Today, prolonged wakefulness is a widespread phenomenon. Nevertheless, in the field of sleep and wakefulness, several unanswered questions remain. Prolonged wakefulness can be due to acute total sleep deprivation (SD) or to chronic partial sleep restriction. Although the latter is more common in everyday life, the effects of total SD have been examined more thoroughly. Both total and partial SD induce adverse changes in cognitive performance. First and foremost, total SD impairs attention and working memory, but it also affects other functions, such as long-term memory and decision-making. Partial SD is found to influence attention, especially vigilance. Studies on its effects on more demanding cognitive functions are lacking. Coping with SD depends on several factors, especially aging and gender. Also interindividual differences in responses are substantial. In addition to coping with SD, recovering from it also deserves attention. Cognitive recovery processes, although insufficiently studied, seem to be more demanding in partial sleep restriction than in total SD.

Sleep deprivation: Impact on cognitive performance

Light has profoundly influenced the evolution of life on earth. As widely appreciated, light enables us to generate images of our environment. However, light - through intrinsically photosensitive retinal ganglion cells (ipRGCs) - also influences behaviours that are essential for our health and quality of life but are independent of image formation. These include the synchronization of the circadian clock to the solar day, tracking of seasonal changes and the regulation of sleep. Irregular light environments lead to problems in circadian rhythms and sleep, which eventually cause mood and learning deficits. Recently, it was found that irregular light can also directly affect mood and learning without producing major disruptions in circadian rhythms and sleep. In this Review, we discuss the indirect and direct influence of light on mood and learning, and provide a model for how light, the circadian clock and sleep interact to influence mood and cognitive functions.

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Light as a central modulator of circadian rhythms, sleep and affect

The Global Problem of Insufficient Sleep and Its Serious Public Health Implications

Sleep deprivation and hippocampal vulnerability: Changes in neuronal plasticity, neurogenesis and cognitive function

OBJECTIVE: To examine the impact of moderate sleep extension and restriction on child behavior in school. METHODS: We conducted a randomized parallel group study to determine the impact of an experimental sleep extension (addition of 1 hour of sleep relative to baseline habitual sleep duration on weekdays) and experimental sleep restriction (elimination of 1 hour of sleep relative to baseline habitual sleep duration on weekdays) on child behavior in school. The primary outcome measures were scores on the Conners’ Global Index Scale, as determined by teachers blinded to sleep status of the participants. A sample of 34 typically developing children aged 7 to 11 years with no reported sleep problems and no behavioral, medical, or academic issues participated in the study. RESULTS: Our main findings were that (1) a cumulative extension of sleep duration of 27.36 minutes was associated with detectable improvement in Conners’ Global Index–derived emotional lability and restless-impulsive behavior scores of children in school and a significant reduction in reported daytime sleepiness; and (2) a cumulative restriction of sleep of 54.04 minutes was associated with detectable deterioration on such measures. CONCLUSIONS: A modest extension in sleep duration was associated with significant improvement in alertness and emotional regulation, whereas a modest sleep restriction had opposite effects.

/pdf/impact-of-sleep-extension-and-restriction-on-children-s-1yi2ds5h8t.pdf

Impact of Sleep Extension and Restriction on Children’s Emotional Lability and Impulsivity

ObjectiveTo examine the sleep characteristics in three cross-sectional populations: young, premenopausal and postmenopausal women, and the associations between sleep, menopause, mood and cognitive ...

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

OBJECTIVE: To study the effects of sleep deprivation on cognitive performance in postmenopausal women and to evaluate whether hormone therapy (HT) has a modifying effect on coping. DESIGN: Twenty-six postmenopausal women, aged 58 to 72 years (mean 64 years), volunteered for the study (HT users, n = 16; nonusers, n = 10). They spent four consecutive nights in the sleep laboratory. The cognitive tests were performed three times: after the baseline night, after one night of sleep deprivation, and after the rebound night. The cognitive measures included visual episodic memory, visuomotor performance, verbal attention, and shared attention. RESULTS: The practice effect typically occurring in cognitive tests was blunted during sleep deprivation, which indicated deterioration of performance. At rebound, performance improved in visual episodic memory (immediate recall P < 0.01; delayed recall P < 0.05), visuomotor performance (P < 0.001), verbal attention (P < 0.0001), and shared attention (P < 0.05). HT users performed better than nonusers in the visual episodic memory test (P < 0.05) and in one of three subtests of shared attention (cancellation P = 0.040). Otherwise hormone therapy did not influence the results. CONCLUSIONS: In postmenopausal women, sleep deprivation impaired visual functions and attention. However, this effect was not prolonged because after one rebound night the performance was improved, compared with baseline. Hormone therapy did not modify the cognitive performance during sleep deprivation.

Sleep deprivation, cognitive performance, and hormone therapy in postmenopausal women.

Aims: The use of hormone therapy (HT) is a relevant and topical issue in the treatment of menopausal symptoms in women. Information regarding the effects of combination treatment with estrogen and progesterone as well as treatment timing on cognitive function is lacking and was evaluated in healthy pre- and postmenopausal women.



Methods:  Sixteen premenopausal (45–51 years) and 16 postmenopausal (58–70 years) women were randomly assigned to receive either estrogen + progestin therapy (HT) or placebo (PL) for six months. The study was double-blind. Cognitive performance was measured at baseline and follow up with tests of verbal and visuomotor functions, verbal and visual memory, and attention.



Results:  In premenopausal women, cognitive attention, when compared to baseline, improved with HT but declined slightly with PL in the two-choice reaction time task (P = 0.049), while PL was associated with better performance in tests of shared attention (P = 0.024) and auditory attention (P < 0.05). In postmenopausal women, HT was associated with improved performance in verbal episodic memory (P = 0.024) and a minor decline in auditory attention (P = 0.025).



Conclusions:  HT, with estradiol valerate and norethisterone, in healthy women showed only minor effects on attention around the menopausal transition and on memory in postmenopause.

Paula Alhola

Papers

Sleep deprivation: Impact on cognitive performance

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

Sleep deprivation, cognitive performance, and hormone therapy in postmenopausal women.

Estrogen + progestin therapy and cognition: A randomized placebo-controlled double-blind study

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