interpretation in regulatory toxicology studies until normative databases are developed.

Analysis of Variance↗

PubMed1994

Effects of altered arterial carbon dioxide tension on quantitative electroencephalography in halothane-anesthetized dogs.

Quantitative electroencephalography was assessed in 6 dogs anesthetized with 1.8% end-tidal halothane, under conditions of eucapnia, hypocapnia, and hypercapnia. Ventilation was controlled in each condition. Heart rate, arterial blood pressure, core body temperature, arterial pH, blood gas tensions, end-tidal CO2 tension, and end-tidal halothane concentration were monitored throughout the study. A 21-lead linked-ear montage was used for recording the EEG. Quantitative electroencephalographic data were stored on an optical disk for analysis at a later date. Values for absolute power of the EEG were determined for delta, theta, alpha, and beta frequencies. Hypocapnia was achieved by hyperventilation. Hypercapnia was achieved by titration of 5% CO2 to the inspired gas mixture. Hypercapnia was associated with an increase in the absolute power of the delta band. Hypocapnia caused an increase in the absolute power of delta, theta, and alpha frequencies. Quantitative electroencephalographic data appear to be altered by abnormalities in arterial carbon dioxide tension. Respiratory acidosis or alkalosis in halothane-anesthetized dogs may obscure or mimic electroencephalographic abnormalities caused by intracranial disease.

Animals↗

PubMed1993

Proconvulsant effect of ketotifen, a histamine H1 antagonist, confirmed by the use of d-chlorpheniramine with monitoring electroencephalography.

Ketotifen produced seizures in a 5-year-old boy with secondary generalized epilepsy (SGE) and allergic rhinitis. To confirm that the seizures were due to histamine H1 receptors blockade, d-chlorpheniramine was administered with monitoring electroencephalography (EEG). Administration of d-chlorpheniramine significantly increased the number of epileptic discharges in the patient, compared with those before administration. Plasma noradrenaline and dopamine levels were not affected by treatment with d-chlorpheniramine. These findings indicate that histamine H1 receptors blockade produced convulsions and increased epileptic discharges on EEG. Recently, several experimental reports have shown that histamine has an inhibitory role on convulsions through histamine H1 receptors. Experimental findings and present results show that histamine H1 antagonists have proconvulsant effects, especially in the developmental period. Thus, it is recommended that centrally-acting histamine H1 antagonists should be avoided in epileptic patients, especially in children of pre-school age.

Child, Preschool↗

PubMed1993

[Spike discharge detected by intra-arterial electroencephalography from intra-arterial guide wire in temporal lobe epilepsy].

The implantation of electrodes for intracranial electroencephalography (EEG) recording as presurgical evaluation of patients with intractable epilepsy is at present most important for planning epilepsy surgery. This method is most effective in temporal lobe epilepsy. We carried out intracranial EEG by means of insulated micro guide wire for endovascular surgery in two temporal lobe epilepsy cases, and spike discharges could be detected in lesional medial temporal lobe. Case 1 is a 29 year-old-male suffered from intractable complex partial seizure (CPS) for 18 years. He was diagnosed as left temporal lobe epilepsy and performed removal of amygdala, hippocampus, parahippocampal gyrus and fusiform gyrus. Case 2 is a 16 year-old-lady suffered from drug resistant CPS for 4 years. Under the diagnosis of right temporal lobe epilepsy, temporal lobectomy was performed. As the presurgical evaluation, under the implantation of subdural strip electrode in both cases, we carried intra-arterial EEG after angiography. Seeker Lite-10 guide wire was insulated with Tracker-10 unibody infusion catheter at sphenoidal portion of middle cerebral artery, and frequent interictal spike discharge was detected in lesional medial temporal lobes by two methods simultaneously.

Adolescent↗

PubMed1995

Electroencephalography in cerebral malaria.

Electroencephalography (EEG) was performed in 13 male patients with cerebral malaria during the first 24 hours of admission, using a 10-channel, 10-20 system EEG machine (6 montages, 20 minute duration). The EEG patterns were of theta and delta waves from both sides of cerebral hemisphere suggesting diffused cortical dysfunction. No epileptic pattern was found in patients who had seizures prior to, or after admission. The initial EEG performed on the day of admission did not show any specific pattern attributable to any pathological condition. It was also unable to predict the prognosis of the 2 dead patients. However, one cerebral malaria patient with left hemiplegia was subsequently found to have right basal ganglia hemorrhage in CAT scan, high amplitude delta waves and theta waves in the tracings of the right hemisphere. The study suggests that a single EEG data on admission can hardly give enough information for prediction of the clinical course and outcome of cerebral malaria. Serial EEGs probably provide more useful information regarding the prognostic signs in this group of patients. Nevertheless, EEG could be useful to rule out some cerebral pathology such as space occupying lesions, epilepsy or any other causes of unconsciousness that could produce similar cerebral symptoms in malaria patients.

Adult↗

PubMedDate not supplied

[Diagnostic value of electroencephalography and evoked potentials in monitoring brain maturation in children with febrile convulsions].

A group of 31 children aged 4-14 was presented with clinical manifestations of febrile convulsions, which after clinical examination, were followed--up in outpatient clinics during 1-12 year period. Together with continuous electroencephalographic monitoring, visual and somatosensory potentials were measured with the aim to stress a diagnostic significance of these neurophysiological methods for cerebral maturation assessment in children with febrile convulsions. Results reveal that electroencephalography (EEG) and somatosensory potentials (SEP) have higher diagnostic sensitivity compared to the visual ones (VEP). In 25 children (80.64%) SEP changes were registered in the form of prolonged central conductivity time (CCT) and EEG revealed changes in the form of slower cerebral activity and posterior theta activities fr. 4-7 Hz (P-O bilaterally) in 10 children (32.26%). Registered SEP changes, particularly prolonged CVP, as well as changes in the form of slower basic cerebral activity or posterior theta rhythm could be explained by slower maturation of some CNS regions. EEG and SEP findings show positive correlation with clinical findings and different diagnostic sensitivity, therefore their use in clinical follow-up of children with febrile convulsions is important.

Child↗

PubMed1995

Method for screening drug and chemical effects in laboratory rats using computerized quantitative electroencephalography.

A minimally-invasive method of quantitative electroencephalography (qEEG) that requires no anesthetics and parallels techniques of naturalistic stimulation was developed and validated for regulatory testing of drugs and chemicals in rats. Male and female Fischer 344 rats were utilized in a randomized-block design to measure qEEG target parameters associated with a range of cholinesterase inhibition. For this study, physostigmine was administered ip at doses of 0.05, 0.2 or 1.0 mg/kg, resulting in average cholinesterase inhibition in plasma (28, 38 and 70%), erythrocytes (19, 24 and 36%), and brain (2, 10 and 31%) which correlated well with increased total power and amplitude changes. Additional treatment-related effects consisted of decreased relative alpha and beta, increased relative delta, and a left-shift in the spectral-edge frequency. In a second study, male and female Sprague-Dawley rats were utilized in a treatment-by-subjects design to determine qEEG target parameter changes due to the M2 autoreceptor agonist oxotremorine. Repeated incremental doses (0.05, 0.1, 0.2 mg/kg; ip) of oxotremorine resulted in increased beta contribution, a right-shift in the spectral-edge frequency and decreased alpha contribution. These qEEG results with physostigmine and oxotremorine correlate well with receptor-specific and general muscarinic effects, making it a reliable contribution to analysis of agonist and antagonist effects of cholinergic compounds.

Alpha Rhythm↗

PubMed1996

Method for screening drug and chemical effects in laboratory rats using computerized quantitative electroencephalography.

Analysis of Variance↗

PubMed1997

[Some issues regarding the use of electroencephalography and brain evoked potentials in occupational medicine].

On the basis of the literature data, the practical value of electroencephalography (EEG) and tests of brain evoked potentials, particularly visual evoked potentials (VEP) and somatosensory evoked potentials (SSEP) in the diagnosis of occupational diseases of the nervous system is discussed. Electroencephalographic changes and the results of the evoked potential tests performed in persons exposed to organic solvents and heavy metals are analysed. The author postulates how the research in this field should be oriented and stresses the need to incorporate the method of evoked potentials into diagnostic procedures, especially in the case early symptoms of the nervous system dysfunction induced by occupational factors.

Electroencephalography↗

PubMed1998

Preictal SPECT in temporal lobe epilepsy: regional cerebral blood flow is increased prior to electroencephalography-seizure onset.

UNLABELLED: Peri-ictal SPECT provides unique information on the dynamic changes in regional cerebral blood flow (rCBF) that occur during seizure evolution and, thus, could be useful in clarifying the poorly understood interplay of the interictal and ictal states in human focal epilepsy. The regional hyperperfusion observed on ictal SPECT is generally believed to be a consequence of electrical seizure activity. However, recent studies using invasive long-term cortical CBF monitoring have demonstrated that rCBF changes occur up to 20 min prior to ictal electroencephalography (EEG) onset. Because of apparent technical difficulties, no preictal SPECT studies have been reported so far. Therefore, we present our results on two patients with temporal lobe epilepsy in whom preictal SPECT scans were performed fortuitously under continuous video-EEG monitoring control. METHODS: Technetium-99m-hexamethyl propyleneamine oxime was injected 11 min (Patient 1) and 12 min (Patient 2) before clinical and EEG seizure onset, as documented from simultaneous video-EEG monitoring in two patients with temporal lobe epilepsy. We obtained accurate anatomical reference of CBF changes visible on SPECT by a special coregistration technique of MRI and SPECT. RESULTS: Whereas interictal SPECT showed a hypoperfusion of the temporal lobe ipsilateral to the seizure focus, on preictal SPECT, a significant increase in rCBF in the epileptic temporal lobe could be observed. These rCBF changes were not accompanied by any significant changes of the ongoing EEG. CONCLUSION: Our study provides evidence that rCBF is increased in the epileptic temporal lobe several minutes before EEG seizure onset. Thus, rCBF changes observed on peri-ictal SPECT scan cannot be considered a mere consequence of EEG seizure activity but may rather reflect a change in neuronal activity precipitating the transition from the interictal to the ictal state.

Adult↗

PubMed1998

[Investigation of the brain reactiveness depending on the type of human intrinsically present electroencephalography].

While adopting the lighting flashes 9 Hz in frequency, and while the absence of the adopting the rythm reaction during the photostimulation conduction in majority of the patients examined the alpha-oscillations amplitude according to background electroencephalography constitutes 25-50 mcV; while adopting of the lighting flashes rythm with 6 and 12 Hz frequency--50-75mcV.

Adult↗

PubMed2006

Anticipatory electroencephalography alpha rhythm predicts subjective perception of pain intensity.

UNLABELLED: This high-resolution electroencephalography (EEG) study tested the hypothesis that the suppression of rolandic alpha power before predictable painful stimulation affects the subject's subsequent evaluation of pain intensity, as a reflection of the influence of expectancy processes on painful stimulus processing. High-resolution EEG data were recorded (126 channels) from 10 healthy adult volunteers during the expectancy of a painful CO(2)-laser stimulation at the right wrist. Surface laplacian estimation enhanced the EEG spatial information content over 6 scalp regions of interest (left frontal, right frontal, left central, right central, left parietal, and right parietal areas). Spectral power was computed for 3 alpha sub-bands with reference to the individual alpha frequency peak (about 5-7 Hz for alpha 1, 7-9 Hz for alpha 2, and 9-11 Hz for alpha 3). The suppression of the alpha power before the painful stimulation [as reflected by the event-related desynchronization (ERD)] indexed the anticipatory cortical processes. Results showed maximum (negative) correlations between the alpha 2 and alpha 3 ERD amplitude at the left central area and the subjective evaluation of pain intensity (P < .001). The stronger the anticipatory alpha 2 and alpha 3 ERD, the higher the subjective evaluation of pain intensity. For alpha 3, that correlation was confirmed even when the effect of habituation across the recording session was taken into account. These results suggest that the anticipatory suppression of the alpha rhythms over the contralateral primary sensorimotor cortex predicts subsequent subjects' evaluation of pain intensity, in line with its crucial role for the discrimination of that intensity. PERSPECTIVE: This electroencephalographic study showed that anticipatory activation/deactivation of sensorimotor cortex roughly predicts subjective evaluation of pain. This motivates further investigation on possible implications for the understanding of central chronic pain. Chronic pain patients might exaggerate the anticipatory activation of sensorimotor cortex to negligible pain stimuli.

Adult↗

PubMedDate not supplied

Reported chronic insomnia is independent of poor sleep as measured by electroencephalography.

OBJECTIVE: Several behavioral, physiological, and subjective variables were examined in subjects reporting chronic insomnia (IN group) and subjects with no complaint of insomnia (NC group) to determine factors predictive of poor sleep as measured by electroencephalography (EEG sleep). METHODS: A total of 177 subjects (121 in the IN group and 56 in the NC group) were evaluated on the basis of EEG sleep, subjective sleep, sleepiness, performance, mood, personality, and metabolic parameters during a 36-hour laboratory stay. RESULTS: Equal percentages of subjects in each group had 0, 1, or 2 nights of poor EEG sleep, indicating that the IN group was not more likely to have impaired sleep in the laboratory. Results of the Minnesota Multiphasic Personality Inventory showed that subjects in the IN group had more pathological personality profiles, and results of laboratory studies showed that these subjects had worse mood ratings, less subjective sleepiness, poorer memory performance, and longer midafternoon sleep latencies. Subjects in the IN group also rated their laboratory sleep as poorer in quality with more time awake after sleep onset and longer sleep latencies, but no differences in EEG sleep were observed. Poor nights of EEG sleep were associated with being male, increasing age, and a history of more time awake after sleep onset; among the laboratory tests, poor EEG sleep was associated with worse mood ratings, poorer memory performance, longer sleep latencies (as indicated by higher scores on the Multiple Sleep Latency Test), higher sleep/wake ratios for metabolic parameters, lower ratings of sleep quality, and longer perceived sleep latencies. CONCLUSIONS: A history of chronic insomnia does not predict poor EEG sleep. Both chronic insomnia and poor EEG sleep are associated independently with dysphoria, hyperarousal, diminished waking function, and negative subjective sleep quality. Separate arousal and sleep systems are posited to account for these results.

Adolescent↗

PubMed2002

Early and persistent impaired percent alpha variability on continuous electroencephalography monitoring as predictive of poor outcome after traumatic brain injury.

OBJECT: Early prediction of outcomes in patients after they suffer traumatic brain injury (TBI) is often nonspecific and based on initial imaging and clinical findings alone, without direct physiological testing. Improved outcome prediction is desirable for ethical, social, and financial reasons. The goal of this study was to determine the usefulness of continuous electroencephalography (EEG) monitoring in determining prognosis early after TBI, while the patient is in the intensive care unit. METHODS: The authors hypothesized that the reduced percentage of alpha variability (PAV) in continuous EEG tracings indicates a poor prognosis. Prospective continuous EEG monitoring was performed in 89 consecutive patients with moderate to severe TBI (Glasgow Coma Scale [GCS] Scores 3-12) from 0 to 10 days after injury. The PAV was calculated daily, and the time course and trends of the PAV were analyzed in comparison with the patient's Glasgow Outcome Scale (GOS) score at the time of discharge. In patients with GCS scores of 8 or lower, a PAV value of 0.1 or lower is highly predictive of a poor outcome or death (positive predictive value 86%). The determinant PAV value was obtained by Day 3 after injury. Persistent PAV values of 0.1 or lower over several days or worsening of the PAV to a value of 0.1 or lower indicated a high likelihood of poor outcome (GOS Scores 1 and 2). In comparison with the combination of traditional initial clinical indicators of outcome (GCS score, pupillary response to light, patient age, results of computerized tomography scanning, and early hypotension or hypoxemia), the early PAV value during the initial 3 days after injury independently improved prognostic ability (p < 0.01). CONCLUSIONS: Continuous EEG monitoring performed with particular attention paid to the PAV is a sensitive and specific method of prognosis that can indicate outcomes in patients with moderate to severe TBI within 3 days postinjury.

Adult↗

PubMed2001

Quantitative electroencephalography in Alzheimer's disease: comparison with a control group, population norms and mental status.

OBJECTIVE: Given that quantitative electroencephalography (EEG) has repeatedly shown excessive slow wave activity in dementia of the Alzheimer type (DAT) that increases with disease progression, we assessed the clinical utility of this tool by comparing various approaches used to assess slowing. DESIGN: Cross-sectional study comparing quantitative EEG data from patients with DAT with normative data from an elderly control group and from EEG norms derived from a large population. PARTICIPANTS: 35 subjects diagnosed with probable DAT and 30 elderly controls. OUTCOME MEASURE: EEG recorded from 21 scalp sites of each patient and elderly control during vigilance-controlled, eyes-closed, resting conditions was spectrally analyzed to yield measures of absolute and relative power in delta, theta, alpha and beta bands and indices of mean alpha band and total band frequency. RESULTS: Group comparisons of raw or age-regressed z-score population normative values yielded different profiles with respect to direction of frequency band changes, regional topography and clinical rating correlations, but both procedures evidenced overall patterns of EEG slowing in DAT. However, both methodologies yielded only modest (75%) classification rates. CONCLUSION: Quantitative EEG remains a valuable research tool but, as yet, an unproven diagnostic tool, for DAT.

Aged↗