Triphasic waves in a fully alert patient with liver disease.
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Alpha Rhythm↗
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Persistence of EEG activity with prolonged induced hyperthermic fever.
Ten instances of deliberate systemic temperature elevation in the 41.5 degrees C to 42.2 degrees C range have been evaluated electroencephalographically, demonstrating decrease in predominant frequency and voltage. Persistence of electro-cerebral activity suggests that previous reports of electro-cerebral inactivity with elevated temperatures reflect indirect serious effects due to cardiovascular compromise with cerebral ischemia, rather than to a direct temperature-related loss of CNS electrical activity.
Anesthesia, General↗
The Clinician Assessment of Fluctuation and the One Day Fluctuation Assessment Scale. Two methods to assess fluctuating confusion in dementia.
BACKGROUND: The identification of fluctuating confusion is central to improving the differential diagnosis of the common dementias. AIMS: To determine the value of two rating scales to measure fluctuating confusion. METHOD: The agreement between the clinician-rated scale and the scale completed by a non-clinician was determined. Correlations between the two scales were calculated; variability in attention was calculated on a computerised cognitive assessment and variability in delta rhythm on an electroencephalogram (EEG). RESULTS: The Clinician Assessment of Fluctuation and the computerised cognitive assessment were completed for 155 patients (61 Alzheimer's disease, 37 dementia with Lewy bodies, 22 vascular dementia, 35 elderly controls). A subgroup (n = 40) received a further evaluation using the One Day Fluctuation Assessment Scale and an EEG. The two scales correlated significantly with each other, and with the neuropsychological and electrophysiological measures of fluctuation. CONCLUSIONS: Both scales are useful instruments for the clinical assessment of fluctuation in dementia.
Aged↗
Automatic classification algorithms of the EEG monitor Narcotrend for routinely recorded EEG data from general anaesthesia: a validation study.
Impacts of hypnotic drugs on brain function are reflected in the EEG. The EEG monitor Narcotrend performs an automatic classification of the EEG using a scale which was proposed by Kugler for visual evaluation of the EEG. In this article the results of a validation study of the automatic classification algorithms implemented in the EEG monitor Narcotrend are presented. Visual and automatic classification of EEG data recorded in routine clinical practice were compared. The correlation between visual and automatic assessment was high (Spearman rank correlation r = 0.90, prediction probability Pk = 0.90) and a sufficient agreement between visual and automatic assessment was achieved for 92% of the analysed EEG epochs. The results of the study suggest that the automatic classification algorithms implemented in the EEG monitor Narcotrend yield a reliable assessment of the depth of hypnosis.
Algorithms↗
[Epileptic signs in alterations of neuronal migration].
INTRODUCTION: A wide range of conditions are due to alterations in neurone migration (ANM). Mental retardation, motor disorders and epilepsy are seen in all these disorders. Anomalies included with the ANM are those produced at the time of neuronal migration in the phase prior to neurone proliferation and during the time following cortical organization. All these have a common characteristic, namely an anomalous cerebral cortex (cerebral dysplasias). DEVELOPMENT: There is a high incidence of epilepsy in ANM (60%), appearing early (10% neonatal, 42% before 1 year old). The frequency of crises increases with age. Extended and diffused generalized forms presents as epileptic encephalopathies (Ohtahara, West, Lennox-Gastaut), whilst focal forms are seen as simple motor, partial crises, complex and secondarily generalized crises with a tendency to status epilepticus and also to continuous partial epilepsy. In diffuse, extensive forms, the EEG is characterized by large amplitude theta-delta rhythm activity (specific) with the presence of rapid activity (15-25 Hz) and of large amplitude (150-300 microV) which may also be found in other processes. In localized forms the recordings vary: localized discharges with/without crises, multifocal discharges in more than two lobes with a defined critical area, positive discharges, ipsilateral spike-and-wave complexes associated with focal discharges or with normal recordings. We review different types of ANM: in the phase of proliferation (hemimegalencephalia), the agyria-paquigyria complex; in phase of migration: type I lissencephalias (Miller-Dieker), layered heterotopias (double cortex), type II (cobblestone) lissencephalias and neuronal heterotopias, and in the phase of organization of the cortex: polymicrogyria and the esquissencephalias I and II. CONCLUSIONS: The functional prognosis in ANM depends on the control of the crises rather than on the extent of the lesion. Surgical treatment leads to 42% good or excellent results.
Brain↗
The effect of delta sleep-inducing peptide on the EEG and power spectra in rat.
The effects of delta sleep-inducing peptide (DSIP) on the EEG and power spectra of adult male Wistar rats (b.w. 180-220 g) were studied by power spectra analyses of EEG wave forms recorded continuously for 12 h after DSIP administration. The animals were given DSIP i.p. (1 mg/kg). Saline-injected rats served as the corresponding control. Recorded bursts of high amplitude EEG in the 1-9 Hz range (delta and theta) were found to be more frequent in DSIP-treated animals, while power spectra and (delta) wave activity were enhanced in comparison with the control and a statistically significant increase was registered in all experimental points after DSIP (2 h P < 0.05; 4 h P < 0.05; 5 h P < 0.05; 6 h P < 0.05; 7 h P < 0.01; 11 h P < 0.05). In addition, DSIP significantly elevated both the EEG output in the (delta) range and sleep activity. These results suggest that DSIP should be considered as a potential agent for the treatment of sleep disturbances in human medicine.
Animals↗
[Electroencephalographic studies in migraine].
The author reviews the pertinent literature and the results of own investigations in migraine. EEG changes in migraine are observed in nearly 50% of cases during attacks as well as in the periods free of pains. Most investigations were done in the periods between attacks. The H response characteristic of migraine was found by the author in 25% of cases only. Focal changes were present in 30% of cases. They were not related to the side of the pain, its duration and the form of migraine. Seizure activity was never observed. The author regards isolation of the so-called dysrhythmic form of migraine as not justified. EEG changes suggest--according to the author--that migraine is a primary cerebral and only secondarily a vascular disorder.
Alpha Rhythm↗
[Rhythmical processes in the cerebral cortex bioelectrical activity in arousal reaction: qualitative nonlinear analysis involving refractoriness].
An integral equation that takes into account the absolute and relative refractory periods of cortical cells was added to the earlier obtained integral equations describing the cooperation of excitatory and inhibitory neurons of the cerebral cortex, and its substantiation was suggested. The steady states and the stable region of oscillations of the mean membrane potential of excitatory neurons were investigated depending on the mean afferent influx value on the assumption of the normal threshold distribution of cells. The existence of a parameter multitude in the region of stability was shown when a suppression of the delta-rhythm and an enhancement of the theta-rhythm up to its dominance take place increasing nonspecific afferent influx, which shows up a white noise, and decrease of the theta-rhythm during further increase in nonspecific activation. Simultaneously the frequencies of the major cerebral rhythms increase. The conformity of the theoretically calculated dependences of changes of the spectrum upon increasing nonspecific afferent influx to the experimental data obtained during the electrical stimulation of the rabbit midbrain reticular formation was demonstrated.
Afferent Pathways↗
[Electrical activity of the caudate body during the orienting reaction in dogs].
It has been shown that during an orienting reaction a delta-rhythm sets in in the dog EEG of the caudate nucleus head, which coincides with facilitation of the recruited rhythm in the auditory cortex EEG and inhibition of the motor activity. It has been assumed that the caudate nucleus head is involved in the processes of limitation of non-selective movements during orienting reactions.
Animals↗
[Reflection of evolutionary trends in the recovery pattern of the electrical activity in the human brain after unilateral electroshock].
After unilateral electroshocks the following stages of the recovery of EEG may be defferentiated in man: residual seizure activity, flat EEG, low-amplitude polyform arrhythmia, monoform delta-rhythm, synchronized teta- and alpha-rhythms. It is assumed that changes of these stages reflect the migration of EEG pacemakers within the system of hierarchically interrelated brain structures, which provide for various forms of regulation of the electrical activity of the cortex. It was shown that in each of the hemispheres, pacemakers operate relatively independently and that electrical stimulation of the dominant (left) hemisphere affects brain activity to a greater extent than stimulation of nondominant (right) hemisphere. The ascending influences of desynchronizing systems of the brain stem are less lateral as compared to the ascending pathways of hypothalamic and thalamic structures.
Biological Evolution↗
[Neuronal activity in the nucleus basalis magnocellularis during performance of an instrumental task].
Spike activity of 95 neurons in the rabbit basal forebrain forebrain magnocellular nucleus was recorded during spontaneous behavior and instrumental conditioned performance. Almost half of the neurons (48.4%) displayed a significant (p > 0.05) negative correlation between their spontaneous discharge rate and the power of the delta rhythm in the EEG of the frontal cortex; most of these cells can be classified as projection cholinergic neurons. During instrumental conditioned performance, neurons of this subgroup responded with excitation to the conditioned stimulus, whereas presumably noncholinergic nonprojection neurons responded to the conditioned stimulus with inhibition. Excitatory response of cells in the basal forebrain magnocellular nucleus was significantly more intense as compared to trials without the conditioned reaction. On the whole, our data testify that the basal forebrain magnocellular nucleus maintains the level of arousal and attention required for the instrumental conditioned performance.
Acetylcholine↗
[Prognostic value of some spectral EEG indices in patients in acute period of brain supratentorial hemorrhagic stroke].
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Acute Disease↗
Electrocardiographical case. A case of wide complex tachycardia.
A 43-year-old Chinese woman complained of a one week history of irregular rapid palpitations associated with chest discomfort and dyspnoea. Her heart rate was more than 160 beats per minute and blood pressure was 154/95 mmHg. 12-lead electrocardiogram (ECG) showed a wide complex tachycardia with a slightly irregular rhythm. Delta waves were also present. She was treated appropriately with intravenous procainamide but developed torsades de pointes secondary to prolonged QT interval. Electrophysiology study revealed atrial tachycardia with a left-sided accessory pathway which was successfully ablated.
Adult↗
[Special features of age development of the brain in children living in the north].
Special features of morphological functional age development of the brain in children living in difficult climatic-geographical and social-economical conditions of the North (Archangelsk region) were studied. It was found that among 62 examined pupils of middle country school only in 10 persons (16%) amplitude-frequency and temporal-spatial EEG parameters are in accordance with passport age (European standards). 38 pupils (61%) have insignificant deviations such as insufficient regularity of EEG spatial-temporal pattern in frontal and temporal parts of the brain, increased theta- and delta-rhythms, absence of distinct "functional nuclear" in alpha range. In remaining 14 pupils (23%) EEG parameters suggest a more expressed retardation of mental development coupled with problems in the learning and inadequate behavior. Retardation of terms of morphological functional development of the brain in children--northerners equals 1.5 - 2 years, which is in accordance with terms of hormonal and physical development' retardation, described by different authors.
Adolescent↗
[The interhemispheric asymmetry of the spatial-temporal organization of cortical potentials in the rabbit].
In experiments on freely moving rabbits the existence of interhemispheric asymmetry of spatial-temporal organization of the cortical potentials in the state of calm alertness was shown. Episodes were revealed of interhemispheric discordance of spatial reconstructions of momentary reliefs of the cortical potentials topograms 1/64-1/3-1/5 s in duration, i.e. periods of the theta- or delta-rhythms. Total duration of time of interhemispheric asymmetry (according to significant divergences in dynamics of resemblance coefficients of consequent reliefs of the cortical potentials topograms) in most cases was not less than 10% and not more than 30% of time of analysis epoch and consisted of discordance episodes both of different global reconstructions of spatial correlations of the left and right hemisphere potentials and of interhemispheric local shifts in spatial organization of the cortex potentials.
Animals↗
The effect of GRF on the EEG sleep of normal males.
The administration of GRF in young men either before sleep onset or coinciding with sleep onset leads to an immediate significant increase in GH secretion. These increases were not associated with major alterations in sleep including slow-wave sleep.
Adult↗
[Pharmacological investigations of 4'-fluoro-4-(4-methyl-peperidono)-butyrophenone with respect to its sedative and sleep-inducing properties (author's transl)].
The butyrophenone melperone (Eunerpan) in mice and rats caused a prominetn inhibition of spontaneous activity, whereas cataleptogenic and apomorphine-antagonistic properties were less pronounced. In rats the sleep-cycle was altered: decrease of wakefulness, increase of slow-wave sleep and a moderate reduction of rapid eye movement-(REM) sleep. In contrast to thioridazine and chlorpromazine the effect lasted only for 4 h, followed by a slight REM rebound. In rabbits melperone caused a decrease of muscle tone and with somewhat higher doses an inhibition of the arousal-reaction. As seen by the computerized spontaneous cortical EEG, dosages below 1 mg/kg caused a shift of the dominant frequency from theta- to delta-rhythm and an increase of power. Therefore the neuropharmacological pattern of the butyrophenone melperone is closely related to those of thioridazine or chlorpromazine, without, however, having their long action.
Animals↗
[Studies of sleep in affective disturbances].
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Affective Symptoms↗