Anna S. Urrila

Sleep and the menopause - do postmenopausal women experience worse sleep than premenopausal women?

Objective To examine the sleep characteristics in three cross-sectional populations: young, premenopausal and postmenopausal women, and the associations between sleep, menopause, mood and cognitive performance. Study design Twenty-one premenopausal (45–51 years), 29 postmenopausal (59–71 years) and 11 young (20–26 years, using oral contraceptives) women were recruited. Polysomnography was used to measure objective sleep quality. Subjective sleep quality, sleepiness and mood were assessed using questionnaires. Cognitive performance was investigated by means of three attentional tests. Results Total sleep time in pre- and postmenopausal women was similar (404.9 and 384.7 minutes), but shorter than in young women (448.2 minutes, P = 0.030 and <0.003, respectively). Sleep efficiency followed the same pattern, being 84.3% in premenopausal (P = 0.027), 80.2% in postmenopausal (P < 0.003) and 93.4% in young women. Pre- and postmenopausal women had less slow wave sleep (duration or activity) and more wake time after sleep onset (duration or frequency). Insomnia complaints were more frequent after the menopause (P = 0.023). Sleepiness and mood scores were similar in all groups. Reaction speeds slowed with increasing age. After the menopause, better cognitive performance was associated with more rapid eye movement sleep. Conclusion Objective sleep measures differed significantly between the young and postmenopausal groups. These differences may be more because of the physiology of ageing than the rapid changes across the menopause, since similar sleep characteristics were already present in the premenopausal women. The increase in sleep complaints after menopause was not associated with sleepiness or disturbances in objective sleep quality, mood or cognitive performance.

Stimulus‐induced brain lactate: effects of aging and prolonged wakefulness

Both aging and sleep deprivation disturb the functions of the frontal lobes. Deficits in brain energy metabolism have been reported in these conditions. Neurons use not only glucose but also lactate as their energy substrate. The physiological response to elevated neuronal activity is a transient increase in lactate concentrations in the stimulated area. We have previously shown that cognitive stimulation increases brain lactate. To study the effect of prolonged wakefulness on the lactate response we designed an experiment to assess brain lactate levels during a 40‐h sleep deprivation period in young (19–24 years old; n = 13) and in aged (60–68 years old; n = 12) healthy female volunteers. Brain lactate levels were assessed with proton MR‐spectroscopy (1H MRS) during the performance of a silent word generation task. The 1H MRS voxel location was individually selected, using functional magnetic resonance imaging, to cover the activated area in the left frontal lobe. The degree of sleepiness was verified using vigilance tests and self‐rating scales. In the young alert subjects, the silent word generation test induced a 40% increase in lactate, but during the prolonged wakefulness period this response disappeared. In the aged subjects, the lactate response could not be detected even in the alert state. We propose that the absence of the lactate response may be a sign of malfunctioning of normal brain energy metabolism. The behavioral effects of prolonged wakefulness and aging may arise from this dysfunction.

Metabolic imaging of human cognition: An fMRI/1H-MRS study of brain lactate response to silent word generation

Proton magnetic resonance spectroscopy (1H-MRS) allows in vivo assessment of the metabolism related to human brain functions. Visual, auditory, tactile, and motor stimuli induce a temporary increase in the brain lactate level, which may act as a rapid source of energy for the activated neurons. The authors studied the metabolism of the frontal lobes during cognitive stimulation and measured local lactate levels with standard 1H-MRS, after localizing the activated area by functional MRI. Lactate levels were monitored while the subjects either silently listed numbers (baseline) or performed a silent word-generation task (stimulus-activation). The cognitive stimulus-activation produced a 50% increase in the brain lactate level in the left inferior frontal gyrus. The results show that metabolic imaging of neuronal activity related to cognition is possible using 1H-MRS.

Adenosine, Energy Metabolism, and Sleep

While the exact function of sleep remains unknown, it is evident that sleep was developed early in phylogenesis and represents an ancient and vital strategy for survival. Several pieces of evidence suggest that the function of sleep is associated with energy metabolism, saving of energy, and replenishment of energy stores. Prolonged wakefulness induces signs of energy depletion in the brain, while experimentally induced, local energy depletion induces increase in sleep, similarly as would a period of prolonged wakefulness. The key molecule in the induction of sleep appears to be adenosine, which induces sleep locally in the basal forebrain.

Hormone Treatment Gives No Benefit Against Cognitive Changes Caused by Acute Sleep Deprivation in Postmenopausal Women

The objective was to evaluate whether hormone therapy (HT) gives any benefit against the possible impairment of cognitive performance when challenged by acute sleep deprivation. Twenty postmenopausal women volunteered (age range 59–72 years, mean=64.4 years, SD=4.4): 10 HT users and 10 nonusers. Eleven young women served as a control group for the cognitive age effect (age range 20–26 years, mean age 23.1 years, SD=1.6). The subjects spent four consecutive nights at the sleep laboratory and were exposed to acute sleep deprivation of 40 h. Measures of attention (reaction speed and vigilance), alertness, and mood were administered every 2 h during the daytime and every hour during the sleep deprivation night. Postmenopausal women performed slower than young controls, whereas young controls made more errors. In HT users, the recovery night did not fully restore the performance in the simple and two-choice reaction time tasks, but in nonusers it did so. Sleep deprivation had a detrimental, yet reversible effect on vigilance in all groups. In all groups, sleepiness started to increase after 15 h of sleep deprivation and remained elevated in the morning after the recovery night. Prolonged wakefulness or HT had no effect on mood. In conclusion, sleep deprivation impaired cognitive performance in postmenopausal as well as young women. Postmenopausal women kept up their performance at the expense of reaction speed and young women at the expense of accuracy. One night was not enough for HT users to recover from sleep deprivation. Thus, HT gave no benefit in maintaining the attention and alertness during sleep deprivation.

The relationship between mood and sleep in different female reproductive states

BackgroundSleep is disrupted in depressed subjects, but it also deteriorates with age and possibly with the transition to menopause. The nature of interaction between mood, sleep, age and reproductive state is not well-defined. The aim of this study was to evaluate the relationship between mood and sleep among healthy women in different reproductive states.MethodsWe analyzed data from 11 younger (20–26 years), 21 perimenopausal (43–51 years) and 29 postmenopausal (58–71 years) healthy women who participated in a study on menopause, sleep and cognition. The 21-item Beck Depression Inventory (BDI) was administered to assess mood. Subjective sleep quality was assessed with the Basic Nordic Sleep Questionnaire (BNSQ). Objective sleep was measured with all-night polysomnography (PSG) recordings. Perimenopausal and younger women were examined during the first days of their menstrual cycle at the follicular phase.ResultsAmong younger women, less arousals associated with higher BDI total scores (p = 0.026), and higher SWS percentages with more dissatisfaction (p = 0.001) and depressive-somatic symptoms (p = 0.025), but with less depressive-emotional symptoms (p = 0.001). In specific, less awakenings either from REM sleep or SWS, respectively, associated with more punishment (p = 0.005; p = 0.036), more dissatisfaction (p < 0.001; p = 0.001) and more depressive-somatic symptoms (p = 0.001; p = 0.009), but with less depressive-emotional symptoms (p = 0.002; p = 0.003). In perimenopausal women, higher BNSQ insomnia scores (p = 0.005), lower sleep efficiencies (p = 0.022) and shorter total sleep times (p = 0.024) associated with higher BDI scores, longer sleep latencies with more depressive-somatic symptoms (p = 0.032) and longer REM latencies with more dissatisfaction (p = 0.017). In postmenopausal women, higher REM percentages associated with higher BDI total scores (p = 0.019) and more depressive-somatic symptoms (p = 0.005), and longer SWS latencies with more depressive-somatic symptoms (p = 0.030).ConclusionsDepressive symptoms measured with the total BDI scores associated with sleep impairment in both perimenopausal and postmenopausal women. In younger women, specific BDI factors revealed minor associations, suggesting that the type of sleep impairment can vary in relation to different depressive features. Our data indicate that associations between sleep and depressed mood may change in conjunction with hormonal milestones.

Cardiac autonomic changes after 40 hours of total sleep deprivation in women

OBJECTIVES The effect of total sleep deprivation on heart rate variability (HRV) in groups of postmenopausal women on oral hormone therapy (HT) (on-HT, n = 10, 64.2 (1.4) years), postmenopausal women without HT (off-HT, n = 10, 64.6 (1.4) years) and young women (n = 11, 23.1 (0.5) years) was studied using a prospective case-control setup. METHODS Polysomnography was performed over an adaptation night, a baseline night, and a recovery night after 40 h of total sleep deprivation. Time and frequency domain and nonlinear HRV from overnight electrocardiogram recordings were compared between groups during baseline and recovery nights. Further, the changes in HRV from baseline to recovery were analysed and compared between groups. Finally, correlations of HRV to percentages of sleep stages and measures of sleep fragmentation were analysed during baseline and recovery. RESULTS Young women had higher HRV than older women; the most marked difference was between young and on-HT postmenopausal women. Sleep deprivation induced a decrease in frequency domain HRV in young and in off-HT women, an increase in α2 in off-HT women, and an increase in mean heart rate in on-HT women. The sleep deprivation effect was mainly uncorrelated to changes in sleep parameters. CONCLUSIONS Acute total sleep deprivation has a deleterious effect on the autonomic nervous system in young women, but an even more pronounced effect in postmenopausal women. Hormone therapy use in late postmenopause does not give protection against these changes. These harmful effects may partly explain the increased cardiovascular morbidity and overall mortality associated with sleep loss.

Sleep habits, academic performance, and the adolescent brain structure

Here we report the first and most robust evidence about how sleep habits are associated with regional brain grey matter volumes and school grade average in early adolescence. Shorter time in bed during weekdays, and later weekend sleeping hours correlate with smaller brain grey matter volumes in frontal, anterior cingulate, and precuneus cortex regions. Poor school grade average associates with later weekend bedtime and smaller grey matter volumes in medial brain regions. The medial prefrontal - anterior cingulate cortex appears most tightly related to the adolescents’ variations in sleep habits, as its volume correlates inversely with both weekend bedtime and wake up time, and also with poor school performance. These findings suggest that sleep habits, notably during the weekends, have an alarming link with both the structure of the adolescent brain and school performance, and thus highlight the need for informed interventions.

First-Night Effect on Sleep in Different Female Reproductive States

ABSTRACT Objectives: In sleep laboratory studies, the new environment is generally considered to disturb sleep during the first night. However, older women have rarely been studied. Although menopause and hormone therapy affect sleep, their impact on the first-night effect is virtually unknown. Participants: Four groups of women with no sleep laboratory experience: young on hormonal contraceptives (n = 11, 23.1 [0.5] years), perimenopausal (n = 15, 48.0 [0.4] years), postmenopausal without hormone therapy (HT; off-HT, n = 22, 63.4 [0.8] years) and postmenopausal with HT (n = 16, 63.1 [0.9] years). Procedure: A cross-sectional study. Methods: Polysomnography was performed over two consecutive nights and the first-night effect and group differences were evaluated. Questionnaire-based insomnia and sleepiness scores were correlated to sleep variables and their between-night changes. Results: Although sleep in young women was deeper and less fragmented than in the other groups, first-night effect was similar in all study groups. Total sleep time, sleep efficiency, and S1 and S2 sleep increased, and wake after sleep onset, awakenings per hour of sleep, S2 and REM latencies, and percentage of SWS decreased from the first to the second night. Perimenopausal women had more insomnia complaints than other women. Insomnia complaints were associated with more disturbed sleep but not with the first-night effect. Conclusions: A first night in a sleep laboratory elicits a marked interference of sleep architecture in women of all ages, with a carryover effect of lighter sleep on the second study night. Menopausal state, HT use, or insomnia complaints do not modify this effect.

Advanced phases and reduced amplitudes are suggested to characterize the daily rest-activity cycles in depressed adolescent boys

Abstract Self-reported eveningness has been previously associated with depressed mood among adults and adolescents. Here, we study how circadian indicators based on actigraphic data differ between depressed and healthy adolescent boys. Our sample consisted of 17 medication-free adolescent boys, aged 14.5 to 17.5 years, of which eight had depressive disorder and were currently depressed and nine were healthy comparison participants. Psychiatric assessment was conducted by diagnostic interviews and complemented with observer-rating and self-rating scales. Actigraphic data were collected with wrist actigraphs for a minimum period of 25 consecutive days (range of 25 to 44 days). The behavioral trait of morningness–eveningness was measured with the 19-item Horne-Östberg Morningness–Eveningness Questionnaire. Based on the self-report, the depressed boys were more prone to eveningness than healthy controls, but based on the actigraphic data, they had earlier phases especially on school days and lower activity levels especially on weekends. On weekends, the depressed boys showed a greater shift toward later-timed phases than healthy controls. Our results confirm a mismatch of the subjective morningness–eveningness preference (late-preference) and the objective rest-activity rhythm (early-prone) during school days in depressed adolescent boys.