Myriam Kerkhofs

EEG sleep patterns in man: a twin study

All-night EEG sleep recording was performed for 3 consecutive nights in 26 pairs of normal male twins (14 monozygotic and 12 dizygotic) in order to investigate genetic components of sleep. The analysis was based on average values of repeated sleep measures and controlled for the effect of cohabitation. Our results indicate that a significant proportion of variance in stages 2, 4 and delta sleep as well as in REM density is genetically determined in man. Genetic influences on stage 1 and REM are strongly confounded by a synchronizing effect of the cohabitational status.

Sleep EEG Variables in Young Schizophrenic and Depressive Patients

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Genetic determinants of EEG sleep: a study in twins living apart.

In order to investigate the genetic components of sleep and, in particular, of REM sleep, we performed 3 consecutive all-night EEG recordings in 26 pairs of normal male twins living apart (11 monozygotic and 15 dizygotic). Our results indicate that in man non-genetic rather than genetic influences substantially determine variance in stage REM, in contrast to stages 2, 4 and to delta sleep. In this sample of male twins, waking measures also showed a significant genetic component.

Fluoxetine in major depression: efficacy, safety and effects on sleep polygraphic variables.

Fluoxetine (60 mg), a selective inhibitor of the reuptake of 5-HT, was compared in a double-blind trial to amitriptyline (150 mg) in a sample of 34 patients fitting the Research Diagnostic Criteria for a major depressive disorder. Patients were studied after a drug washout period of 10 days and an active treatment period of 42 days. Sleep polygraphic recordings were performed before and at the end of the study. As indicated by the significant decrease in the Hamilton Depression scale and the Montgomery Asberg Depression scale, fluoxetine showed similar antidepressant effects to amitriptyline with significantly fewer adverse effects. Fluoxetine and amitriptyline decreased the amount of REM sleep, a well known effect of classical antidepressants. Fluoxetine showed some specific effects on sleep continuity (potentially dose related) as indicated by the significant increase in the number of awakenings and in stage shifts, without interfering with the therapeutic response.

Sleep EEG recordings in depressive disorders

Sleep polygraphic recordings were performed during 3 consecutive nights in a sample of 43 affectively ill inpatients. The patients were classified as major (n = 36) or minor depressive disorder (n = 7), according to the Research Diagnostic Criteria. Among the 36 patients with a major depressive disorder, 14 were in remission at the time of the sleep investigation. A two-way analysis of variance was performed to assess night and diagnostic effect on sleep variables. Shortening of REM latency was observed in depressed patients with major depressive disorder when compared to major depressive disorder patients in remission. Depressed patients with major depressive disorder also showed higher REM activity and REM density values than patients with minor depressive disorder. According to the linear discriminant analysis, sleep variables were able to correctly classify 68% of the patients.

Multivariate study of sleep EEG in depression

ABSTRACT— The effects of four subtypes of major depressive disorder on four sleep EEG variables obtained in 153 depressed inpatients were analyzed taking into account the effects of age, gender. DST response and severity of depression. We have found that age significantly affected slow wave sleep. Sleep efficiency and total sleep time were shown to vary with age and severity of depression. Such effects were not detected for REM latency which was influenced by the endogenous subtype and the gender. Our data indicate that in depressed patients sleep EEG measures are influenced by multiple factors.

Sleep during mania in manic-depressive males

SummarySleep polygraphic recordings were performed in six unmedicated male manics, in age and sex matched unipolar and bipolar depressives and in normal controls. No difference was evidenced between manics, depressives and controls when percentages of sleep stages 1, 2, 3, 4 and REM were considered. Manics demonstrated poorer sleep efficiency, longer sleep onset latency and reduced sleep period time than normal controls but no more so than in our depressed patients. None of the classical sleep disturbances reported in depression (short REM latency, decreased delta sleep and increased REM density) were observed in mania suggesting that with the exception of sleep continuity disturbances, sleep in mania is comparable to sleep in normal subjects.

The dexamethasone suppression test and sleep electroencephalogram in nonbipolar major depressed inpatients: A multivariate analysis

BACKGROUND The present study further examined relationships between postdexamethasone cortisol plasma values and sleep electroencephalogram (EEG) parameters. METHODS The dexamethasone suppression test (DST) and polysomnographic recordings were performed in a sample of 300 inpatients with primary major depressive disorder (MDD) (102 men and 198 women, mean age 44 +/- 12 years, range 20-74 years) consecutively admitted to Erasme Hospital (Brussels, Belgium) between 1981 and 1992. RESULTS The DST was abnormal in 40% of the sample. Postdexamethasone cortisol plasma values at 4:00 PM were significantly influenced by age, but not by gender. They were also significantly and positively correlated with weight loss, total scores on the Hamilton Depression Rating Scale, total scores on the Newcastle Scale, percentage of awakenings during sleep, and percent of stage 1. They were significantly and negatively correlated with percent of stage 2, slow-wave sleep, and REM sleep. Multiple regression analyses were conducted in two successive steps. First among clinical variables, only age and depressive symptom severity remained correlated with postdexamethasone plasma cortisol values. In the second step, with age and severity held constant, postdexamethasone plasma cortisol values were positively associated with amount of wake time and stage 1, and negatively with amount of slow-wave sleep. CONCLUSIONS These findings provide further indirect support for an overarousal state in MDD with sympathoadrenal system hyperactivity and impaired sleep continuity. They also underline the importance of taking into account various clinical confounding factors in the interpretation of both DST and sleep EEG results.

Genetic and environmental influences on prolactin secretion during wake and during sleep

To delineate the contributions of genetic and environmental factors in the regulation of human prolactin (PRL) secretion, the 24-h profile of plasma PRL was obtained at 15-min intervals in 10 pairs of monozygotic and 10 pairs of dizygotic twins. Sleep was monitored polygraphically. PRL secretory rates were derived from plasma concentrations by deconvolution. Diurnal (24-h) variations were quantified by a regression curve to define nadir, acrophase, and amplitude. Pulses of PRL secretion were identified using a computerized algorithm. A procedure specifically developed for twin studies was used to partition the variance into genetic and environmental contributions. Significant genetic effects were identified for daytime PRL concentrations, rhythm amplitude, and overall waveshape of the daily PRL profile. In contrast, environmental effects were dominant for mean concentrations during sleep, total secretory output during sleep, overall 24-h concentrations, and total 24-h secretion. However, when interindividual variations in sleep fragmentation were taken into account, the estimates of genetic variance for PRL concentrations and secretion during sleep approached statistical significance. Significant genetic influences were identified for slow-wave sleep (SWS). Because SWS is associated with increased nocturnal PRL secretion, it is possible that genetic effects on PRL secretion during sleep reflect genetic influences on SWS. In conclusion, genetic factors determine partially both the basal daytime concentrations of PRL and the temporal organization of PRL secretion over the 24-h cycle in normal young men.

Sleep EEG recordings in generalized anxiety disorder with significant depression

After one accommodation night, sleep EEG recordings were performed during three consecutive nights in ten drug-free inpatients presenting generalized anxiety disorder (GAD) with significant depression, compared with a age- and sex-matched group of patients with GAD and a group of primary major depressive disorder (MDD) patients. GAD patients with depression did not differ from GAD patients in any sleep variable. Patients with MDD showed more stage shifts and a greater number of awakenings than patients with GAD. REM latency was significantly shorter in MDD patients than in the other groups, and may thus help to differentiate anxious from depressed patients.