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Results for “Delta Rhythm”

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At least 127 records · Page 7Linked to original sources
PubMed1991

[Intraoperative computed EEG monitoring for evaluating the adequacy of general anesthesia].

The article analyses the possibilities of computed EEG monitoring for evaluation of the magnitude and adequacy of the modern methods of general anesthesia: NLA, NLA with halothane inhalation, NLA including Kalipsol bolus administration. An original coefficient, called the adequacy index (AI), was found, which reflects the percentage contribution of deep rhythms (delta and theta) to the total power of the EEG in the range of 0 to 20 Hz. It is shown that the dynamics of this index correlates with the degree of the blocking of entry of sensory nociceptive information into the CNS. The lower boundary of AI-70% was determined, below which the generally accepted signs of anesthesia inadequacy appear: hyperactivity develops, a shift of pH in the acid direction occurs, and the base deficiency increases. It is suggested that determination of AI is used as a highly sensitive and operative test for routine monitoring of the patient's intraoperative condition and express diagnosis of inefficacy of anesthesia.

Anesthesia, General↗
PubMedDate not supplied

[EEG studies in Alzheimer dementia and multi-infarct dementia at various times of the day].

From three men and seven women (mean age 70 years) with dementia of the Alzheimer-type (DAT), and from four men and six women (mean age 77 years) with multi-infarct dementia (MID) closed-eye EEGs were registered at 0800, 1200, 1600, and 2000 hours and recorded on tape for computer processing. The data of both groups were compared statistically and also compared with data of former investigations conducted with 10 healthy elderly volunteers and 10 patients who suffered from cerebral arteriosclerosis with serious disorder of sleep-walking rhythm (HA). Most pathological EEG deviations are found in the MID-patients, but there is no significant distinction compared to the DAT-patients, although three of the latter showed normal EEGs. Compared to the HA the EEGs of the MID-patients differed more from those of the healthy volunteers; however, the physiological circadian variations were not leveled as in the HA. Even in consideration of daytime dependent fluctuations of frequency-parameters, a clear-cut discrimination between DAT and MID by means of the EEG seems impossible.

Aged↗
PubMed1989

[Effects of huperzine A on electroencephalography power spectrum in rabbits].

Huperzine A (Hup-A) is a new alkaloid extracted from Huperzia serata in China. The effects of Hup-A on learning and memory are superior to those of physostigmine (Phys). The purpose of this paper is to observe the effects of Hup-A on EEG and EEG power spectrum in rabbits with micro-computer analysis. Hup-A 0.1 mg/kg iv in conscious rabbits produced, after 0.5 min, an alert EEG pattern, which showed decreases of lower frequency components and the total EEG power in cortical area, and the dominant frequency transferred from delta rhythm to theta rhythm in hippocampus. The same effects were seen with Phys 0.1 mg/kg. Scopolamine (Scop, 0.2 mg/kg iv) reversed significantly these effects of Hup-A (10 micrograms/rabbit, icv), but Scop butylbromide (0.4 mg/kg, iv) which can not pass the blood-brain barrier did not. Hup-A 0.2 mg/kg iv or Phys 0.3 mg/kg iv antagonized the EEG effects of Scop 0.3 mg/kg iv. The results indicate that the effects of Hup-A are closely related to the action on the central cholinergic system.

Alkaloids↗
PubMedDate not supplied

[Changes in EEG rhythms during verbal and visual-image thinking].

General and local characteristics of EEG activation were studied in frontal, central, temporal and occipital areas of the left and right cerebral hemispheres in 20 adult subjects during execution of various mental tasks. The analysis of the changes of five main EEG rhythms (delta, theta, alpha, beta-1 and beta-2) showed that EEG power decrease in alpha- and beta-frequency ranges is a reliable and sensitive index of brain activation at thinking. On this basis EEG activation mosaics are described at carrying out of each task and its systemic changes at transition from one type of task to another one, depending on their psychological structure--modality and complexity.

Adolescent↗
PubMed1988

Transient global amnesia after mild head injury in childhood.

In seven entirely healthy children in the age group of 6.5 to 14.5 years, mild head injury produced transient global amnesia (TGA) of median duration of 4.5 hours. None of the patients had convincing signs of brain concussion or clinical focal symptomatology. In four cases CT examination of the brain showed normal findings. Four children had a transient abnormal EEG (intermittent delta rhythms, slowed background activity inconstant local finding (of slow waves). During the period monitored (2-34 months) there was no recurrent attack and the children have had no difficulties. Pathologically, the authors assume ischemia of temporobasal structures induced by mild trauma with a relationship to migraine diathesis and rank the child group among so called benign posttraumatic encephalopathy with a noncomplicated course and good outcome.

Adolescent↗
PubMed1985

[Are subcortical signs in the EEG a reliable indication of brain stem displacement and impaction processes by intracranial space-occupying processes? A comparative computer tomography-electroencephalography study].

Within the scope of an elektroencephalographic-computertomographic comperative study carried out in 430 patients, the concurrence of secondary brain stem damage due to mass displacement and herniation processes and parroxysmal generalised slow activity in the EEG ("intermittant frontal delta rhythms", "projected discharges", "subcortical signs") in intracranial space-occupying processes were studied among others. The occurrence of the EEG pattern was independent of the presence of brain stem displacements in about 20 and 25 per cent, respectively, of the 152 patients with supratentorial space occupations. The absence of the characteristics on 80 per cent of the patients with clear CT criteria for a secondary brain stem impairment shows that it is not suitable as a warning sign of an imminent intracranial decompensation and that in particular from the non-occurrence in the EEG no contribution to the operative risk and to the choice of the time of the operation can be derived. A relation between the occurrence of paroxysmal slow activity and the acuity of the course of the disease or the degree of malignity of cerebral tumours could not be verified. Possible causes of the inconstant occurrence of this EEG pattern in brain stem alterations are discussed.

Adolescent↗
PubMed1984

[Correlation between EEG and auditory brainstem response (ABR) in comatose patients--diagnosis of brain death by ABR].

ABRs and EEGs were recorded from fifty comatose patients. Among them 21 patients were in deep coma and remaining 29 were in brain death that was diagnosed from clinical criteria. All the patients who showed some activity in EEG had ABR which showed waves I through V. However, there was no correlation between grade of EEG classification, dominant alpha, theta, or delta rhythm, and the inter wave latencies between waves I through V in the ABRs. Eleven of the twenty-nine patients who were diagnosed as brain death from clinical criteria and isoelectric EEG showed waves I through V potentials in ABR. Eight of these eleven patients even exhibited normal or nearly normal ABRs which had I to V latencies less than 4.4 ms. However, all the patients who showed isoelectric EEG and no response ABR died. Thus it is concluded that the ABR should be included for identification of brain death in addition to the clinical examination and EEG recordings.

Brain Death↗
PubMedDate not supplied

[Hypnogenic properties of the delta-sleep peptide and its structural analogs].

It has been demonstrated in unrestrained rabbits that the delta-sleep-inducing peptide (DSIP, 60 micrograms, intraventricularly) produced sleep lasting 55-65 min. At that time the amount of delta-waves on the EEG was 230 % of the initial level. Of the 22 structural analogs of DSIP, the DPhe-containing compound compared favourably with the delta-sleep-inducing peptide as regards the activity. Other analogs were either less active or had no hypnogenic activity at all.

Animals↗
PubMed1983

[Effect of delta-sleep-inducing peptide and its analogs on the encephalogram of normal rabbits during sleep deprivation and on learning processes in the rat].

The delta-sleep-inducing peptide and its 10 analogues increased the total amount of slow oscillations in the rabbit EEG and shifted the spectrum towards the long-wave area. When comparing the EEGs of intact and sleep--deprived rats, the effect of delta-peptide was stronger in the latter animals. The learning of rats in U-shaped labyrinth before and after sleep deprivation suggested that delta-peptide improved the learning in sleep-deprived animals. Experiments with negative influences showed that the delta-peptide could be a protective anti-stress factor.

Animals↗
PubMed1982

[Intracerebral fibrous xanthosarcoma--report of a case].

A 61-year-old and right handed man was admitted to our department on August 11, 1980. The patient had three month history of focal fits, progressive hemiplegia, and motor dominant aphasia. The neuroradiological examination revealed a space taking lesion at the left frontoparietal area, which showed a small tumor stain with early filled draining vein on the left carotid angiogram, and iso-high dense mass with marked contrast enhancement on the CT scan. The EEG findings showed polymorphous delta rhythm in the left frontal and parietal areas. On August 28, total removal of the tumor was performed. The tumor was a intracerebral, fibrous cystic mass without involvement of the pia and dura mater. The removed tumor was measured approximately 6 X 5 X 4 cm in size, and consistence of the tumor was mostly elastic hard and partially soft and hemorrhagic. Histologically, the tumor composed of an admixture of bizarre histiocytes and fibroblasts, multinucleated giant cells, xanthoma cells and siderophages, with fibrous stroma. After surgery, no distinct lesion was demonstrated on the whole body CT scan and garium and technetium scintigram in the abdomen and the lung. The right hemiplegia and aphasia were improved gradually, and the patient discharged on December 20, 1980. We discussed the origin of this tumor, and angiographic and CT scan findings on the literature.

Brain Neoplasms↗
PubMedDate not supplied

A signal analysis approach to rat sleep scoring instrumentation.

Automated rat sleep analysis focuses on the statistically regular waveforms of the EEG, such as theta and delta rhythms. Such stochastic processes can be quantified in several manners. Time domain statistics such as auto- and cross-correlations produce outputs that are difficult to use and are best performed in software. Frequency domain statistics like spectral density accurately quantify the sleep state by power-frequency distributions but also require sophisticated computer processing. Continuous frequency analysis, using pass-band filtering, accurately measures signal power in an on-line fashion and employs relatively inexpensive hardware to estimate power by integrating the square of the signal. This method differs substantively from other previously reported systems which rely on signal amplitude analysis. Comparison of this system with a human scorer indicates high degrees of validity and reproducibility.

Animals↗
PubMed1979

[Course of ether anesthesia and the post-anesthesia period against a background of prior vibration].

The experiment on albino rats showed that three-hour vibration (46.6 Hz, 1mm amplitude) decreases the functional activity of the central nervous system as well as that of the respiratory and circulatory apparatus. Ether anesthesia against this background aggravates the animals condition and they die during the post-anesthesia period (60% of cases). Survival of the animals under conditions of extreme actions (vibration, anesthesia) is estimated by the cerebral cortex resistance level.

Alpha Rhythm↗
PubMed1994

[Night sleep in temporal-lobe epilepsy in children].

Polygraphy of night sleep performed in 31 children with temporal epilepsy showed enhanced nonspecific mesolimbic activation, probably of compensatory nature, in patients with common partial fits or complex partial fits. In wakeful patients with complex partial fits there were signs of growing influence of synchronizing inactivating non-specific structures.

Adolescent↗
PubMedDate not supplied

[The importance of electroencephalographic studies for evaluating the action of physical treatment methods in patients with a neuroendocrine syndrome and disordered menstrual function].

Electroencephalograms of 43 females (mean age 27.3 +/- 5.2 years) were examined for integral power of various EEG rhythms, delta, beta, alpha, beta 1 intervals for occipital, parietal and frontal region, right and left hemispheres. The frequency analysis was made with regard of EEG type. A particular role of the right hemisphere in development of neuroendocrine pathology is discussed.

Adult↗
PubMed1996

Evidence that GABA, serotonin, and norepinephrine are involved in the modulation of in vitro rhythmical activity in rat hippocampal slices.

Cholinergic agonists induce a rhythmical slow activity (RSA) in the in vitro rat hippocampus. RSA consists of bursts of activity separated by quiescent periods (interburst intervals). The activity involves activation of muscarinic receptors; however, the role of other neurotransmitter substances is still controversial. The present study demonstrates that 500 microM GABA, 15 microM serotonin (5HT), or 20 microM norepinephrine (NE) can alter the pattern of carbachol-induced RSA. Application of GABA, 5HT, or NE increases interburst interval; 5HT and NE also increase burst length. Total power of RSA is decreased by GABA and 5HT but increased by NE. None of the three receptor agonists alters RSA frequency. The pattern of RSA is also dependent upon carbachol concentration: low concentrations (0.5 and 1 microM) produce only population spikes, whereas concentrations of 3 to 100 microM produce burst activity (50 microM is optimal for the generation of RSA). Burst length and peak frequency of RSA are enhanced with increasing concentrations of carbachol, whereas interburst interval is decreased. The results illustrate that the pattern of RSA is not only dependent upon carbachol concentration but can be modulated by GABA, 5HT, and NE. This suggests that more than one neurotransmitter system contributes to the production and modulation of RSA.

Alpha Rhythm↗