Biomedical subjects
B van Sweden
Publications and source records attributed to B van Sweden.
Electrical brain activity in preterm infants at risk for intracranial hemorrhage.
We studied the effect of preterm birth on electroencephalographic background activity in 20 infants < 32 weeks' gestation. Six infants developed periventricular-intraventricular hemorrhage during the study period. Four-channel 24-h cassette recordings were obtained on day 1, 3-5 and 7-9. For each of the 24-h recordings, the percentage of the time showing stage I (continuous activity), stage II (mixed activity) and stage III (discontinuous activity) epochs was calculated. In infants without periventricular-intraventricular hemorrhage, a positive linear relationship between gestational age and continuous activity and a negative linear relationship between gestational age and discontinuous activity existed in the first day recordings; in infants with periventricular-intraventricular hemorrhage, such relationships were not found. To determine if the changes in continuous and discontinuous activities during the first week of extrauterine life were different from the expected changes during a corresponding time in utero, we calculated the expected amounts of stage I and III changes for each infant. The actual changes were not significantly different from the expected values in both study groups. However, during the onset and/or extension of periventricular-intraventricular hemorrhage, depression of the electroencephalographic background activity was found.
Auditory information processing in sleep: habituation to repetitive stimuli.
Habituation to evoked responses is obvious in waking but still controversial in sleep. Single-response analysis proves short-term habituation of auditory evoked potentials in stage 2 NREM sleep. The data are discussed referring to the two-system hypothesis of sensory processing in sleep and to DC instability and sleep maintenance mechanisms in stage 2 NREM. It is suggested that information processing might continue in sleep.
[Sleeping disorders and drowsiness during the day, a hard to evaluate problem].
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Aging of core and optional sleep.
Two consecutive 24-hr ambulatory recordings of 14 healthy elderly persons (7 women, 7 men, ages 88-102) and of 19 healthy young adults (10 women, 9 men, ages 25-35) were evaluated. In addition to the classical sleep parameter analysis, sleep structure was also analyzed in terms of a proposed distinction between "core" and "optional" sleep (Horne 1989). Core sleep is the essential part of the sleep and is mainly slow wave sleep. This type of sleep is composed of stages 3 and 4 on non-REM sleep (NREM 3-4). Core sleep is obtained during the first three sleep cycles and the remainder of the night sleep is considered optional sleep. Optional sleep is more altered than core sleep. However, in both optional and core sleep, NREM sleep and REM are reduced. There is also an increase in drowsiness and in the time spent awake after sleep onset; however, the extent of these effects are more obvious in elderly men. Aging effects of slow wave sleep probably represent an amplification of the changes as observed in awake electroencephalic (EEG) patterns in healthy seniors. The decrease in slow wave sleep (stages NREM 3-4) is gender related and prevails in elderly men. REM sleep diminishes with increasing age. In the elderly, most REM sleep occurs at the beginning of the night. This contrasts to younger persons where the duration of REM sleep is longer at the end of the night. Furthermore, a decrease in REM sleep latency is particularly obvious in elderly men and probably secondary to the curtailment of slow wave sleep. The ultradian NREM-REM cycle rhythm (as defined by the periodic occurrence of REM sleep) shows a monophasic trend suggesting a diminished adaptive function of aged sleep. The informative value of true, continuous ambulatory recordings in the assessment of sleep-wakefulness patterns in normal and pathological aging is stressed.
Ambulatory monitoring of sleep-wakefulness patterns in healthy elderly males and females (greater than 88 years): the "Senieur" protocol.
OBJECTIVE: The study was designed to investigate sleep-wake patterns in healthy elderly men and women (greater than 88 years) using ambulatory recording techniques. DESIGN: Cross-sectional observations on 2 consecutive days. METHODS: Two consecutive 24-hour recordings were made. Each 30-second period of the recording was scored as characteristic of wakefulness, REM, and non-REM sleep (stages 1-4). SETTING: Interviews and recordings were done in the home of the elderly, not interfering with the habitual routine. PARTICIPANTS: Among eligible members of the "Senieur" protocol, screened for wellness, seven females (88-102 years) and seven males (88-98 years) volunteered to participate. MAIN OUTCOME MEASURES: Organization of sleep, sleep structure, and daytime mapping. RESULTS: There was no difference between the first and second night recording. Important gender differences were observed: males had significantly less total sleep, shorter REM latency, more transitions to wake from REM, less NREM 3 sleep, and virtually no NREM 4. Daytime napping, REM amount, and distribution did not show sex differences. Although the variability in the amount of napping was considerable, it occupied less than 10 percent of the total sleep time in both women and men. Daytime napping was unrelated to sleep characteristics. CONCLUSIONS: Ambulatory sleep-wake recordings allow an objective and critical evaluation of sleep function in normal aging. Interesting findings include a shift of REM sleep to the first part of the sleep period an increased cycle variability, and non-correlation of night-time sleep with daytime napping. In contrast to earlier findings in elderly persons, a polygraphic and subjective first-night effect was lacking.
Ambulatory first night sleep effect recording in the elderly.
The concept of a first night effect on sleep patterns, specifically in relation to age is a controversial topic in the literature. Our data are obtained during two consecutive 24-h ambulatory home sleep-wake recording in 10 elderly persons with a mean age of 85.5 years. Polysomnographic recordings indicated that a first night effect is present in old age, even using home recording, and that several types of insomnia can be differentiated, stressing that sleep cycle parameters should be taken into account. It is suggested that the first night effect is a 'miniature' replication of a psychophysiological insomnia.
Ambulatory monitoring in sleep apnoea presenting with nocturnal episodic phenomena.
Episodic nocturnal phenomena represent a separate cluster of disturbances within the classification of sleep disorders. The reported case history covers paroxysmal signs occurring secondary to a REM-dependent mixed sleep apnoea syndrome. The pathophysiology of similar episodes in elderly (non)epileptic patients is discussed. Ambulatory monitoring is an appropriate technique for investigation if respiratory and motor activity, and EEG and ECG are recorded simultaneously.
Alternative electrode placement in (automatic) sleep scoring (Fpz-Cz/Pz-Oz versus C4-A1).
The purpose of this study is to investigate whether the international standard electrode placement (C4-A1) can be replaced by an alternative placement (Fpz-Cz/Pz-Oz) in an automatic sleep monitoring system without losing Rechtschaffen and Kales (R-K) balances. Single night-sleep polygraphic recordings of 10 patients, screened in a clinical sleep disorder setting, were recorded simultaneously with both placements, and visual sleep classification was performed separately by two independent observers. Interobserver and interplacement agreement were evaluated by way of average (dis)agreement matrices and kappa values computed for overall and individual stage scoring. Interobserver agreement for both the test and the standard electrode placements and interplacement agreement for both observers were assessed as fair to good or excellent. Scoring differences were evaluated by the rank sign test applied to clinical and theoretical difference scores. It appears that the interplacement differences are about equal to the interobserver differences, except for a slight tendency for sleep to be scored in a deeper stage with the proposed alternative placement. The data are presented and discussed in relation to current literature concepts.
Toxic ictal delirium.
Delirium, also known as acute confusional state, is a common reversible organic psychiatric syndrome. This paper focuses on toxic delirium associated with prominent paroxysmal electroencephalogram (EEG) dysfunction occurring in nonepileptic patients. Our data derive from observations in two conditions, viz., delirium induced by hypnosedative drug withdrawal and confusion activated by psychotropic drug overdosage. It is suggested that in these conditions, delirium represents a generalized symptomatic nonconvulsive epileptic state following a transient transmitter dysfunction. Dramatic relief of both clinical and EEG dysfunction by intravenous benzodiazepines is reported in detail. Finally, the informative value of the EEG in the differential diagnosis of acute confusional states is emphasized.
[Neurotoxicity of lithium with normal lithium levels].
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Diazepam loading for alcohol withdrawal: seizure risk in epileptics.
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[Old and on the bottle again: a double stigma].
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EEG dysfunction in geropsychiatry.
Electro-clinical correlations are reported in 200 elderly patients admitted to a psychiatric ward of a general hospital. Normal EEG characteristics were generally associated with functional psychiatric disorder. Abnormal EEG features correlated with organic brain syndromes (O.B.S.). The diagnostic and pathogenetic considerations and restrictions of EEG foci, intermittent rhythmic delta activity (Irda) and diffuse EEG slowing are discussed. The informative value of EEG dysfunction in geropsychiatry is emphasised.
Rebound insomnia in neuroleptic drug withdrawal neurophysiologic characteristics.
Rebound insomnia is one of the medical effects of reduction in dosage or discontinuation of neuroleptic drugs. The electrophysiologic features of sleep dysfunction are reported and discussed in 3 patients manifesting withdrawal-related DIMS. Electrographic anachronism and cyclic alternating pattern are signs of N-Rem sleep dysfunction. Clinical and neurophysiologic data suggest that rebound insomnia in neuroleptic withdrawal is due to an enhancement of physiologic mechanisms and rebound supersensitivity of cholinergic transmission in the ARAS.
Are complex partial seizures an uncommon withdrawal sign in the elderly?
An elderly female alcohol and benzodiazepine addict presented with an atypical amnestic episode. Five days later she showed several complex partial seizures as main signs of a withdrawal state. The value of the EEG in the differential diagnosis of amnestic syndromes is emphasized. Temporolimbic involvement in withdrawal states is discussed and our ignorance regarding drug dependence and withdrawal in the elderly is stressed. It is suggested that late-onset partial seizures with unknown etiology in the elderly might be more often related to drug dependence than generally accepted.
Patterns of EEG dysfunction in general hospital psychiatry.
Patterns of EEG dysfunction in clinical psychiatry are badly documented. Population variables in patients admitted to the psychiatric ward of a general hospital (n = 1,285) compared to a sample referred for EEG recording (n = 1,200) are reported. Prevalence of EEG dysfunction in referrals is high (42.5%) and the reported selection criteria appear clinically valid. The type of EEG dysfunction largely depends on age and recognizable patterns in general hospital psychiatry include drug effects, epilepsy in mental retardation and organic brain syndromes in the elderly. Similar data in other types of mental institutions are highly mandatory.
Valproate as psychotropic agent. Interactions and adverse cerebral reactions.
Recent data stress the psychotropic actions of valproate in schizo-affective disorder. Four patients are reported presenting an altered state of consciousness and prominent EEG dysfunction following combined valproate/neuroleptic drug treatment. Similar cerebral reactions have been reported in anti-epileptic poly- and monotherapy, and the pathogenetic considerations are discussed. Further investigations of the interactions of valproate with other psychotropic agents are highly mandatory.