Neuropsychiatric studies of sleep and 24-hour activity rhythms

__Abstract__ In Nederland ervaart tot 40% van de bevolking slaapklachten, regelmatig staan deze problemen in verband met andere gezondheidsklachten. Slaap is een wisselwerking tussen twee processen. Als eerste is er de slaapbehoefte, deze wordt grotendeels bepaald door hoe lang iemand wakker is. Als tweede is er het circadiaans ritme, dit is het ongeveer 24-uur durende dag-nacht ritme van het lichaam. In deze studie hebben wij onderzocht hoe verstoringen in slaap en het 24-uurs ritme van beweging samenhangen met de lichamelijke en geestelijke gezondheid in het ERGO-onderzoek. Het onderzoek laat zien dat naarmate mensen ouder worden ze een stabieler 24-uurs ritme hebben, maar het ritme ook meer gefragmenteerd wordt, dat wil zeggen dat het vermogen om langer in een actieve of non-actieve staat te blijven beperkt is. Echter, uit ons onderzoek blijkt ook dat zowel onstabiele als meer gefragmenteerde ritmes de levensduur verkorten. Waarschijnlijk reflecteren verstoringen in het 24-uurs ritme veranderingen in de biologische klok, mogelijk zijn ze een indicatie voor een slechte gezondheid. Het hebben van stabiele ritmes op oudere leeftijd zou, bewust of onbewust, een strategie kunnen zijn voor het omgaan met een slechtere gezondheid. Ook de geestelijke gezondheid hangt samen met veranderingen in slaap en 24-uurs ritmes. De resultaten demonstreren dat verstoringen in de slaap vooral in verband staan met slechtere prestaties op geheugen- en taaltaken, terwijl verstoringen in het 24-uurs ritme vooral in verband staat met een verminderde snelheid en een verminderde uitvoer van complexere taken. Ook bleek uit het onderzoek dat 24-uurs ritmes verstoord zijn in personen met depressie- en angstklachten. Daarentegen werden bij mensen met klachten van depressie geen veranderingen gezien in de globale kenmerken van slaap, zoals de objectief gemeten slaapduur, de tijd die het kost om in slaap te vallen en de ernst van slaap apneu. Specifieke kenmerken van de slaap, zoals de hoeveelheid snelle oogbewegingen in de REM-slaap, waren echter wel veranderd in personen die depressie rapporteren. Ook hoe mensen hun slaapkwaliteit ervaren is afhankelijk van de hoeveelheid depressie- en angstklachten. Als laatste bestudeerden we slaap en het 24-uurs ritme in relatie tot het functioneren van de hypothalamus-hypofyse-bijnier as, dit is een systeem in de hersenen wat onder andere van belang is voor stress. De resultaten lieten zien dat dit systeem gerelateerd was aan zowel slaapduur, een verstoord ritme e

24-h Activity Rhythms and Health in Older Adults

__Purpose of Review:__ Circadian rhythms, including 24-h activity rhythms, change with age. Disturbances in these 24-h activity rhythms at older age have also been implied in various diseases. This review evaluates recent findings on 24-h activity rhythms and disease in older adults. __Recent Findings:__ Growing evidence supports that 24-h activity rhythm disturbances at older age are related to the presence and/or progression of disease. Longitudinal and genetic work even suggests a potential causal contribution of disturbed 24-h activity rhythms to disease development. Interventional studies targeting circadian and 24-h activity rhythms demonstrate that 24-h rhythmicity can be improved, but the effect of improving 24-h rhythmicity on disease risk or progression remains to be shown. __Summary:__ Increasing evidence suggests that 24-h activity rhythms are involved in age-related diseases. Further studies are needed to assess causality, underlying mechanisms, and the effects of treating disturbed 24-h activity rhythms on age-related disease

Sleep disturbance and intrusive memories after presenting to the emergency department following a traumatic motor vehicle accident: an exploratory analysis

Background: Sleep disturbances are common after traumatic events and have been hypothesized to be a risk factor in the development of psychopathology such as that associated with posttraumatic stress disorder (PTSD). Objective: To assess the association between intrusive memories, a core clinical feature of PTSD, and self-reported sleep disturbance shortly after experiencing or witnessing a motor vehicle accident, and whether a brief behavioural intervention (trauma reminder cue and Tetris gameplay) reduced sleep disturbance post-trauma. Method: The exploratory analyses included 71 participants (mean age 39.66, standard deviation 16.32; 37 women, 52.1%) enrolled in a previously published proof-of-concept randomized controlled trial. Participants were recruited from the emergency department after experiencing or witnessing a traumatic motor vehicle accident. Intrusive memories were assessed with a daily paper-and-pen diary for one week post-trauma, and sleep disturbances with three questions from the Impact of Event Scale-Revised assessing problems initiating sleep, problems maintaining sleep and dreams about the event at one week and one month post-trauma. Missing data were imputed 15 times. Results: The total number of intrusive memories during the first week post-trauma suggested weak to moderate pooled intercorrelations with problems initiating and maintaining sleep. An ordinal regression using imputed data suggested that the intervention had no effect on sleep disturbances, while completers only analyses suggested an improvement in problems maintaining sleep at one week. Conclusions: This exploratory study suggested that experiencing early intrusive memories is related to sleep disturbances. Sleep disturbance might be a particularly important construct to assess in studies involving intrusive memories post-trauma

Sleep and 24-h activity rhythms in relation to cortisol change after a very low-dose of dexamethasone

The hypothalamic-pituitary-adrenal (HPA) axis plays an important role in sleep. Nevertheless, the association of sleep and its 24-h organization with negative feedback control of the HPA axis has received limited attention in population-based studies. We explored this association in 493 mid

Associations of the 24-h activity rhythm and sleep with cognition: A population-based study of middle-aged and elderly persons

Background: Cognitive functioning changes with age, sleep, and the circadian rhythm. We investigated whether these factors are independently associated with different cognitive domains assessed in middle-aged and elderly persons. Methods: In 1723 middle-aged and elderly persons (age 62 ± 9.4 years, mean ± standard deviation, SD) of the Rotterdam Study, we collected actigraphy recordings of on average 138 h. Actigraphy was used to quantify 24-h rhythms by calculating the stability of the rhythm over days and the fragmentation of the rhythm. Sleep parameters including total sleep time, sleep-onset latency, and wake after sleep onset were also estimated from actigraphy. Cognitive functioning was assessed with the word learning test (WLT), word fluency test (WFT), letter digit substitution task (LDST), and Stroop color word test (Stroop). Results: Persons with less stable 24-h rhythms performed worse on the LDST (. B = 0.42 per SD increase, p = 0.004) and the Stroop interference trial (. B = -1.04 per SD increase, p = 0.003) after full adjustment. Similarly, persons with more fragmented rhythms performed worse on the LDST (. B = -0.47 per SD increase, p = 0.002) and the Stroop (.

Sleep, 24-h activity rhythms, and plasma markers of neurodegenerative disease

Sleep and 24-h activity rhythm disturbances are associated with development of neurodegenerative diseases and related pathophysiological processes in the brain. We determined the cross-sectional relation of sleep and 24-h activity rhythm disturbances with plasma-based biomarkers that might signal neurodegenerative disease, in 4712 middle-aged and elderly non-demented persons. Sleep and a

Sleep and resting-state functional magnetic resonance imaging connectivity in middle-aged adults and the elderly: A population-based study

Sleep problems increase with ageing. Increasing evidence suggests that sleep problems are not only a consequence of age-related processes, but may independently contribute to developing vascular or neurodegenerative brain disease. Yet, it remains unclear what mechanisms underlie the impact sleep problems may have on brain health in the general middle-aged and elderly population. Here, we studied sleep's relation to brain functioning in 621 participants (median age 62 years, 55% women) from the population-based Rotterdam Study. We investigated cross-sectional associations of polysomnographic and subjectively measured aspects of sleep with intrinsic neural activity measured with resting-state functional magnetic resonance imaging on a different day. We investigated both functional connectivity between regions and brain activity (blood-oxygen-level-dependent signal amplitude) within regions, hierarchically towards smaller topographical levels. We found that longer polysomnographic total sleep time is associated with lower blood-oxygen-level-dependent signal amplitude in (pre)frontal regions. No objective or subjective sleep parameters were associated with functional connectivity between or within resting-state networks. The findings may indicate a pathway through which sleep, in a ‘real-life’ population setting, impacts brain activity or regional brain activity determines t