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Results for “Delta Rhythm”

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At least 19 recordsLinked to original sources
PubMed1979

System for studying the delta rhythm during sleep and its topographical amplitude distribution.

An analogue system of processing all-night sleep EEG records which leads to the representation of sleep cycles by the continuous variation of the amplitude parameter in a given frequency band is described. The curves obtained are analogous to those resulting from more sophisticated computerized analyses. The cycles which they outline are in good concordance with those of the classic hypnogram. Moreover, the simplicity and the rapidity of the processing easily allow its application to multiple EEG channels. A topographical discrimination of the amplitude parameter during sleep was observed in normal subjecttion. The results obtained are illustrated in the case of a normal child and a young normal adult.

Adult↗
PubMed1979

[The 4 c/sec rhythm (case report and differential diagnosis) (author's transl)].

Report on a female patient with a 3 c/sec rhythm. The 3 c/sec rhythm is a special case of the 4 +/- 1 c/sec rhythm. The characteristics of this variant are reviewed in tabulated form. The differential diagnosis has to take into consideration other slow posterior rhythms like the so-called delta-parenrhythmia and delta-parenrhythmia, abortive forms of spike and wave complexes and the abnormal delta-rhythms and sinusoidal delta-rhythms in the infantile EEG.

Adult↗
PubMed1992

Digital period analysis of sleep EEG in depression.

The period-analyzed sleep electroencephalogram (EEG) was compared in a group of 9 depressed outpatients and 9 age-matched normal controls. Both groups showed rhythms in beta, delta, and theta activity with an approximately 90-min period. The phase and coherence between fast and slow frequency EEG measures, however, differed significantly in the two groups. Beta and delta rhythms were less coherent in the depressed outpatient sample. The control group showed higher coherence and a strong coupling of beta and delta activity. These preliminary data suggest that depression may be associated with some degree of ultradian rhythm disturbances though periodicity is unaffected.

Activity Cycles↗
PubMed1991

The effect of exposure to impulse X rays on normal and epileptic activity in rabbit brain.

Exposure to X rays (20 impulses of 4 Hz frequency, total dose 0.6-1.1 mGy) increased the epileptic activity of a focal area, which was produced in the visual cortex of rabbit brain by freezing with liquid nitrogen, and by stimulating with flashes of light at frequencies of 5-6 Hz. The number of seizure complexes during photostimulation for 5 s increased by 80% compared with the initial level, and this effect continued for 15 min. In control animals (with no epileptic foci), a decrease was observed in the main frequencies of the delta rhythm and the theta rhythm (by 90% and by 10%, respectively) over the cortex as a whole. In rabbits with experimental epilepsy, the delta rhythm decreased only in the frontal lobes and in the lateral geniculate body (by 30%), whereas the theta rhythm decreased only in the visual cortex (by 10%). Possible mechanisms for these effects are discussed.

Animals↗
PubMedDate not supplied

[Change in the human electroencephalogram during brief mental loads].

Frequency-amplitude characteristics of EEG beta-, alpha-, theta- and delta-rhythms were studied in 33 male subjects with different maximal velocity of effective processing of visual information. Dosed mental load enhanced the total activity of EEG frequency components of parieto-occipital parts of the brain. The most substantial changes were revealed in the delta-rhythm range. A statistically significant correlative connection was found between integrative amplitude values of EEG slow rhythms and success in performing mental tasks. The higher the maximal velocity of effective processing of visual information, the greater the magnitudes of theta- and beta-activity. No statistically significant connection has been revealed between the maximal velocity of effective processing of visual information and the frequency-amplitude EEG characteristics before and after mental loads.

Adult↗
PubMed1992

Delta frequency (1-4 Hz) oscillations of perigeniculate thalamic neurons and their modulation by light.

Neurons in the perigeniculate sector of the reticular thalamic nuclear complex were recorded extra- and intracellularly under deep urethane anesthesia. They were identified by burst responses to optic chiasm stimulation and depolarizing spindle oscillations in response to internal capsule stimulation. Perigeniculate neurons displayed oscillations within the frequency range of electroencephalogram delta waves (1-4 Hz). One-third of extracellularly recorded neurons discharged rhythmic (2.5-4 Hz), high-frequency (150-200 Hz) spike bursts. This was similar to an intrinsic oscillation that was recently observed in dorsal lateral geniculate cells studied in vitro and in vivo. Other oscillating neurons displayed trains of single spikes (20-50 Hz) crowning rhythmic (2.5-4 Hz) depolarizing envelopes that were best expressed at the "resting" membrane potential (-60 to -65 mV). It is suggested that this oscillation reflects synaptic drives from dorsal lateral geniculate neurons. Changes in ambient room luminosity disrupted both types of delta rhythms. These data demonstrate for the first time that delta oscillations are present in the visual sector of the reticular thalamic nucleus. The results suggest that the two types of delta rhythmicity result from intrinsic and network properties of visual thalamic neurons and that perigeniculate cells may synchronize, through backward connections, the activity of dorsal lateral geniculate cells during deep stages of resting sleep.

Animals↗
PubMed1977

[Electroencephalographic parameters in psychomotor attacks (author's transl)].

An investigation of certain electroencephalographic parameters recorded during 19 psychomotor attacks was made. Each attack had been recorded in full. Fourteen of the attacks were preceded by a temporal focus, 13 were provoked by hyperventilation, 18 were initiated focally, 9 were accompanied by seizure potentials, 7 revealed primary or secondary delta rhythms, and 8 were followed by temporal delta focus.

Adolescent↗
PubMed1978

[Centrencephalic myoclonic-astatic petit mal. Clinical and electroencephalographic long-term follow-up study in 52 patients (author's transl)].

In this report 52 patients meeting the criteria of centrencephalic myoclonic-astatic petit mal (10) at the beginning of petit mal are included. The results of clinical and encephalographic follow-up examinations are as follows: 1) The type reported here apparently has a petit mal course with peculiar characteristics, it therefore must be separated from Lennox syndrome: centrencephalic myoclonicastatic petit mal, pyknolepsia, bilateral myoclonus (impulsive petit mal). It should file under generalized primary petit mal epilepsy. 2) It is primarily defined by its EEG marker: "centrencephalic" EEG pattern (irregular and/or regular spike-wave groups, photosensibility and abnormal theta- and/or delta-rhythm). Rarely (33%) minor cerebral organic lesions as additional pathogenetic factors are uncovered by clinical and electroencephalographic examinations. 3) The clinical picture is characterized, aside from myoclonic and/or astatic seizures, by frequent absences (80%), rare tonic seizures (6%), petit mal status (25%) and mostly generalized grand mal seizures (62%). 4) There are changes of the course of the disease to Lennox syndrome (N = 6) in in children suffering from marked cerebral organic lesions at the onset of petit mal and in development of severe epilepsy. 5) Least favorite markers with respect to prognosis are concomitant grand mal seizures (p = 0,05), petit mal status (p = 0.008), additional 2/sec spike wave-pattern (spike wave Variant) in the EEG (p = 0.002) and previous seizures with focal signs. Favourite outcome of epilepsy are frequently connected to missing cerebral organic lesions (p = 0.05).

Delta Rhythm↗
PubMedDate not supplied

[Effect of gamma-hydroxybutyrate on EEG pattern in epilepsy. Preliminary report].

Investigations were carried out in 50 patients with epilepsy who had been subjected previously to careful clinical examination. For the investigations the preparation Gamma-OH EGIC was used in doses of 0.03 g/kg of body weight in rapid intravenous injection. The preparation modified rapidly the EEG tracings which were divided into 4 phases: 1) phase of initial resting record, 2) disappearance of alpha rhythm with increase of medium and low-voltage theta rhythm, 3) high-voltage phase resembling sleep activity with prevalence of delta rhythm, 4) phase of desynchronization--return of normal activity. Out of 50 epileptics in 31 cases temporal-lobe epilepsy was present, in 15 the seizures and EEG changes were generalized, in 4 cases focal non-temporal-lobe epilepsy was recognized. Administration of Gamma-OH to epileptics caused in 100% of cases a modification of the initial tracings and in 84% activation of EEG changes mainly with activation of focal slow-wave activity; in cases of minor absence attacks the drug always induced paroksysmal activity. The preparation is safe and non-toxic and may be used in outpatient clinics. It seems that activation of EEG changes in epileptics by Gamma-OH administration may be due to disturbances of the equilibrium between the structures activating and inhibiting the reticular formation of the brain stem and cerebral cortex.

Adolescent↗
PubMedDate not supplied

Epidemiology of absence epilepsy: EEG findings and their predictive value.

This population-based study of absence epilepsy comprised 97 children, ranging in age from newborns to 15 years. All had regular bilaterally synchronous and symmetric 2-4 Hz spike-and-slow wave discharges and absences with or without generalized tonic-clonic seizures (GTCS). Patients without GTCS tended to have long episodes of 2-4 Hz spike-and-slow wave discharges (greater than or equal to 10 sec), and simultaneous clinical correlates more frequently than those with GTCS. Posterior delta rhythm was found only in patients without GTCS. Focal abnormalities, albeit transient, were more frequent among patients with GTCS. The initial electroencephalogram was of some early predictive value in patients with only absences at the time of the initial registration. Brief episodes of 2-4 Hz spike-and-slow wave (less than 10 sec) without clinical correlates were associated with a slightly increased risk of future GTCS.

Adolescent↗
PubMed1991

[Atypical electroencephalographic activity in terminal phase subacute sclerosing panencephalitis].

The authors describe the evolution of the EEG during a 3-yr period in a case of subacute sclerosing panencephalitis (SSPE) revealed by epilepsy in a 9 yr-old boy. During the first 2 yr, the EEG was markedly abnormal (diffuse spike-waves, delta rhythms). During the static period, it looked like a continuous non-convulsive status epilepticus. The typical periodic abnormal activity only appeared at the terminal stage, and after a Valium test. Then slow wave complexes persisted on a dysrhythmic background. This type of EEG has never been described; our study stressed the efficacy of the Valium test in this particular case.

Child↗
PubMed1992

Delta sleep-inducing-peptide-like immunoreactivity (DSIP-LI) and delta sleep in schizophrenic volunteers.

Delta sleep-inducing-peptide (DSIP) has been reported to increase sleep in subjects with insomnia. The authors studied cerebrospinal fluid (CSF) DSIP-like immunoreactivity (DSIP-LI) in 15 drug-free male subjects with a DSM-IIIR diagnosis of schizophrenia. The subjects underwent a lumbar puncture and three nights of polysomnography. CSF DSIP-LI was significantly correlated with polysomnography the night before the LP: with stage 3 sleep (p = 0.05), stage 3 and delta (stages 3 + 4) sleep during the first nonrapid eye movement NREM period (p = 0.02 and p = 0.05, respectively) and the ratio of the first and second NREM period (p < 0.05), and negatively with stage 2% sleep (p < 0.05). Whether this first report of a potential relationship between CSF DSIP-LI and slow-wave sleep in man might be generalized to sleep in nonpsychiatric subjects awaits further study.

Adult↗
PubMed1991

Daytime sleepiness in the healthy "old old": a comparison with young adults.

OBJECTIVE: To determine if excessive daytime sleepiness is an inevitable consequence of aging. METHODS: Daytime sleepiness was measured using Multiple Sleep Latency Tests (MSLT's) before and after a night of total sleep deprivation in a sample of 22 healthy men and women in their eighties and 29 men and women in their twenties. RESULTS: Young adults were somewhat sleepier than elders, as measured by rapidity of sleep onset during daytime nap recordings using the MSLT, and showed a higher incidence of REM sleep during naps. However, recovery from the effects of acute sleep loss was slower in the elderly, judging from the presence of more daytime sleepiness 2 days after a night of total sleep deprivation. Such persistent sleepiness was absent in the young adult control group. CONCLUSIONS: Healthy persons in late old age may have a level of daytime sleepiness no greater than, and perhaps even less than, that seen in healthy young adults.

Adult↗
PubMed1978

Disturbance of sleep by noise.

Young, middle-aged, and old subjects, 35 in all, were tested to determine the probability of disturbance of sleep, as judged by EEG records, by seven noises per night produced by a recording of a passing truck. There is roughly a linear relation with the A-weighted noise level. Young and old people have nearly the same response while middle-aged subjects are more sensitive by about 15 dB. This applies also to the probability of awaking. The probability of shifts in sleep to a shallower level does not appear to adapt in 24 successive nights with seven noises per night but the probability of waking drops to half value in about two weeks. Response increases with duration of the stimulus, at least over the limited range from fractions of a second to a minute.

Adolescent↗
PubMed1976

Dacrystic epilepsy.

We observed a 69 year old patient who had spontaneous paroxysmal attacks of weeping with lacrimation, contorted facies, and (usually) head-turning to the right. These episodes were followed by confusion and amnesia. During a pentylenetetrazol-evoked attack the EEG showed a right temporal delta rhythm. Atrophy, particularly of the right temporal regions, was noted on pneumoencephalography. We propose the term "dacrystic epilepsy" for this rare type of seizure disorder.

Aged↗
PubMed1979

Sleep electroencephalograms and sleep stages in hypoparathyroidism.

2 patients with hypoparathyroidism, one idiopathic and the other pseudoform, were studied by overnight polygraphic recording of the sleep EEG and related activities before and after start of treatment to investigate their sleep EEG patterns and states, with the results as follows. (1) Conspicuous abnormalities were noted in the sleep record, namely, disappearance of humps, spindles and hill waves, emergence of the mitten pattern and rather monotonous delta rhythm bursts. The EEGs, both awake and asleep, showed findings suggestive of a possible disorder of the desynchronizing mechanism of the brain stem. Normal sleep EEG patterns were restored after the serum calcium level had returned to the normal range. (2) In the course of overnight sleep, disturbance in the cyclic changes of sleep EEG pattern and absence of REM sleep were observed. Restoration to the normal course of sleep was achieved following the normalization of serum calcium level. Divalent calcium ion is considered to have intimate bearing upon the mechanism whereby synaptic chemical transmitters are activated. When viewed with reference to the monoamine hypothesis of Jouvet, the disturbance in the course of sleep observed in the present cases, especially the absence of or disturbed REM sleep, is inferred to be related to the hypocalcemia.

Child↗
PubMedDate not supplied

[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↗