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PubMed1993

Genetic profiles of morphine-induced EEG, EEG power spectra, and behavior in two inbred rat strains.

The purpose of the present study was to examine and compare the effects of morphine at doses of 3, 10, and 30 mg/kg, IV, on EEG, EEG power spectra, and behavior in two inbred rat strains, Lewis and Fischer 344. Duration of morphine-induced EEG slow-wave bursts and associated behavioral stupor was greater in Lewis rats. Latency to slow-wave sleep increased in a dose-related manner for both strains; differences were not significant between the two groups. The analog EEG signal was transformed by fast Fourier analysis; six power spectral quantities were examined: peak frequency, complexity, mobility, mean frequency, edge frequency, and total power. With the exception of peak frequency and edge frequency, all differed as a function of inbred rat strain. Regarding morphine dose, all spectral parameters differed except peak frequency. Factor analysis on morphine-induced EEG revealed a unique factor for each strain that was bipolar in nature and may be associated with the burst and interburst periods that occur in EEG after opiate administration. Genetic variability appears to play a role in the behavioral, EEG, and derived power spectral responses of both LEW and F344 inbred rat strains following acute morphine administration. These results may reflect differences in neurosensitivity and/or opioid receptor populations between Lewis and Fischer 344 inbred rat strains.

Animals↗
PubMed2004

Frequency of EEG abnormalities in age-matched siblings of autistic children with abnormal sleep EEG patterns.

Epileptiform activity in sleep has been described even in the absence of clinical seizures in 43-68% of patients with autistic spectrum disorders (ASDs). Genetic factors may play a significant role in the frequency of epilepsy, yet the frequency in normal age-matched controls is unknown. We studied overnight ambulatory electroencephalograms (EEGs) in 12 nonepileptic, nonautistic children with a sibling with both ASDs and an abnormal EEG. EEG studies were read and described independently by two pediatric epileptologists; 10 were normal studies and 2 were abnormal. The occurrence of abnormal EEGs in our sample (16.6%) was lower than the reported occurrence in children with ASDs. Further, the two abnormal EEGs were of types typically found in childhood and were different from those found in the ASD-affected siblings. The lack of similarity between sibling EEGs suggests that genetic factors alone do not explain the higher frequency of EEG abnormalities reported in ASDs.

Autistic Disorder↗
PubMed1981

Spectral analysis of EEG in the late course of primary generalized myoclonic-astatic epilepsy. I. EEG and clinical data.

The EEG of 38 patients suffering from primary generalized myoclonic astatic epilepsy since early childhood is studied in late stages of the disease. Spectral analysis shows that parietal 4-7 cps rhythms (theta rhythms) which are typical of the EEG in the early stages of the disorder can still exist in the EEG of the adult. The rhythms seem to be related to the course of the epilepsy. In the EEG of patients who still have seizures rhythms occur more often than in the EEG of patients who are free of seizures in the two years before the reexamination of their EEG. The functional anomaly producing a 4-7 cps rhythmization of the parietal EEG seems to be one pathogenetic factor in some epileptic disorders of early childhood, especially in primary generalized myoclonic-astatic epilepsy.

Adolescent↗
PubMed2003

Very slow EEG responses lateralize temporal lobe seizures: an evaluation of non-invasive DC-EEG.

BACKGROUND: This study tested the idea that very slow EEG responses (direct current [DC] potential shifts) could be detected noninvasively during temporal lobe (TL) seizures, and that these shifts give lateralizing information consistent with that obtained by other methods. METHODS: Seven patients with TL epilepsy (TLE) were recorded with scalp DC-EEG technique at bedside. All recordings were performed simultaneously with conventional EEG (scalp in five, and intracranially in two; two patients with scalp recordings were recorded intracranially later). Seizures in five patients originated in the mesial TL. Ictal DC shifts were evaluated by comparing them to the temporal evolution of ictal discharges, and by comparing the laterality of these shifts to the side of seizure onset defined by routine EEG and other presurgical diagnostic tests. RESULTS: All seizures (35/35) were associated with negative DC shifts at temporal derivations (30 to 150 micro V relative to vertex), beginning at the electrical seizure onset, and lasting for the whole seizure. In eight seizures (five patients) with documented mesial TL onset, the polarity of the DC shift was initially positive followed by a negative one after lateral spread of seizure activity. In all cases, the side of the EEG shift agreed with other diagnostic tests, and, at times, was more clearly lateralized than the conventional scalp EEG. CONCLUSIONS: DC-EEG recordings are practical and achievable at the bedside. Ictal DC shifts are consistently observed in scalp recordings in TL seizures, and reliably lateralize them. This method may hold promise in reducing the need for invasive monitoring in patients with TLE where other noninvasive tests are equivocal.

Adult↗
PubMed2005

Clinical and EEG features of patients with EEG wicket rhythms misdiagnosed with epilepsy.

BACKGROUND: EEG wicket rhythms are 6- to 11-Hz medium-to-high voltage bursts that are sometimes misidentified as epileptogenic activity. The authors determined the clinical and EEG features of patients with wicket rhythms who had been incorrectly diagnosed with epilepsy. METHODS: Electroencephalographers at an epilepsy center re-read EEGs for patients referred for epilepsy management and identified patients with wicket rhythms. On further evaluation, the majority (54%; 25/46) of these patients were found not to have epilepsy. The authors compared the clinical and EEG features for the 25 patients with wickets and nonepileptic episodes with those of age- and sex-matched patients with partial-onset epilepsy using univariate and multivariate analysis. RESULTS: Several features distinguished patients with EEG wicket patterns and nonepileptic episodes (n = 25) from age- and sex-matched patients with epilepsy (n = 25): mid-adult age at onset of episodes (mean 38.4 years vs 19.8 years), prolonged clinical episodes (mean 155 minutes vs 2.3 minutes), and long duration of EEG wicket patterns (mean 0.66 seconds vs 0.11 second spikes). After controlling for other factors, patients without major confusion during episodes were unlikely to have epilepsy. CONCLUSION: Wicket patterns are often interpreted as epileptogenic. This distinctive EEG pattern should be considered in patients with clinical episodes atypical for epilepsy.

Adolescent↗
PubMed1987

Topographic brain mapping of EEG in neuropsychopharmacology--Part II. Clinical applications (pharmaco EEG imaging).

Multi-lead analysis of drug-induced changes in human brain function as monitored by the scalp-recorded electroencephalogram (EEG) and subsequent imaging of topographic pharmaco-EEG maps has become possible and practical with the advent of modern mini- and micro-computers. The present paper gives a survey about topographic analyses of pharmaco-EEG data obtained in systematic double-blind, placebo-controlled studies in normal healthy volunteers involving representative drugs of 5 different psychopharmacological classes, such as neuroleptics (chlorprothixene), antidepressants (imipramine), tranquilizers (diazepam), psychostimulants (caffeine), and antihypoxidotics/nootropics (pyritinol). The determination of cerebral bioavailability utilizing time- and dose-efficacy relations, as well as the evaluation of bioequipotency of different formulations of compounds is shown. Topographic pharmaco-EEG seems not only to confirm our previous knowledge that quantitative analysis of the human EEG in combination with certain statistical procedures ("quantitative pharmaco-EEG") is a valuable method to determine if, how, when and at which dosage a drug will be centrally effective, but also to have the potential to show effects of psychotropic drugs on the target organ--the human brain--which could not be previously picked up by single lead recordings. Topographic pharmaco-EEG imaging can be viewed as an enlargement of our armamentarium to better understand the mode of action of psychotropic drugs in human neuropsychopharmacology, as well as to monitor and (eventually) predict therapeutic efficacy in patients.

Adult↗
PubMed2005

[Neurofeedback-based EEG alpha and EEG beta training. Effectiveness in patients with chronically decompensated tinnitus].

BACKGROUND: Persisting tinnitus is an often devastating disease condition with restricted and rarely successful therapeutic options. PATIENTS AND METHODS: The present study investigates the therapeutic effect of short term neurofeedback-based EEG-Alpha- and EEG-Beta-training in 40 patients suffering from "chronic decompensated tinnitus". Patients were assigned to the Alpha or Beta group according to results of an initial EEG monitored stress-test. Four patients were excluded because they showed abnormal reactions in both EEG patterns. RESULTS: During 12 sessions, 23 patients succeeded to increase EEG Alpha activity by 16% (p< or =0.042) while 13 patients achieved no decrease of EEG Beta activity. However, both groups showed a significant reduction of subjective tinnitus annoyance by the end of the therapy (p< or =0.001) CONCLUSIONS: The results indicate that neurofeedback may represent a new promising technique in the therapy of chronic decompensated tinnitus. However, it remains to be established whether the reduction of tinnitus annoyance results from the altered brain activity patterns supported by the neurofeedback learning process.

Adult↗
PubMed1999

Visual stimulation elicits locked and induced gamma oscillations in monkey intracortical- and EEG-potentials, but not in human EEG.

Stimulus-related fast oscillations in the gamma-range (30-100 Hz) were clearly demonstrated with microelectrode recordings in visual cortex of awake monkeys, and they were also reported for recordings of human electroencephalograms (EEG). However, the presence of stimulus-related gamma-modulation in human EEG has repeatedly been disputed. To clarify this dispute, we recorded the scalp EEG of man and monkey as well as intracortical field potentials (LFP) from monkey primary visual cortex (V1) during identical visual stimulation (large-field sinusoidal gratings, which proved to induce the largest gamma-amplitudes in monkey V1 and V2). We found a strong stimulus-related increase of gamma-oscillations in monkey LFP and EEG, but no modulation of gamma-activity in human EEG. In contrast to previous results, gamma-oscillations in the monkey were strongly phase-locked to stimulus onsets in early response periods (80-160 ms) and became gradually independent in later periods. Our negative result on gamma-modulation in human subjects contradicts several published findings. We conclude from our results that visually evoked gamma-modulations in humans EEG are not as accessible as in the monkey.

Animals↗
PubMed1979

Hippocampal EEG and behaviour in dog. I. Hippocampal EEG correlates of gross motor behaviour.

It was shown that rewarding spectral shifts (i.e. increase in amplitude or peak frequency of the hippocampal EEG) causes a solitary dog to show increased motor behaviour. Rewarded spectral shifts concurred with a variety of behavioural transitions. It was found that statistically significant modulations occur in the spectral properties of the hippocampal EEG correlated with: (1) the transition from walking to standing; (2) the transition from standing while eating to walking away from the food dish; (3) the increase in speed of a walking dog, caused by rewarding the animal; and with (4) each head movement in a learned series of head movements. Thus behavioural transitions to a more active state are accompanied by an increase of amplitude, frequency and rhythmicity in the theta band of the hippocampal EEG; behavioural transitions to a less active state show the inverse relationship with the hippocampal EEG. A close relationship between modulations of the dog's hippocampal EEG activity and elementary motor acts is stressed. The hypothesis is put forward that the spectral properties of the hippocampal EEG reflect the degree to which a number of motor and sensory structures in the limbic midbrain and brain stem are active.

Animals↗
PubMed1982

Effects of acute delta 9-THC administration on EEG and EEG power spectra in the rat.

This study was designed to determine the acute effects of delta 9-THC on the cortical EEG with the spectral analysis technique. Adult female Sprague-Dawley rats were implanted with chronic cortical and temporalis muscle electrodes. Intraperitoneally administered delta 9-THC (5 and 10 mg/kg) produced a reduction in peak-to-peak voltage of the desynchronized cortical EEG during wakefulness. Associated spectral power was reduced to about 50% of control during the first hour after injection of delta 9-THC and gradually returned toward the control value over an 8-hr period. Occurrences of delta 9-THC-induced high-voltage EEG bursts, overriding the reduced EEG tracing, were associated with an EEG spectral peak at 6 Hz. The first few slow-wave sleep (SWS) episodes appearing after delta 9-THC administration were associated with more slow-frequency waveforms and more slow-frequency spectral power than with control slow-wave sleep episodes. During control rapid eye movement (REM) sleep episodes, an EEG theta wave pattern, with an associated spectral peak at about 8 Hz, was characteristic. Conversely, the first few REM sleep episodes emerging after delta 9-THC administration contained overriding high-voltage bursts, the related power spectra of which had two peaks at about 7 and 11 Hz.

Animals↗
PubMed1997

Dysmature EEG pattern in EEGs of preterm infants with cognitive impairment: maturation arrest caused by prolonged mild CNS depression.

The significance of mild sustained brain injury in the pathogenesis of perinatal brain damage was investigated using serial EEG recordings performed on 102 early preterm infants surviving beyond 2 years of age. Sixteen infants (16%) elicited mild depression of background EEG activities in the neonatal period. Of nine infants with mild depression of prolonged duration (more than 3 weeks), five (56%) were diagnosed as having cognitive impairment in the follow up study. Four showed no signs of cerebral palsy, while one had cerebral palsy. The infants with cognitive impairment showed mild prolonged depressions in background EEG activities in the early neonatal period and dysmature EEG patterns in the late neonatal period. They also showed maturation arrest in EEG patterns during prolonged mild depression of background EEG activities. In addition to strong sudden depression of CNS causing deep white matter injury and motor impairment, prolonged mild depression is another mode of brain injury in early preterm infants which can induce future cognitive impairment.

Brain Ischemia↗
PubMed2002

The sleep EEG's microstructure in depression: alterations of the phase relations between EEG rhythms during REM and NREM sleep.

OBJECTIVE: We investigated the microstructure of sleep electroencephalograms (EEGs) of 13 unmedicated depressive inpatients and 13 healthy controls matched in sex and age, hypothesizing that depressives depict an alteration of certain EEG oscillations across the night. METHODS: We digitized the sleep EEGs with a sampling rate of 100 Hz (bipolar derivation C(z)-P(z), 1440 single sweeps; 2048 data points each), calculated the time course of delta (1-3.5 Hz), theta (3.5-7.5 Hz), alpha (7.5-15 Hz), and beta (15-35 Hz) activity over the night, and determined the correlation coefficients of these different EEG rhythms separately for rapid eye movement (REM) and non-rapid eye movement (NREM) sleep. RESULTS: For both groups we detected a clear difference between REM and NREM sleep cycles at certain frequency bands. The most impressive changes occurred for the delta/beta and theta/beta correlations, which change their signs between NREM (negatively correlated) and REM (positively correlated) sleep cycles. Following an analysis of variance model with repeated measurement design, a statistically significant group effect (P=0.024) between depressives and controls was observable during NREM sleep for the delta/beta (P=0.010) and theta/beta (P=0.018) interactions. CONCLUSION: We detected alterations of certain sleep EEG oscillations during the NREM sleep cycle, where the delta/beta as well as the theta/beta activities were higher (negatively) compared to healthy controls. Together with previous investigations on the influence of antidepressants on the microstructure of sleep EEGs, this is another hint that the NREM sleep cycle plays a major role in depression.

Journal Article↗
PubMed1993

EEGs in phenylketonuria. I: Follow-up to adulthood; II: Short-term diet-related changes in EEGs and cognitive function.

The authors report the results of two EEG studies on adult patients with phenylketonuria (PKU) who had been treated early. Part I: the authors followed the EEGs of 34 PKU patients from birth to age 21. The frequency of abnormal EEG findings (especially epileptiform activity) steadily increased until age 12, then decreased. IQ correlated significantly with quality of dietary control during follow-up. Part II: frequency analysis of the EEG and neuropsychological testing were performed on eight adult patients after periods of four weeks with low and high levels of phenylalanine. Only five patients followed the strict dietary regulations. With high levels of phenylalanine, the dominant peak of EEG background activity shifted to the slower frequency spectrum in all patients; in addition, neuropsychological testing revealed impairment of cognitive function. The significance of different approaches of EEG examinations is discussed with respect to the problems of monitoring PKU patients and the pathogenic mechanisms of CNS damage in phenylketonuria.

Adolescent↗
PubMed1998

Ictal behaviors during nonepileptic seizures differ in patients with temporal lobe interictal epileptiform EEG activity and patients without interictal epileptiform EEG abnormalities.

PURPOSE: Ictal behaviors during psychogenic nonepileptic seizures (NES) vary considerably among individuals, and can closely resemble common semiologies of epileptic seizures (ES). We tested the hypothesis that behaviors during NES in patients who have temporal spikes would more closely resemble behaviors during ES in patients with temporal lobe epilepsy than would behaviors during NES in patients who do not have EEG spikes. METHODS: We identified 20 patients who had interictal temporal EEG spikes and EEG-video recorded NES (Study Group), 133 patients with temporal EEG spikes and recorded ES, without NES (Epileptic Group), and 24 patients with recorded NES and no epileptiform EEG abnormalities, without ES (Nonepileptic Group). RESULTS: The hypothesis was supported with regard to ictal motor behaviors. Motionless staring or complex automatisms occurred mainly during NES in the Study Group and during ES in the Epileptic Group. In contrast, convulsive movements or flaccid falls were most common during NES in the Nonepileptic Group. Duration of unresponsiveness was longer, and there were fewer postictal states in NES both in the Study and Nonepileptic Groups. Unresponsiveness was briefer and postictal states were more consistent in ES in the Epileptic Group, however. CONCLUSIONS: Stereotyped motor activities during NES presumably represent learned behaviors. Processes underlying acquisition of ictal behaviors of NES probably differ in patients with interictal epileptiform EEG abnormalities compared to those without. Prior experiences and temporal lobe dysfunctions that are associated with epilepsy, and psychological characteristics that are unrelated to interictal epileptic dysfunctions, may determine ictal behaviors during NES.

Adult↗
PubMed1987

EEG fitting: a new method for numerical analysis of EEG.

A new method for numerical analysis of EEG is described. It consists of fitting the EEG with orthogonal polynomials in several steps to separate the different frequencies contained in the original recording (high-frequency noise, beta, sigma, alpha, theta, delta, low-frequency noise). The original EEG is separated into 5 different signals with cutoff frequencies at 40, 18, 4 and 0.6 Hz. The activity in these signals is classified into the usual EEG bands by zero-crossing. The results are given as integrated values over 1 s in the different EEG bands, or wave by wave, each wave being described by its time of occurrence, amplitude and duration. This method is designed for accurate amplitude measurement in the frequency bands of EEG, particularly for application in psychiatry and psychophysiology.

Arousal↗