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PubMed1982

[Electroencephalographic rhythms during psychometric tests at 50 and 70 years of age].

The experiments were conducted to investigate changes occurring between maturity and old age in variations of the EEG when performing a series of mental tasks. Forty three normal male volunteers, divided in two age groups separated by 2 decades (52.9 +/- 0.2 yr, N = 22; 72.2 +/- 0.2 yr, N = 21), were continuously recorded by telemetry in 3 conditions: control, tests, questionnaires. Beta, alpha and theta rhythms and the number of slow waves were measured after visual EEG interpretation. The study showed that: (1) theta rhythms and slow waves were in higher proportions in men in their 70s; (2) variations induced by the various mental tasks were very similar at ages 50 and 70; (3) the two groups differed mostly in theta rhythm responses during tests with a coding task; (4) test performances and EEG indices were correlated only in the older group for theta rhythms.

Aged↗
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↗
PubMed1994

EEG features in juvenile migraine: topographic analysis of spontaneous and visual evoked brain electrical activity: a comparison with adult migraine.

Topographic analysis of spontaneous and steady-state visual evoked brain electrical activity was carried out between attacks in 82 migraine patients (40 youths and 42 adults). In adult migraine with aura a significant increase of delta rhythm percentage power was observed compared with migraine without aura and age-matched controls. Children suffering from migraine both with aura and without aura had an increased theta rhythm compared to normal controls. The presence of alpha interhemispheric asymmetry discriminated between migraine with aura and without aura, just as in adults. An increased amplitude of the SVEP F1 component with a tendency to the spread of visual reactivity was observed in juvenile migraine with and without aura; this pattern was not dissimilar from the one previously observed in adult migraine with and without aura. Abnormal photic driving in migraine is independent of age and type of migraine.

Adolescent↗
PubMed2001

Agrypnia excitata: clinical features and pathophysiological implications.

Fatal familial insomnia, Morvan's chorea and delirium tremens share the same clinical features: severe insomnia and mental confusion with dream enactment, associated with motor and autonomic activation. Polygraphically, they share an inability to generate slow wave sleep. Agrypnia excitata is the term which aptly defines this peculiar medical condition. In fatal familial insomnia, the syndrome is due to a functional imbalance between activating and deactivating structures within the limbic system provoked by the atrophy of the mediodorsal and anteroventral thalamic nuclei. In Morvan's chorea and delirium tremens, a functional imbalance within the thalamolimbic circuits might be explained by the accumulation of some antireceptor antibodies and by a transient prevalence of excitatory over inhibitory synapses, down-regulated by chronic alcohol abuse, respectively. The selective disappearance of slow sleep (i.e. sleep spindles and delta rhythms) characterizing the agrypnia excitata syndrome, together with other clinical and experimental findings, suggests that sleep can be divided into three types. The most archaic form of sleep corresponding to stage 1 non-REM sleep is shared by man and poikilothermic animals and generated within activating and deactivating neuronal poles located in the basal forebrain, hypothalamus and brain stem; the other two forms of sleep, slow wave sleep and paradoxical sleep, confined to homeothermic animals, are generated in the thalamus and pontine reticular formation respectively. 2001 Harcourt Publishers Ltd

Journal Article↗
PubMed2004

MRI-negative PET-positive temporal lobe epilepsy: a distinct surgically remediable syndrome.

Most patients with non-lesional temporal lobe epilepsy (NLTLE) will have the findings of hippocampal sclerosis (HS) on a high resolution MRI. However, a significant minority of patients with NLTLE and electroclinically well-lateralized temporal lobe seizures have no evidence of HS on MRI. Many of these patients have concordant hypometabolism on fluorodeoxyglucose-PET ([18F]FDG-PET). The pathophysiological basis of this latter group remains uncertain. We aimed to determine whether NLTLE without HS on MRI represents a variant of or a different clinicopathological syndrome from that of NLTLE with HS on MRI. The clinical, EEG, [18F]FDG-PET, histopathological and surgical outcomes of 30 consecutive NLTLE patients with well-lateralized EEG but without HS on MRI (HS-ve TLE) were compared with 30 consecutive age- and sex-matched NLTLE patients with well-lateralized EEG with HS on MRI (HS+ve TLE). Both the HS+ve TLE group and the HS-ve TLE patients had a high degree of [18F]FDG-PET concordant lateralization (26 out of 30 HS-ve TLE versus 27 out of 27 HS+ve TLE). HS-ve TLE patients had more widespread hypometabolism on [18F]FDG-PET by blinded visual analysis [odds ratio (OR = + infinity (2.51, -), P = 0.001]. The HS-ve TLE group less frequently had a history of febrile convulsions [OR = 0.077 (0.002-0.512), P = 0.002], more commonly had a delta rhythm at ictal onset [OR = 3.67 (0.97-20.47), P = 0.057], and less frequently had histopathological evidence of HS [OR = 0 (0-0.85), P = 0.031]. There was no significant difference in surgical outcome despite half of those without HS having a hippocampal-sparing procedure. Based on the findings outlined, HS-ve PET-positive TLE may be a surgically remediable syndrome distinct from HS+ve TLE, with a pathophysiological basis that primarily involves lateral temporal neocortical rather than mesial temporal structures.

Adult↗
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↗
PubMed1986

Sleep-wave activity of a delta sleep-inducing peptide analog correlates with its penetrance of the blood-brain barrier.

Delta sleep-inducing peptide (DSIP) significantly increases delta wave electrical activity in the brain of rats after intraperitoneal (i.p.) injection. Rats (n = 10) were peripherally injected with DSIP and [D-Ala4]DSIP-NH2 during the dark portion of a 12-h light/dark cycle prior to recording of epidural encephalographic (EEG) wave forms. Administration of [D-Ala4]DSIP-NH2, an analog that enters the brain after peripheral administration more readily than the parent DSIP molecule, resulted in significantly more delta waves than DSIP together with a highly significant amount of theta activity. DSIP was found to significantly increase EEG output in the delta range when compared with controls. In addition, the DSIP analog significantly decreased locomotor activity, whereas DSIP itself was without effect. These findings strongly support the controversial concepts that peripherally injected peptides can reach the brain and that DSIP compounds can increase sleep activity.

Animals↗
PubMed1986

Diurnal rhythm in appearance of frontal midline theta activity.

It has been reported that there is a certain rhythm in the appearance of Fm theta. In the present study, round-the-clock changes in the appearance of Fm theta were analyzed. The Uchida-Kraepelin test was conducted for 5 minutes a day over a period of 3 days on 18 university students. The span of time from 08:00 to 24:00 was divided into 9 temporal points and each subject was tested at 4 different points. EEGs were recorded and the changes in the appearance of Fm theta were investigated. As a result, it was found that there were signs of a frequent appearance of Fm theta in the morning, particularly between 10:00 and 12:00. Accordingly, it was evident that Fm theta appears at a certain diurnal rhythm.

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↗
PubMed2004

Melatonin advances the circadian timing of EEG sleep and directly facilitates sleep without altering its duration in extended sleep opportunities in humans.

The rhythm of plasma melatonin originating from the pineal gland and driven by the circadian pacemaker located in the suprachiasmatic nucleus is closely associated with the circadian (approximately 24 h) variation in sleep propensity and sleep spindle activity in humans. We investigated the contribution of melatonin to variation in sleep propensity, structure, duration and EEG activity in a protocol in which sleep was scheduled to begin during the biological day, i.e. when endogenous melatonin concentrations are low. The two 14 day trials were conducted in an environmental scheduling facility. Each trial included two circadian phase assessments, baseline sleep and nine 16 h sleep opportunities (16.00-08.00 h) in near darkness. Eight healthy male volunteers (24.4 +/- 4.4 years) without sleep complaints were recruited, and melatonin (1.5 mg) or placebo was administered at the start of the first eight 16 h sleep opportunities. During melatonin treatment, sleep in the first 8 h of the 16 h sleep opportunities was increased by 2 h. Sleep per 16 h was not significantly different and approached asymptotic values of 8.7 h in both conditions. The percentage of rapid eye movement (REM) sleep was not affected by melatonin, but the percentage of stage 2 sleep and sleep spindle activity increased, and the percentage of stage 3 sleep decreased. During the washout night, the melatonin-induced advance in sleep timing persisted, but was smaller than on the preceding treatment night and was consistent with the advance in the endogenous melatonin rhythm. These data demonstrate robust, direct sleep-facilitating and circadian effects of melatonin without concomitant changes in sleep duration, and support the use of melatonin in the treatment of sleep disorders in which the circadian melatonin rhythm is delayed relative to desired sleep time.

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↗
PubMed1982

Telemetered EEG in schizophrenia: spectral analysis during abnormal behaviour episodes.

In an attempt to detect electroencephalographic (EEG) changes associated with characteristic clinical signs and symptoms of schizophrenia, power spectra were derived from scalp EEGs of schizophrenic patients recorded by telemetry during free behaviour on their psychiatric wards. Power spectra from EEG epochs coincident with psychomotor blocking, stereotyped automatism or hallucinations were compared with spectra derived during periods of relatively normal behaviour, during performance of specific tasks and spectra from control subjects. Ramp spectra, characterised by a smooth decline in power from lowest to highest frequencies, previously found in conjunction with subcortical spike activity of epilepsy were not found in any control subject, but appeared in spectra from schizophrenic patients during catatonic episodes, hallucinatory periods and visual checking. Schizophrenic patients also had more slow activity and less alpha activity in their EEGs than normal control subjects.

Adult↗
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↗
PubMed1985

Hypercalcemic encephalopathy in the course of hyperthyroidism.

A hypercalcemic condition can be observed in association with hyperthyroidism. The case of a patient suffering from hypercalcemia and hyperthyroidism is reported. A confusional state and EEG alterations, among which diffuse monomorphic delta rhythms were remarkable, are shown. As soon as normalization of calcemia was achieved, a rapid clinical and EEG improvement took place. A hypothetical interpretation is proposed, according to which a prolonged, though inconstant, and mild hypercalcemia in the course of hyperthyroidism could determine an encephalopathy, concealing in some way thyrotoxic symptoms.

Brain Diseases↗
PubMed1983

The COMSTAT algorithm for multimodal factor analysis: an improvement of Tucker's three-mode factor analysis method.

Three-mode factor analysis, as developed by Tucker in 1966, is a method for nonredundant representation of data arrays with three subscripts (e.g. observations classified according to persons by variables by conditions). Tucker , however, did not succeed in obtaining a least-squares solution for his model. We derive in this paper a necessary condition for a least-squares solution and construct an algorithm which improves any given initial solution in the least-squares sense. We show that this algorithm converges to a representation satisfying the necessary conditions for a least-squares solution. The method is in no way restricted to three dimensions, but can be applied to any multimodal data array.

Alpha Rhythm↗
PubMed1998

Crepuscular rhythms of EEG sleep-wake in a hystricomorph rodent, Octodon degus.

Sleep-wake circadian rhythms are well documented for nocturnal rodents, but little is known about sleep regulation in diurnal or crepuscular rodent species. This study examined the circadian sleep-wake rhythms in Octodon degus by means of electroencephalogram (EEG) analysis. Recordings were made from animals housed with or without running wheels in the cages. In a 24-h light-dark (LD) cycle (LD 12:12), sleep and wake patterns were highly fragmented under both conditions except for crepuscular timed episodes of waking. Without running wheels, sleep bout lengths averaged 3.7 +/- 0.1 min, and total sleep time was 37.6 +/- 3.7% per 24 h. Although the percentage of total wakefulness was similar during the light phase (63.4 +/- 2.4%) and dark phase (61.5 +/- 2.8%), measures of locomotor activity (LMA) and body temperature were generally greater during the day than during the night. Without running wheels, EEG slow wave activity (SWA) in nonrapid eye movement (NREM) sleep exhibited a circadian waveform that was elevated only during the light phase. SWA peaked at Zeitgeber Time 7 (ZT 7) (several hours after the dominant waking episode at ZT 23), then declined across the later half of the light phase and into the dark phase. Voluntary wheel running did not alter daily total sleep time, the duration of average sleep bouts, or maximum sleep bouts, but it increased the episode of waking, LMA, and body temperature at ZTs 11-12. Under these conditions, NREM sleep and SWA exhibited crepuscular patterns, with elevated SWA during the day and night. Although Octodon degus exhibited no strong preference for sleep during the light or dark phase, these data suggest that in this species homeostatic sleep responses (indicated by SWA) are gated by the dominant crepuscular episode(s) of waking and can be influenced by wheel running.

Animals↗