Sleep disruption explains age-related prospective memory deficits: implications for cognitive aging and intervention

The high prevalence of sleep disruption among older adults may have implications for cognitive aging, particularly for higher-order aspects of cognition. One domain where sleep disruption may contribute to age-related deficits is prospective memory—the ability to remember to perform deferred actions at the appropriate time in the future. Community-dwelling older adults (55–93 years, N = 133) undertook assessment of sleep using actigraphy and participated in a laboratory-based prospective memory task. After controlling for education, sleep disruption (longer awakenings) was associated with poorer prospective memory. Additionally, longer awakenings mediated the relationship between older age and poorer prospective memory. Other metrics of sleep disruption, including sleep efficiency and wake after sleep onset, were not related to prospective memory, suggesting that examining the features of individual wake episodes rather than total wake time may help clarify relationships between sleep and cognition. The mediating role of awakening length was partially a function of greater depression and poorer executive function (shifting) but not retrospective memory. This study is among the first to examine the association between objectively measured sleep and prospective memory in older adults. Furthermore, this study is novel in suggesting sleep disruption might contribute to age-related prospective memory deficits; perhaps, with implications for cognitive aging more broadly. Our results suggest that there may be opportunities to prevent prospective memory decline by treating sleep problems.     

The impact of sleep quality,fatigue and safety climate on the perceptions of accident risk among seafarers

IntroductionSeafaring is an extremely demanding profession that takes place in one of the most dangerous work environments possible. The unpredictable and demanding working conditions foster a high potential for risks and accidents.ObjectivesTo examine how sleep quality, fatigue and safety climate combine to influence perceptions of risk among seafarers.MethodParticipants were 151 seafarers working in the deck or machine departments on board 11 ships belonging to a Norwegian company. Questionnaires were administered at two different time points, approximately one week apart.ResultsPerceptions of risk of personal injuries and ship accidents increase when seafarers are fatigued. We also found that fatigue is related to poor sleep quality and that safety climate predicted both sleep quality and fatigue one week later.ConclusionsThe findings point to the importance for maritime organizations to be cognizant of the causes and consequences of fatigue among their employees, and that that policies and prioritizations are being perceived and interpreted by seafarers and may influence their sleep quality and vigilance when working at sea.     

A two-week monitoring of self-reported arousal, worry and attribution among persons with annoyance attributed to electrical equipment and smells

Non-patients attributing annoyance to either smells (smell annoyed; SA, n= 29) or electrical equipment (electrically annoyed; EA, n= 17), or both (generally annoyed; GA, n= 38), were monitored for 2 weeks through daily self-ratings of arousal (stress), sleep disturbances, health complaints, worry about hypersensitivity reactions, avoidance behaviors, and attributions of health complaints to electrical equipment and smells. In parallel, a demographically matched reference group was followed (n= 56). GA persons reported higher arousal (stress), more subjective health complaints, and more sleep disturbances than the other groups. About 60% in the GA and EA groups reported intentional avoidance behavior, compared to 31% in the SA group and 2% of the referents. Worry and attribution to environmental factors was also more frequent among GA persons than in the other groups. Thus, even at sub-clinical levels, environmental annoyance generalized to several triggers seems to be associated with behaviors commonly observed among patients with idiopathic environmental intolerance.     

Examination of a multi-factorial model of body-related experiences during pregnancy: the relationships among physical symptoms, sleep quality, depression, self-esteem, and negative body attitudes

The aim of this cross-sectional study was to investigate relationships among women's body attitudes, physical symptoms, self-esteem, depression, and sleep quality during pregnancy. Pregnant women (N = 215) at 15–25 weeks gestation completed a questionnaire including four body image subscales assessing self-reported feeling fat, attractiveness, strength/fitness, and salience of weight and shape. Women reported on 29 pregnancy-related physical complaints, and completed the Beck Depression Inventory, Rosenberg Self-esteem Scale, and Pittsburgh Sleep Quality Index. In regressions, controlling for retrospective reports of body image, more frequent and intense physical symptoms were related to viewing the self as less strong/fit, and to poorer sleep quality and more depressive symptoms. In a multi-factorial model extending previous research, paths were found from sleep quality to depressive symptoms to self-esteem; self-esteem was found to be a mediator associated with lower scores on feeling fat and salience of weight and shape, and on higher perceived attractiveness.     

Sleep and psychopathology

This article examines the relationship between sleep disturbance and psychopathology. Epidemiological, cross-sectional, and longitudinal data suggest a high rate of comorbidity between sleep disturbance and psychopathology, particularly between insomnia, anxiety, and depression. Between 50% and 80% of psychiatric patients complain of sleep disturbances during the acute phase of their illness. Conversely, among treatment-seeking individuals with a primary complaint of insomnia and randomly selected community samples, approximately one third display a concurrent psychopathology, one third exhibit psychological symptoms that do not necessarily exceed the threshold for a psychiatric disorder, and another third present insomnia as a functionally autonomous disorder. There is a positive relationship between severity of sleep disturbances and concurrent psychopathology, but unequivocal evidence of a cause-and-effect relationship is still lacking. However, longitudinal data suggest that anxiety and stressful life events often precede acute sleep difficulties, whereas persistent insomnia may be a risk factor for subsequent development of depression. Implications for the prevention and treatment of coexisting sleep disturbance and psychopathology are discussed.     

Associations between mother-infant bed-sharing practices and infant affect and behavior during the still-face paradigm

Parents in the United States increasingly report bed-sharing with their infants (i.e., sleeping on a shared sleep surface), but the relationship between bed-sharing and child socioemotional outcomes are not well understood. The current study examines the links between mother-infant bed-sharing at 3 months and infant affect and behavior during a dyadic challenge task at 6 months. Further, we examine nighttime mother-infant contact at 3 months as a possible mechanism that may mediate linkages between bed-sharing and infant outcomes. Using observational data from a sample of 63 mother-infant dyads, we found that infants who bed-shared for any proportion of the observation period at 3 months displayed significantly more self-regulatory behaviors during the still-face episode of the Still-Face Paradigm (SFP) at 6 months, compared to non-bed-sharing infants. Also, infants of mothers who bed-shared for the entire observation period displayed significantly less negativity during the reunion episode than non-bed-sharing infants. There was no evidence that the relations between mother-infant bed-sharing practices and infant affect and behavior during the SFP were mediated through nighttime mother-infant contact. Results suggest that infant regulation at 6 months postpartum may vary based on early nighttime experiences, with bed-sharing potentially promoting more positive and well-regulated behavior during dyadic interaction.     

Dream engineering: Simulating worlds through sensory stimulation

We explore the application of a wide range of sensory stimulation technologies to the area of sleep and dream engineering. We begin by emphasizing the causal role of the body in dream generation, and describe a circuitry between the sleeping body and the dreaming mind. We suggest that nearly any sensory stimuli has potential for modulating experience in sleep. Considering other areas that might afford tools for engineering sensory content in simulated worlds, we turn to Virtual Reality (VR). We outline a collection of relevant VR technologies, including devices engineered to stimulate haptic, temperature, vestibular, olfactory, and auditory sensations. We believe these technologies, which have been developed for high mobility and low cost, can be translated to the field of dream engineering. We close by discussing possible future directions in this field and the ethics of a world in which targeted dream direction and sleep manipulation are feasible.