Articles de revues : « Rest-activity circadian rhythm »

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Calogiuri, Giovanna, Andi Weydahl et Franca Carandente. « Methodological Issues for Studying the Rest–Activity Cycle and Sleep Disturbances ». Biological Research For Nursing 15, n^o 1 (5 août 2011) : 5–12. http://dx.doi.org/10.1177/1099800411416224.

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Shift work schedules, intensive physical exercise late in the day, psychological stress, or a busy lifestyle might induce disorders of the circadian structure, which can affect health on both the physiological and neurobehavioral levels. Rest–activity rhythm is strongly connected with an organism’s circadian structure, and irregular sleep–wake patterns can lead to a disruption of entrainment, resulting in physiological and neurobehavioral dysfunction. Shift nurses are often subject to disturbances in the quality and duration of their sleep, raising the possibility of negative impacts on their health and their patients' safety. Researchers have used actigraphy in a number of studies to assess sleep patterns. Because of the close connection between sleep and circadian structure, it may be useful to extend the evaluation of actigraphy data to the analysis of the rest–activity rhythm with rhythmometric procedures to provide a better understanding of possible sleep disorders in relation to entrainment. Actigraphy is an easy and reliable way to study these rhythms and identify possible circadian-rhythm disorders. In this article, the authors discuss methodological issues concerning the evaluation of the rest–activity rhythm, with a focus on actigraphy.

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Gander, P. H., R. Lydic, H. E. Albers et M. C. Moore-Ede. « Forced internal desynchronization between circadian temperature and activity rhythms in squirrel monkeys ». American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 248, n^o 5 (1 mai 1985) : R567—R572. http://dx.doi.org/10.1152/ajpregu.1985.248.5.r567.

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In an attempt to force internal desynchronization between the rest-activity rhythm and the body temperature rhythm of the squirrel monkey (Saimiri sciureus), five animals were studied in a 14:14 light-dark cycle. In four animals a 28-h spectral component was found to predominate in the rest-activity rhythm, whereas an unentrained circadian component (tau = 25.9 +/- 0.4 h) predominated in the body temperature rhythm. Plots of the cycle-by-cycle acrophases of the two rhythms confirm that they desynchronize, due to the failure of the temperature rhythm to entrain to the light-dark cycle. These data from intact animals provide further support for the hypothesis that the squirrel monkey circadian timing system has at least two pacemakers. A rhythm for which the supra-chiasmatic nuclei (SCN) have previously been shown to be essential (rest-activity) simultaneously exhibited a different period from a rhythm (body temperature) that has been shown to persist after destruction of the SCN.

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Arzola-Rodríguez, Jesús José. « Sueño y ritmos circadianos en supervivientes de falla respiratoria aguda ». Kompass Neumología 3, n^o 1 (2021) : 14–15. http://dx.doi.org/10.1159/000513799.

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Background: Little is known about sleep and circadian rhythms in survivors of acute respiratory failure (ARF) after hospital discharge. Objectives: To examine sleep and rest-activity circadian rhythms in ARF survivors 3 months after hospital discharge, and to compare them with a community-dwelling population. Methods: Sleep diary, actigraphy data, and insomnia symptoms were collected in a pilot study of 14 ARF survivors. Rest-activity circadian rhythms were assessed with wrist actigraphy and sleep diary for 9 days, and were analyzed by cosinor and non-parametric circadian rhythm analysis. Results: All participants had remarkable actigraphic sleep fragmentation, 71.5% had subclinical or clinical insomnia symptoms. Compared to community-dwelling adults, this cohort had less stable rest-activity circadian rhythms (p < 0.001), and weaker circadian strength (p < 0.001). Conclusion: Insomnia and circadian disruption were common in ARF survivors. Sleep improvement and circadian rhythm regularity may be a promising approach to improve quality of life and daytime function after ARF.

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Slyepchenko, Anastasiya, Olivia R. Allega, Xiamin Leng, Luciano Minuzzi, Maha M. Eltayebani, Matthew Skelly, Roberto B. Sassi, Claudio N. Soares, Sidney H. Kennedy et Benicio N. Frey. « Association of functioning and quality of life with objective and subjective measures of sleep and biological rhythms in major depressive and bipolar disorder ». Australian & ; New Zealand Journal of Psychiatry 53, n^o 7 (13 février 2019) : 683–96. http://dx.doi.org/10.1177/0004867419829228.

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Objective: Disruptions in biological rhythms and sleep are a core aspect of mood disorders, with sleep and rhythm changes frequently occurring prior to and during mood episodes. Wrist-worn actigraphs are increasingly utilized to measure ambulatory activity rhythm and sleep patterns. Methods: A comprehensive study using subjective and objective measures of sleep and biological rhythms was conducted in 111 participants (40 healthy volunteers [HC], 38 with major depressive disorder [MDD] and 33 with bipolar disorder [BD]). Participants completed 15-day actigraphy and first-morning urine samples to measure 6-sulfatoxymelatonin levels. Sleep and biological rhythm questionnaires were administered: Biological Rhythms Interview of Assessment in Neuropsychiatry (BRIAN), Munich Chronotype Questionnaire (MCTQ), Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS). Actigraph data were analyzed for sleep and daily activity rhythms, light exposure and likelihood of transitioning between rest and activity states. Results: Mood groups had worse subjective sleep quality (PSQI) and biological rhythm disruption (BRIAN) and higher objective mean nighttime activity than controls. Participants with BD had longer total sleep time, higher circadian quotient and lower 6-sulfatoxymelatonin levels than HC group. The MDD group had longer sleep onset latency and higher daytime probability of transitioning from rest to activity than HCs. Mood groups displayed later mean timing of light exposure. Multiple linear regression analysis with BRIAN scores, circadian quotient, mean nighttime activity during rest and daytime probability of transitioning from activity to rest explained 43% of variance in quality-of-life scores. BRIAN scores, total sleep time and probability of transitioning from activity to rest explained 52% of variance in functioning (all p < 0.05). Conclusions: Disruption in biological rhythms is associated with poorer functioning and quality of life in bipolar and MDD. Investigating biological rhythms and sleep using actigraphy variables, urinary 6-sulfatoxymelatonin and subjective measures provide evidence of widespread sleep and circadian system disruptions in mood disorders.

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Kim, Minjee, Kathryn Reid, Matthew Maas, Thanh-Huyen Vu, Rosemary Braun, Martha Daviglus et Phyllis Zee. « 164 Greater Light Exposure Is Associated with More Robust Rest-Activity Rhythms in Community-Dwelling Older Adults ». Sleep 44, Supplement_2 (1 mai 2021) : A67. http://dx.doi.org/10.1093/sleep/zsab072.163.

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Abstract Introduction Disrupted circadian rest-activity rhythms in older adults have been associated with an increased risk of cognitive decline and mortality. While light is one of the most potent synchronizing agents for the human circadian system, little is known about how light may influence rest-activity rhythms in older adults. We aimed to investigate the relationship between the amount of light exposure and rest-activity rhythm parameters using actigraphy data from a large cohort study. Methods 553 community-dwelling older adults (aged 72±5, 142 (25.5%) female) from the Chicago Healthy Aging Study cohort underwent recording of activity and ambient light exposure for a minimum of five 24-hour periods, using Actiwatch-L (Phillips Respironics). The average recording duration was 6.7±0.5 days. An extension to the traditional cosine model was used to compute circadian rest-activity rhythm parameters, including the amplitude (a measure of strength), the goodness of fit (pseudo F statistic; a measure of robustness), and acrophase (timing of peak activity). Light exposure was measured by time spent above light thresholds of 100, 200, 500, and 1000 lux per day (TAT100, TAT200, TAT500, TAT1000, respectively). Bivariate associations between rhythm parameters and TAT values were examined with Spearman’s correlation coefficients. Variables that met a significant threshold (p<0.05) were entered into multivariable models to adjust for potential confounders including age, sex, race, and season. Results Robustness of the rest-activity rhythm, measured by extended cosine pseudo-F statistics, was associated with TAT100 (partial Spearman’s correlation coefficient 0.12, p=0.008), TAT200 (coefficient 0.13, p=0.03), TAT500 (coefficient 0.16, p<0.001), and TAT 1000 (coefficient 0.18, p<0.001). TAT100/200/500/1000 were also associated with the strength of the rest-activity rhythm, measured by amplitude of the extended cosine fit (partial Spearman’s correlation coefficient vs. TAT100: 0.12, p=0.006, TAT200: 0.14, p=0.002, TAT500: 0.16, p<0.001, TAT1000: 0.18, p<0.001), after adjusting for age, sex, race, and season. Conclusion Across the seasons, greater daily light exposure is associated with more robust circadian rest-activity rhythm in community-dwelling older adults. Whether the enhancement of light exposure can improve the strength and robustness of rest-activity rhythm needs to be tested with future intervention studies. Support (if any):

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Fujioka, Haruna, Masato S. Abe, Taro Fuchikawa, Kazuki Tsuji, Masakazu Shimada et Yasukazu Okada. « Ant circadian activity associated with brood care type ». Biology Letters 13, n^o 2 (février 2017) : 20160743. http://dx.doi.org/10.1098/rsbl.2016.0743.

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In group-living animals, social interactions influence various traits including circadian activity. Maternal care, in particular, can have a strong effect on the circadian activity of parents or nurses across taxa. In social insects, nest-mates are known to have diverse activity rhythms; however, what kind of social environment is crucial in shaping an individual's rhythm is largely unknown. Here, we show that the focal brood types being taken care of (i.e. egg, larva and pupa) have significant effects on individual activity/rest rhythm, using the monomorphic ant Diacamma (putative species indicum ). When isolated from a colony, nurses exhibited a clear circadian rhythm. However, when paired with eggs or larvae, they exhibited around-the-clock activity with no apparent rhythm. In contrast, a clear activity rhythm emerged when nurses were paired with a pupa, requiring little care. Such brood-type-specific changes in circadian activity are considered to arise from the difference in caretaking demands. Our finding may contribute to the understanding of the organization of a colony in the context of behavioural variability under different microenvironments.

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van Someren, Eus J. W., Eveline E. O. Hagebeuk, Cees Lijzenga, Philip Scheltens, Sophie E. J. A. de Rooij, Cees Jonker, Anne-Margriet Pot, Majid Mirmiran et Dick F. Swaab. « Circadian rest—activity rhythm disturbances in alzheimer's disease ». Biological Psychiatry 40, n^o 4 (août 1996) : 259–70. http://dx.doi.org/10.1016/0006-3223(95)00370-3.

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Giannetto, C., F. Fazio, A. Assenza, G. Caola, P. Pennisi et G. Piccione. « Circadian rhythms of redox states and total locomotor activity in dairy cattle ». Czech Journal of Animal Science 55, No. 5 (17 mai 2010) : 183–89. http://dx.doi.org/10.17221/306/2009-cjas.

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We want to study the circadian rhythm of dROMs and anti-oxidative power in dairy cattle during dry period and the possible involvement of the circadian organization of rest/activity cycles in the fluctuation of redox state. For this purpose we recorded TLA in five clinically healthy Bruna Italian dairy cattle by means of an actigraphy-based data logger, Actiwatch-Mini®. Blood samples were collected every 3 hours over a 48-hour period for the assessment of free radicals (dROMs) and the antioxidant power: antioxidant barrier (Oxy-ads) and thiol-antioxidant barrier (SHp). All animals were in the same productive period (dry) and they were housed in the same stable under natural photoperiod and ambient temperature. One-way repeated measure ANOVA was used to determine a statistical significant effect of time on the studied parameters. A trigonometric statistical model was applied to characterize the main rhythmic parameters according to the single cosinor procedure. A significant effect of time on all studied parameters was observed. They showed a diurnal acrophase and different degrees of robustness of rhythms. In conclusion, we can claim that there is a synergism between the dROM circadian rhythm and the circadian rhythm of anti-oxidative power. These rhythms do not have any implication for the issue of causation with the TLA circadian rhythms.

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Lee, Jung Hyun, Eunsoo Moon, Jeonghyun Park, Chi Eun Oh, Yoo Rha Hong et Min Yoon. « Optimization of Analysis of Circadian Rest-Activity Rhythm Using Cosinor Analysis in Mice ». Psychiatry Investigation 19, n^o 5 (25 mai 2022) : 380–85. http://dx.doi.org/10.30773/pi.2021.0395.

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Objective Data processing in analysis of circadian rhythm was performed in various ways. However, there was a lack of evidence for the optimal analysis of circadian rest-activity rhythm. Therefore, we aimed to perform mathematical simulations of data processing to investigate proper evidence for the optimal analysis of circadian rest-activity rhythm.Methods Locomotor activities of 20 ICR male mice were measured by infrared motion detectors. The data of locomotor activities was processed using data summation, data average, and data moving average methods for cosinor analysis. Circadian indices were estimated according to time block, respectively. Also, statistical F and p-values were calculated by zero-amplitude test.Results The data moving average result showed well-fitted cosine curves independent of data processing time. Meanwhile, the amplitude, MESOR, and acrophase were properly estimated within 800 seconds in data summation and data average methods.Conclusion These findings suggest that data moving average would be an optimal method for data processing in a cosinor analysis and data average within 800-second data processing time might be adaptable. The results of this study can be helpful to analyze circadian restactivity rhythms and integrate the results of the studies using different data processing methods.

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Dispersyn, Garance, Laure Pain et Yvan Touitou. « Circadian Disruption of Body Core Temperature and Rest–Activity Rhythms after General (Propofol) Anesthesia in Rats ». Anesthesiology 110, n^o 6 (1 juin 2009) : 1305–15. http://dx.doi.org/10.1097/aln.0b013e3181a10225.

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Background General anesthesia is commonly associated with sleep disorders, fatigue, drowsiness, and mood alterations in patients. The authors examined whether general (propofol) anesthesia can impact the circadian temporal structure by disturbing circadian rest-activity and body temperature rhythms under normal light-dark conditions (light-dark 12:12 h) in rats. Methods A group of rats was anesthetized with propofol, and another was injected with 10% Intralipid, which was used as a control lipidic solution. The authors examined six groups of rats according to the Zeitgeber time of intraperitoneal administration (ZT6, ZT10, ZT16) and the substance injected (propofol or Intralipid). Results On the day after anesthesia, propofol induced a significant 60- to 80-min phase advance of both rest-activity and body temperature rhythms. A significant 45- to 60-min phase advance of body temperature and a significant 20-min phase advance of rest-activity were still observed on the second day after anesthesia. The amplitudes of both rest-activity and body temperature rhythms were decreased on the first and second days after anesthesia. The 24-h mean rest-activity rhythm was decreased on the day after anesthesia, whereas the 24-h mean body temperature rhythm was not modified. Conclusion The results demonstrate the disturbing effects of propofol anesthesia on the circadian time structure in rats under normal light conditions.

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Calogiuri, Giovanna, Andi Weydahl et Eliana Roveda. « Effects of Sleep Loss and Strenuous Physical Activity on the Rest–Activity Circadian Rhythm ». Biological Research For Nursing 13, n^o 4 (30 décembre 2010) : 409–18. http://dx.doi.org/10.1177/1099800410392021.

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Objective. Rest–activity circadian rhythm is strongly linked to an organism’s entrainment. Sleep loss and prolonged fatigue could affect the circadian system, inducing neurobehavioral deficits. The Finnmarksløpet is Europe’s longest dogsled race. In this competition, lasting up to 7 days, participants (mushers) are physically active most of the time, having little and fragmented rest. Therefore, the race provides an opportunity to investigate the effects of prolonged fatigue and sleep loss. Methods. Ten mushers, participating in the 500 km and 1,000 km categories, underwent continuous actigraph monitoring (5 days) before and after the race. During the competition, heart rate (HR) was recorded by an HR monitor. Results. There was a reduction in the average activity values during the 24-hr cycle after the race. Although there were signs of a forward phase shift, these were weak and unstable. Nonparametric circadian rhythm analysis (NPCRA) showed reductions in interdaily stability (IS) and relative amplitude (RA). 1,000 km mushers also showed sleep disturbances. Conclusion. A period of 3 days of little and fragmented sleep (3–4 hr of total rest per day), in which subjects were engaged in a prolonged physical effort, was enough to significantly affect the rest–activity rhythm. A longer period (5 days) in such a condition induced even more accentuated alterations, with a disturbance in nocturnal sleep. Disrupted sleep is common among hospitalized patients and those working long shifts. This study demonstrates changes in the structure of the rest–activity circadian rhythm that can result and may suggest opportunities for intervention.

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Nishihara, Kyoko, Shigeko Horiuchi, Hiromi Eto et Sunao Uchida. « The development of infants' circadian rest–activity rhythm and mothers' rhythm ». Physiology & ; Behavior 77, n^o 1 (septembre 2002) : 91–98. http://dx.doi.org/10.1016/s0031-9384(02)00846-6.

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Fujioka, Haruna, Masato S. Abe et Yasukazu Okada. « Individual Ants Do Not Show Activity-Rest Rhythms in Nest Conditions ». Journal of Biological Rhythms 36, n^o 3 (5 avril 2021) : 297–310. http://dx.doi.org/10.1177/07487304211002934.

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Circadian rhythms, which respond to the day-night cycle on the earth, arise from the endogenous timekeeping system within organisms, called the “biological clock.” For accurate circadian rhythms, daily fluctuations in light and temperature are considered one of the important time cues. In social insects, both abiotic and biotic factors (i.e., social interactions) play a significant role in activity-rest rhythm regulation. However, it is challenging to monitor individual activity-rest rhythms in a colony because of the large group size and small body size. Therefore, it is unclear whether individuals in a colony exhibit activity-rest rhythms and how social interactions regulate their activity-rest rhythms in the colony. This study developed an image-based tracking system using 2D barcodes for Diacamma cf. indicum from Japan (a monomorphic ant) and measured the locomotor activities of all colony members under laboratory colony conditions. We also investigated the effect of broods on activity-rest rhythms by removing all broods under colony conditions. Activity-rest rhythms appeared only in isolated ants, not under colony conditions. In addition, workers showed arrhythmic activities after brood removal. These results suggested that a mixture of social interactions, and not light and temperature, induces the loss of activity-rest rhythms. These results contribute to the knowledge of a diverse pattern of circadian activity rhythms in social insects.

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Minaeva, O., E. Schat, E. Ceulemans, Y. Kunkels, A. Smit, M. Wichers, S. Booij et H. Riese. « Individual-specific changes in circadian rest-activity rhythm and sleep in symptom-free patients tapering their antidepressant medication ». European Psychiatry 65, S1 (juin 2022) : S679. http://dx.doi.org/10.1192/j.eurpsy.2022.1747.

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Introduction Group-level studies showed cross-sectional and prospective between-person associations between circadian rest-activity rhythms (RAR), physical activity (PA), sleep, and depressive symptoms. However, whether these associations replicate at the within-person level remains unclear. Therefore, it is clinically relevant to investigate these associations within persons and study whether changes in depressive symptoms are related to changes in circadian rhythm and sleep variables. Objectives To identify changes in circadian rhythm elements in proximity to a transition in depressive symptoms, whether changes are less frequent in individuals without compared to those with transitions, and whether there are individual differences in the direction of change of circadian rhythm variables. Methods Data of remitted individuals tapering antidepressants were used: 12 with and 14 without a transition in depressive symptoms. RAR, PA, and sleep variables were calculated as predictors from four months of actigraphy data. Transitions in depressive symptoms were based on weekly SCL-90 scores and evaluation interviews. Kernel Change Point analyses were used to detect change points (CPs) and CP timing in circadian rhythm variables for each individual separately. Results In 67% of individuals with depressive symptoms transitions, CPs were identified in proximity to symptom transitions. CPs were detected less frequently in the no-transition group with 7 CPs in 14 individuals, compared to transition groups with 10 CPs in 12 individuals. For several RAR and sleep variables, consistent changes were detected in expected directions. Conclusions Circadian rhythm variables provide potentially clinically relevant information although their patterns around transitions are highly person-specific. Future research is needed to disentangle which variables are predictive for which patients. Disclosure No significant relationships.

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McKinnon, Leela, David R. Samson, Charles L. Nunn, Amanda Rowlands, Katrina G. Salvante et Pablo A. Nepomnaschy. « Technological infrastructure, sleep, and rest-activity patterns in a Kaqchikel Maya community ». PLOS ONE 17, n^o 11 (16 novembre 2022) : e0277416. http://dx.doi.org/10.1371/journal.pone.0277416.

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Sleep duration, quality, and rest-activity pattern—a measure for inferring circadian rhythm—are influenced by multiple factors including access to electricity. Recent findings suggest that the safety and comfort afforded by technology may improve sleep but negatively impact rest-activity stability. According to the circadian entrainment hypothesis, increased access to electric lighting should lead to weaker and less uniform circadian rhythms, measured by stability of rest-activity patterns. Here, we investigate sleep in a Maya community in Guatemala who are in a transitional stage of industrialization. We predicted that (i) sleep will be shorter and less efficient in this population than in industrial settings, and that (ii) rest-activity patterns will be weaker and less stable than in contexts with greater exposure to the natural environment and stronger and more stable than in settings more buffered by technologic infrastructure. Our results were mixed. Compared to more industrialized settings, in our study population sleep was 4.87% less efficient (78.39% vs 83.26%). We found no significant difference in sleep duration. Rest-activity patterns were more uniform and less variable than in industrial settings (interdaily stability = 0.58 vs 0.43; intradaily variability = 0.53 vs 0.60). Our results suggest that industrialization does not inherently reduce characteristics of sleep quality; instead, the safety and comfort afforded by technological development may improve sleep, and an intermediate degree of environmental exposure and technological buffering may support circadian rhythm strength and stability.

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Jean-Louis, Girardin, Ferdinand Zizi, Hans Von Gizycki et Harvey Taub. « Effects of Melatonin in Two Individuals with Alzheimer's Disease ». Perceptual and Motor Skills 87, n^o 1 (août 1998) : 331–39. http://dx.doi.org/10.2466/pms.1998.87.1.331.

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Dementia has been associated with circadian rhythm disturbances expressed in several dimensions including body temperature, hormonal concentrations, sleep and wakefulness patterns, and rest-activity cycles. These disturbances may be the result of a dampening in the amplitude of the circadian rhythm. One of the symptoms associated with the aging process has been a decline in the amplitude of the melatonin rhythm. Here, the results of melatonin administration to two patients with Alzheimer's disease are presented. Melatonin administration enhanced and stabilized the circadian rest-activity rhythm in one of the patients along with some reduction of daytime sleepiness and an improvement in mood. The other patient, who was characterized by less cognitive impairment, showed no significant changes associated with melatonin ingestion. Interestingly, the acrophase of rest-activity was delayed for about one hour in both patients. These results suggest that melatonin may have beneficial effects in some patients with Alzheimer's disease

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Yesavage, Jerome A., Leah Friedman, Helena C. Kraemer, Art Noda, Deryl Wicks, Donald L. Bliwise, Javaid Sheikh, Jared Tinklenberg et Vincent Zarcone. « A Follow-Up Study of Actigraphic Measures in Home-Residing Alzheimer's Disease Patients ». Journal of Geriatric Psychiatry and Neurology 11, n^o 1 (avril 1998) : 7–10. http://dx.doi.org/10.1177/089198879801100103.

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This article reports cross-sectional and follow-up data with actigraphic measures of nocturnal sleep and rest/activity in 61 Alzheimer's disease (AD) patients as well as the relation of actigraphic measures to levels of behavioral disturbance across different stages of the disease. Over the course of approximately 1.5 years' follow-up, patients showed significant deterioration of nocturnal sleep parameters, but no significant change in rest/activity circadian rhythm parameters. There were also significant correlations among nocturnal sleep, rest/activity circadian rhythm, and behavioral disturbance measures, but only in relatively early stages of AD. It is argued that study of nocturnal sleep and circadian rhythm in relation to behavioral disturbance in AD requires longitudinal data and analyses that take into account the stage of disease at which patients are assessed.

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Nunes, Deuzilane Muniz, Bruno S. B. Gonçalves, Carina Aparecida Tardelli Peixoto, Veralice Meireles Sales De Bruin, Fernando Mazzilli Louzada et Pedro Felipe Carvalhedo De Bruin. « Circadian rest-activity rhythm in chronic obstructive pulmonary disease ». Chronobiology International 34, n^o 9 (20 octobre 2017) : 1315–19. http://dx.doi.org/10.1080/07420528.2017.1352594.

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Filardi, Marco, Fabio Pizza, Oliviero Bruni, Vincenzo Natale et Giuseppe Plazzi. « Circadian Rest-Activity Rhythm in Pediatric Type 1 Narcolepsy ». Sleep 39, n^o 6 (1 juin 2016) : 1241–47. http://dx.doi.org/10.5665/sleep.5842.

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Robinson, Edward L., et Charles A. Fuller. « Endogenous thermoregulatory rhythms of squirrel monkeys in thermoneutrality and cold ». American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 276, n^o 5 (1 mai 1999) : R1397—R1407. http://dx.doi.org/10.1152/ajpregu.1999.276.5.r1397.

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Whole body heat production (HP) and heat loss (HL) were examined to determine if the free-running circadian rhythm in body temperature (Tb) results from coordinated changes in HP and HL rhythms in thermoneutrality (27°C) as well as mild cold (17°C). Squirrel monkey metabolism ( n = 6) was monitored by both indirect and direct calorimetry, with telemetered measurement of Tb and activity. Feeding was also measured. Rhythms of HP, HL, and conductance were tightly coupled with the circadian Tb rhythm at both ambient temperatures (TA). At 17°C, increased HP compensated for higher HL at all phases of the Tb rhythm, resulting in only minor changes to Tb. Parallel compensatory changes of HP and HL were seen at all rhythm phases at both TA. Similar time courses of Tb, HP, and HL in their respective rhythms and the relative stability of Tb during both active and rest periods suggest action of the circadian timing system on Tb set point.

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Roh, Hyun Woong, et Sang Joon Son. « Rest-Activity Pattern and Circadian Phase Alterations Across the Alzheimer’s Disease Clinical Spectrum ». Chronobiology in Medicine 3, n^o 4 (31 décembre 2021) : 137–41. http://dx.doi.org/10.33069/cim.2021.0029.

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Actigraphy-derived locomotor activity recordings are novel and critical tools for evaluating rest-activity pattern and circadian phase in humans. We conducted a narrative review assessing rest-activity pattern and circadian phase alterations within various stages of Alzheimer’s disease, in consideration of the reciprocal associations between neurodegeneration and circadian rhythm disruption in patients with Alzheimer’s disease. The goal of this review was to characterize possible associations between circadian rhythm disruption and neurodegeneration in Alzheimer’s disease. To the best of our knowledge, only two studies have assessed rest-activity pattern and circadian phase alterations in the preclinical Alzheimer’s disease stage and the results of the studies were inconsistent. Several studies have evaluated rest-activity pattern and circadian phase alterations in patients with Alzheimer’s dementia. The most replicated findings were delayed phase and increased activity fragmentation, represented as increased intra-daily variability. Unfortunately, many studies performed in dementia patients have not examined neuroimaging biomarkers or structured neuropsychological tests, thus limiting the specification of dementia clinical diagnoses. Future studies should consider a more comprehensive evaluation of various clinical and biomarker characteristics in patients with dementia or Alzheimer’s disease.

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Li, Xiao, Ka Sin Caroline Shea, Lok Fan Lau, Ching Kwong Dino Wong, Waiyan Vivian Chiu, Wai Man Mandy Yu, Albert Martin Li, Y. K. Wing, Yee Ching Kelly Lai et Shirley Xin Li. « 625 The association between circadian rhythms and psychosocial functioning in children with attention deficit hyperactivity disorder ». Sleep 44, Supplement_2 (1 mai 2021) : A245. http://dx.doi.org/10.1093/sleep/zsab072.623.

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Abstract Introduction Circadian rhythm disturbances, including delayed circadian rhythm and increased motor activity, are commonly seen in attention-deficit hyperactivity disorder (ADHD). Previous research suggested a link between circadian rhythm disturbances and poor psychosocial functioning in children, but such a relationship has not been examined in children with ADHD. This study aimed at examining the association between circadian-related parameters and psychosocial functioning in children with ADHD. Methods Seventy-nine children with ADHD were recruited into this study (age range: 6–12 years, 75.9% male). They were assessed by parent-report questionnaires on sleep problems (Children’s Sleep Habits Questionnaire, CSHQ), ADHD symptoms (Strengths and Weaknesses of ADHD Symptoms and Normal Behaviour Scale, SWAN), and psychosocial functioning (Strengths and Difficulties Questionnaire, SDQ). Actigraphic data collected for seven consecutive days were analyzed using parametric and nonparametric methods. The relationship between circadian parameters and psychosocial functioning was analyzed using multiple regression while controlling for age, sex, ADHD medication, total sleep time, and CSHQ total score. Results Later acrophase was significantly associated with higher scores on SDQ emotional problems (St. β = 0.30, p = 0.03) and SWAN inattention subscale (St. β = 0.27, p = 0.043). Lower relative amplitude was associated with higher scores on SDQ hyperactivity symptoms (St. β = -0.29, p = 0.045) and SDQ total difficulties (St. β = -0.31, p = 0.036). Higher levels of mean activity level during the least active 5-h period (L5) were related to higher scores on SDQ peer problems (St. β = 0.38, p = 0.021), SDQ internalizing problems (St. β = 0.38, p = 0.020) and SDQ total difficulties (St. β = 0.33, p = 0.036). Later onset of L5 was associated with increased SDQ emotional problems (St. β = 0.26, p = 0.046). Conclusion Circadian rest-activity rhythm disturbances (delayed phase, blunted rest-activity rhythms, higher level of nocturnal activity, and later onset of nocturnal rest) were associated with poor psychosocial functioning in children with ADHD. Further longitudinal studies are needed to examine the effects of circadian disruption on psychosocial functioning in children with ADHD. Support (if any) This work was supported by the Health and Medical Research Fund (Project No.: 30160604).

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Gao, Qian, Juan Sheng, Song Qin et Luoying Zhang. « Chronotypes and affective disorders : A clock for mood ? » Brain Science Advances 5, n^o 3 (septembre 2019) : 145–60. http://dx.doi.org/10.26599/bsa.2019.9050018.

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Affective disorders are often accompanied by circadian rhythm disruption and the major symptoms of mental illness occur in a rhythmic manner. Chronotype, also known as circadian preference for rest or activity, is believed to exert a substantial influence on mental health. Here, we review the connection between chronotypes and affective disorders, and discuss the potential underlying mechanisms between these two phenomena.

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Xu, Yanyan, Shaoyong Su, William V. McCall, Carlos Isales, Harold Snieder et Xiaoling Wang. « Rest-activity circadian rhythm and impaired glucose tolerance in adults : an analysis of NHANES 2011–2014 ». BMJ Open Diabetes Research & ; Care 10, n^o 2 (mars 2022) : e002632. http://dx.doi.org/10.1136/bmjdrc-2021-002632.

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IntroductionCircadian rhythm disturbance occurs in type 2 diabetes, yet it is unknown whether it also exists in the prediagnostic phase of the disease. Thus, we examined the association of rest-activity circadian rhythm with 2-hour glucose levels and the risk of impaired glucose tolerance (IGT) in a nationally representative sample of adults without diabetes using a cross-sectional design.Research design and methodsWe analyzed data from 2760 adults without diabetes (age ≥20) with at least 4 days of validated accelerometer recordings and a valid oral glucose tolerance test from the National Health and Nutrition Examination Survey 2011–2014. Non-parametric rest-activity circadian rhythm parameters were derived from the accelerometer recordings.ResultsIn the models adjusting for multiple covariates, a one-quantile increase in relative amplitude (ie, increased circadian rhythmicity) was associated with 2.66 mg/dL decrease in 2-hour glucose level (95% CI −3.94 to −1.38, p<0.001) and a decreased odds of IGT (OR 0.75, 95% CI 0.63 to 0.89, p=0.002). A one-quantile increase in intradaily variability (ie, increased rhythm fragmentation) was associated with 3.01 mg/dL increase in 2-hour glucose level (95% CI 1.52 to 4.49, p=0.001) and an increased odds of IGT (OR 1.37, 95% CI 1.19 to 1.58, p<0.001).ConclusionsCircadian disruption is significantly associated with impaired glucose homeostasis in a general population of adults without diabetes. The association of circadian rhythm abnormalities with indicators of the pre-diabetic state suggests that circadian dysfunction may contribute to early disease pathogenesis.

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Li, Xiao-Mei, Xu-Hui Liu, Elisabeth Filipski, Gérard Metzger, Philippe Delagrange, Jean-Philippe Jeanniot et Francis Lévi. « Relationship of atypical melatonin rhythm with two circadian clock outputs in B6D2F1 mice ». American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 278, n^o 4 (1 avril 2000) : R924—R930. http://dx.doi.org/10.1152/ajpregu.2000.278.4.r924.

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Circadian rhythms in body temperature, locomotor activity, and the circadian changes of plasma and pineal melatonin content were investigated in B6D2F1mice synchronized by 12 h of light and 12 h of darkness. During 8 wk continuous recording, activity and temperature displayed a marked stable and reproducible circadian rhythm, with both peaks occurring near the middle of darkness. Both 24- and 12-h rhythmic components were also significantly detected. Mean plasma melatonin concentration rose steadily during the light span and reached a maximum (30.6 ± 10.0 pg/ml) at 11 h after light onset (HALO), then gradually decreased after the onset of darkness to a nadir (4.7 ± 0.4 pg/ml) at 20 HALO. Mean pineal content followed a pattern parallel to that of plasma concentration (peak at 11 HALO: 17.7 ± 1.0 pg/gland; trough at 17 HALO: 4.7 ± 1.0 pg/gland). In addition, a second sharp peak was observed at 21 HALO (20.2 ± 3.5 pg/gland). Plasma and pineal contents displayed large and statistically significant circadian changes, with a composite rhythm of period (24 + 12 h). This mouse model has predominant production and secretion of melatonin during the day. This possibly contributes to a similar coupling between chronopharmacology mechanisms and the rest-activity cycle in these mice and in human subjects.

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Hammad, Grégory, Mathilde Reyt, Nikita Beliy, Marion Baillet, Michele Deantoni, Alexia Lesoinne, Vincenzo Muto et Christina Schmidt. « pyActigraphy : Open-source python package for actigraphy data visualization and analysis ». PLOS Computational Biology 17, n^o 10 (19 octobre 2021) : e1009514. http://dx.doi.org/10.1371/journal.pcbi.1009514.

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Over the past 40 years, actigraphy has been used to study rest-activity patterns in circadian rhythm and sleep research. Furthermore, considering its simplicity of use, there is a growing interest in the analysis of large population-based samples, using actigraphy. Here, we introduce pyActigraphy, a comprehensive toolbox for data visualization and analysis including multiple sleep detection algorithms and rest-activity rhythm variables. This open-source python package implements methods to read multiple data formats, quantify various properties of rest-activity rhythms, visualize sleep agendas, automatically detect rest periods and perform more advanced signal processing analyses. The development of this package aims to pave the way towards the establishment of a comprehensive open-source software suite, supported by a community of both developers and researchers, that would provide all the necessary tools for in-depth and large scale actigraphy data analyses.

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Yang, Hui-Wen, Sarah Chellappa, Arlen Gaba, Christian Cajochen et Kun Hu. « 758 Circadian rest-activity signatures in women with major depressive disorder ». Sleep 44, Supplement_2 (1 mai 2021) : A295—A296. http://dx.doi.org/10.1093/sleep/zsab072.755.

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Abstract Introduction Patients with major depressive disorder (MDD) show disrupted circadian rhythms and sleep, including reduced daytime physical activity and poor sleep quality. However, previous findings are masked by psychotropic medication intake, co-morbid diseases and years of chronic mental illness. Here, we aim at identifying circadian motor activity patterns in unmedicated women at the onset of MDD. Methods Twelve young unmedicated women with MDD (Mean+-SD: 24.9+-5.2y; range: 18-33y) and eight age-matched healthy women (Mean+-SD: 24.5+-3.2y; range: 20-31y) participated in our study. Activity recordings were collected using wrist-worn wearable devices (actigraphs) for ~7 days in real-life settings. Cosinor analyses were performed to assess the amplitude and phase of the 24-h rest-activity activity rhythms. Non-parametric analyses were used to quantify interdaily stability and intradaily variability of the rest-activity rhythm. Furthermore, we calculated the mean activity level and scaling exponent alpha, which quantifies the temporal correlation in activity fluctuations, per 3-h bins across the 24-h sleep-wake cycle. Results Women with MDD showed a significantly higher amplitude of the 24-h rest-activity activity rhythm (Mean+-SD: 332.7+-120.8 arbitrary units) than the controls (179.7+-122.9; p=0.002), elicited by higher activity levels during the daytime (0-12h after habitual wake-up time; p<0.01). In contrast, women with MDD showed a trend for lower interdaily stability levels than controls (respectively, 0.41+-0.07 and 0.46+-0.08; p=0.05). Interestingly, a significant interaction effect of “group” and “time since habitual wake” was elicited for scaling exponent alpha (p<0.001). Accordingly, women with MDD had higher alpha values during habitual sleep (0–6 hours before habitual wake-up time) than controls (respectively, 1.18+-0.22 and 1.12+-0.22). Conclusion Unmedicated women at the onset of MDD had altered circadian motor activity patterns, as indexed by higher amplitude particularly during daytime while awake, less stable 24-h activity rhythms, and highly correlated activity patterns during sleep that closely resemble those typically occurring during wakefulness. These findings suggest that MDD per se may be associated with impaired rest-activity profiles. Ultimately, the use of wearable devices might hold important prospects for the early detection of individuals at risk for mood disorders. Support (if any) Swiss National Science Foundation Grants START #3100–055385.98, 3130-0544991.98 and 320000-108108; NIH RF1AG064312, RF1AG059867

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Stahl, Sarah. « DIGITAL MONITORING OF SLEEP, MEALS, AND EXERCISE AS A PREVENTIVE INTERVENTION FOR DEPRESSION IN BEREAVED SPOUSES ». Innovation in Aging 3, Supplement_1 (novembre 2019) : S604. http://dx.doi.org/10.1093/geroni/igz038.2249.

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Abstract The death of a spouse brings profound change to bereaved survivors’ lifestyle and daily routine. These changes disrupt circadian rhythms which, in turn, places individuals at high risk for depression. The purpose of this study is to examine the feasibility and acceptability of a 12-week behavioral intervention that targets the timing and regularity of sleep, meals, and physical activity via digital monitoring and motivational health coaching. Participants were 60+ years of age and assessed on intervention acceptability and adherence, depression symptoms (Hamilton Rating Scale for Depression) and the rest-activity rhythm, (a downstream indicator of the body’s circadian rhythm (via actigraphic technology). The intervention was rated highly by participants (n=55); 88% were compliant in digital monitoring and 95% were retained. Depression symptoms declined from pre-to post-intervention; and the regularity of circadian rhythms increased. An intervention that targets the regularity of day- and nighttime activities may reduce depression in older spousally-bereaved adults.

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Sultan, Armiya, Vivek Choudhary et Arti Parganiha. « Characteristics of circadian rhythms in rest-activity and energy expendi-ture in cancer in-patients ». South Asian Journal of Experimental Biology 4, n^o 6 (4 février 2015) : 327–35. http://dx.doi.org/10.38150/sajeb.4(6).p327-335.

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The objective of the current study was to assess the rest-activity (RA) and energy expenditure (EE) rhythms in cancer in-patients. Twenty chemothera-py receiving cancer in-patients (10 males and 10 females) and ten apparently healthy human subjects (5 males and 5 females) wore a non-invasive elec-tronic device – the Actical on their non dominant wrist. Data were recorded at 1-minute epoch for at least 3-4 consecutive days. Significant differences in RA and EE patterns were observed between cancer in-patients and control subjects, irrespective of gender. Control subjects showed absolute rhythm detection ratio in RA and EE, whereas, ratio was of low magnitude in cancer patients, especially with reference to EE. Statistically significant decrement in circadian amplitudes and advancement in circadian peaks of RA and EE were observed in cancer in-patients as compared to control subjects. Significant independent effects of factors, namely ‘disease’ and ‘gender’ on total activity count (TAC), average activity count (AAC), total energy expenditure (TEE) and average energy expenditure (AEE) were observed. TEE and AEE were signifi-cantly lower in cancer in-patients as compared to control subjects. Further, factors, ‘disease’ and ‘gender’ also produced significant effects on activity energy expenditure (AcEE), metabolic energy expenditure (MET) and resting energy expenditure (REE). In conclusion, the findings indicate disruption of the circadian rhythms in rest-activity and energy expenditure in cancer in-patients. This disruption is gauged from alterations in rhythm characteristics of RA and EE. However, additional studies involving more patients are re-quired for further validation of the present findings.

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Davis, Fred C., et N. Viswanathan. « Stability of circadian timing with age in Syrian hamsters ». American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 275, n^o 4 (1 octobre 1998) : R960—R968. http://dx.doi.org/10.1152/ajpregu.1998.275.4.r960.

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The causes of age-related disruptions in the timing of human sleep and wakefulness are not known but may include changes in both the homeostatic and circadian regulation of sleep. In Syrian hamsters the free running period of the circadian activity/rest rhythm has been reported to shorten with age. Although this has been observed under a variety of experimental conditions, the changes have been small and their consistency uncertain. In the present study, the wheel running activity/rest rhythm was continuously measured in male Syrian hamsters ( Mesocricetus auratus) in dim constant light (<1 lx) from 8 wk of age until death. Fifteen hamsters survived to at least 90 wk (28%). The average free running period of these hamsters did not change with age. In 18 hamsters that died between 50 and 88 wk, free running period also did not change before death. In contrast to free running period, other measures related to activity level changed significantly with age and before death. Despite changes in the expression of the activity/rest rhythm, the free running period of the hamster circadian pacemaker remained remarkably stable with age.

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Mesquita, Maria Eugênia, Maria Eliza Finazzi, Bruno Gonçalves, Lee Fu-I, Leandro L. Duarte, José Ricardo Lopes, José Alberto Del-Porto et Luiz Menna-Barreto. « Activity/rest rhythm of depressed adolescents undergoing therapy : case studies ». Trends in Psychiatry and Psychotherapy 38, n^o 4 (décembre 2016) : 216–20. http://dx.doi.org/10.1590/2237-6089-2015-0053.

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Abstract Introduction: Disorders of circadian rhythms have been reported in studies of both depressed children and of depressed adolescents. The aim of this study was to evaluate whether there is a relationship between the 24-hour spectral power (24h SP) of the activity/rest rhythm and the clinical course of depression in adolescents. Methods: Six 14 to 17-year-old adolescents were recruited for the study. They were all suffering from major depressive disorder, according to the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) criteria, as identified by the Schedule for Affective Disorders and Schizophrenia for School Aged Children: Present and Lifetime Version (K-SADS-PL). Depressive symptoms were assessed using the Children's Depression Rating Scale - Revised (CDRS-R) and clinical evaluations. Locomotor activity was monitored over a period of 13 consecutive weeks. Activity was measured for 10-minute periods using wrist-worn activity monitors. All patients were prescribed sertraline from after the first week up until the end of the study. Results: We found a relationship between high CDRS values and low 24-hour spectral power. Conclusions: The 24h SP of the activity/rest rhythm correlated significantly (negatively) with the clinical ratings of depression.

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Li, Xiao, Ka Sin Caroline Shea, Ching Kwong Dino Wong, Waiyan Vivian Chiu, Lok Fan Lau, Wai Man Mandy Yu, Albert Martin Li, Y. K. Wing, Yee Ching Kelly Lai et Shirley Xin Li. « 624 The association of circadian rhythms with cognitive functioning in children with attention-deficit hyperactivity disorder ». Sleep 44, Supplement_2 (1 mai 2021) : A245. http://dx.doi.org/10.1093/sleep/zsab072.622.

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Abstract Introduction Disrupted circadian rhythms is associated with impaired cognitive function. Although circadian rhythm disturbances are commonly seen in individuals with attention-deficit hyperactivity disorder (ADHD), whether their cognitive functioning is thus affected remains unclear. This study aimed to examine the associations of circadian-related parameters with different cognitive abilities in children with ADHD. Methods Fifty-seven children with ADHD were recruited into this study (age range: 6–12 years, 66.7% male). They were assessed by parent-report questionnaires on sleep problems (Children’s Sleep Habits Questionnaire, CSHQ), and ADHD symptoms (Strengths and Weaknesses of ADHD Symptoms and Normal Behaviour Scale). Actigraphic data collected for seven consecutive days were analyzed using parametric and nonparametric methods. Cognitive functioning was assessed with Continuous Performance Test (CPT) for sustained attention, Letter-digit test for processing speed, Digit Span test and N-back task for working memory, Tower of London test for planning skills and Bergs Card Sorting Test for set-shifting ability. The relationship between circadian parameters and cognitive performance was analyzed using multiple regression while controlling for age, sex, ADHD medication, the day of cognitive assessment (school days vs non-school days), total sleep time, and CSHQ total score. Results Increased activity during the most active 10-h period of the day (St. β = 0.39, p = 0.012) was related to more omission errors on CPT, and later onset of the least active 5-h period of the day (St. β = 0.44, p = 0.004) was associated with longer correct reaction time on CPT. Lower relative amplitude was associated with poorer performance on Digit Span (St. β = 0.33, p = 0.042). No significant associations were found between the circadian-related parameters and the performance on other tasks measuring processing speed and executive functions. Conclusion Circadian rest-activity rhythms (blunted rest-activity rhythms, higher daytime activity, and later onset of nocturnal rest) were associated with cognitive functioning in ADHD children. Future longitudinal studies are needed to explore the long-term impact of circadian rhythm disturbances and the effects of circadian-focused intervention on cognitive functioning in ADHD children. Support (if any) This work was supported by the Health and Medical Research Fund (Project No.: 30160604).

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Innominato, Pasquale F., Oxana Palesh, Georg A. Bjarnason, Ayhan Ulusakarya, David Spiegel et Francis Levi. « Symptoms associated with circadian rest-activity rhythm disruption in 237 patients with metastatic colorectal cancer. » Journal of Clinical Oncology 33, n^o 29_suppl (10 octobre 2015) : 1. http://dx.doi.org/10.1200/jco.2015.33.29_suppl.1.

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1 Background: The circadian timing system exerts temporal control over physiology, generating rhythms of about 24 hours. Its alteration in benign conditions has been associated with several systemic symptoms, including fatigue, appetite loss and poor sleep. However, the clinical impact of circadian disruption in cancer patients remains overlooked. We hypothesized that patients with circadian disruption would report more severe symptoms than those with robust circadian function. Methods: Data were available for 237 patients with metastatic colorectal cancer: M/F ratio: 1.66; median age: 60.4 years; range: 20.7-77.6; WHO Performance Status (PS) = 0/1: 59.7%/33.5%. We estimated the occurrence of circadian disruption using a validated parameter (the dichotomy index I < O), derived from wrist-actigraphy for at least 72 consecutive hours. Symptoms were self-reported by the patients using the EORTC QLQ-C30 questionnaire. Mann-Whitney U test was used to compare symptom severity according to the presence or absence of circadian disruption. Cohen’s d effect sizes were computed to evaluate the clinical meaningfulness of the observed differences. Subgroup analyses were performed according to gender, age, and WHO Performance Status (PS). Results: Circadian disruption (I < O lower than or equal to 97.5%) occurred in 130 (54.9%) patients. Fatigue (p < 0.0001), appetite loss (p < 0.0001), difficulty sleeping (p = 0.009), pain (p < 0.0001) and dyspnea (p = 0.001) were significantly more severe in patients with circadian disruption than in those with robust circadian function. Largest effect sizes were observed for fatigue (0.64), appetite loss (0.59) and pain (0.57). Subgroup analyses showed similar results, regardless of gender, age or PS. Conclusions: In this large international study, the presence of circadian disruption was associated with a clinically meaningfully higher severity of fatigue, appetite loss, pain, dyspnea and sleep problems. Correcting circadian dysfunction with the use of pharmacological and/or behavioural interventions could improve these often difficult-to-manage systemic symptoms.

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Dowling, Glenna A., Erin M. Hubbard, Judy Mastick, Jay S. Luxenberg, Robert L. Burr et Eus J. W. Van Someren. « Effect of morning bright light treatment for rest–activity disruption in institutionalized patients with severe Alzheimer's disease ». International Psychogeriatrics 17, n^o 2 (13 mai 2005) : 221–36. http://dx.doi.org/10.1017/s1041610205001584.

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Background: Disturbances in rest–activity rhythm are prominent and disabling symptoms in Alzheimer's disease (AD). Nighttime sleep is severely fragmented and daytime activity is disrupted by multiple napping episodes. In most institutional environments, light levels are very low and may not be sufficient to enable the circadian clock to entrain to the 24-hour day. The purpose of this randomized, placebo-controlled, clinical trial was to test the effectiveness of morning bright light therapy in reducing rest–activity (circadian) disruption in institutionalized patients with severe AD.Method: Subjects (n=46, mean age 84 years) meeting the NINCDS-ADRDA (National Institute of Neurological and Communicative Disorders and Stroke – the Alzheimer's Disease and Related Disorders Association) AD diagnostic criteria were recruited from two large, skilled nursing facilities in San Francisco, California. The experimental group received one hour (09:30–10:30) of bright light exposure (≥2500lux in gaze direction) Monday through Friday for 10weeks. The control group received usual indoor light (150–200lux). Nighttime sleep efficiency, sleep time, wake time and number of awakenings and daytime wake time were assessed using actigraphy. Circadian rhythm parameters were also determined from the actigraphic data using cosinor analysis and nonparametric techniques. Repeated measures analysis of variance (ANOVA) was used to test the primary study hypotheses.Results and conclusion: Although significant improvements were found in subjects with aberrant timing of their rest–activity rhythm, morning bright light exposure did not induce an overall improvement in measures of sleep or the rest–activity in all treated as compared to control subjects. The results indicate that only subjects with the most impaired rest–activity rhythm respond significantly and positively to a brief (one hour) light intervention.

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Stefani, A. « 0813 Circadian Rest-activity Rhythm In Isolated Rem Sleep Behavior Disorder ». Sleep 43, Supplement_1 (avril 2020) : A309. http://dx.doi.org/10.1093/sleep/zsaa056.809.

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Abstract Introduction Isolated REM sleep behavior disorder (iRBD) is a parasomnia characterized by abnormal behaviours occurring during REM sleep. Several studies showed that iRBD is a prodromal stage of synucleinopathies. Therefore identifying iRBD in the general population is of utmost importance. Aim of this study was to explore whether the assessment of circadian rest-activity rhythm features, measured by actigraphy, can distinguish iRBD patients from patients suffering from disorders characterized by other pathological motor activity during sleep and healthy controls. Methods Nineteen subjects with video-polysomnographic (v-PSG) diagnosis of iRBD, 39 subjects with other disorders with motor activity during sleep (19 restless leg syndrome -RLS- and 20 untreated sleep apnea syndrome patients -SAS) and 16 healthy controls underwent 2-week actigraphy, v-PSG, and completed RBD screening questionnaires. Nonparametric analyses were applied to assess rest-activity rhythm features; daytime napping was also evaluated. The diagnostic value of nonparametric measures has been assessed through ROC curve. Results iRBD patient showed lower sleep efficiency, increased WASO and increased frequency of prolonged activity bouts compared to RLS and controls, while no difference emerged with SAS patients. Moreover, iRBD patients presented increased occurrence of estimated nap in comparison to RLS, SAS and controls. The nonparametric measure I<O distinguished iRBD patients from RLS, SAS and controls with an area under the curve greater than that of RBD screening questionnaires. Conclusion The nonparametric index I<O is able to distinguish iRBD patients from patients with other pathological motor activity during sleep and controls, confirming its potential use as an objective measure suitable to screen large at-risk populations. Support This study was supported by a grant from the Austrian Science Fund (FWF) to Birgit Högl, I 2120-B27.

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Leng, Y., T. Blackwell, P. M. Cawthon, S. Ancoli-Israel, K. Stone et K. Yaffe. « 1145 Longitudinal Association Between Circadian Activity Rhythms And Risk Of Incident Parkinson’s Disease In Older Men ». Sleep 43, Supplement_1 (avril 2020) : A436. http://dx.doi.org/10.1093/sleep/zsaa056.1139.

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Abstract Introduction Disruption in circadian activity rhythms are very common in older adults, particularly among those with neurodegenerative diseases. However, the longitudinal association between circadian disruption and subsequent risk of developing neurodegenerative diseases, including Parkinson’s disease (PD), is unclear. Methods We examined rest-activity rhythms in 2930 community-dwelling older men (mean age 76.3 ± 5.5 years) without PD and followed them for incident PD over the next 11 years. 24-h rest-activity rhythm parameters (amplitude, mesor, robustness, acrophase) were generated by wrist actigraphy-extended cosinor analysis. Incident PD cases were identified based on physician-diagnosed PD between 2005 and 2016. Logistic regression was used to determine the association between quartiles of rest-activity parameters and risk of incident PD. Results 78 (2.7%) men developed PD during 11 years of follow-up. The risk of PD increased with decreasing circadian amplitude (strength of the rhythm), mesor (mean level of activity) or robustness (how closely activity follows a cosine 24h pattern); p for trend across quartiles <0.05. After accounting for demographics, clinic site, education, depressive symptoms, body mass index, physical activity, benzodiazepine use, alcohol, caffeine, smoking, comorbidities and baseline cognition, those in the lowest quartile of amplitude, mesor or robustness had approximately three times the risk of developing PD compared to those in the highest quartile of amplitude [ORs (95% CI)= 3.11 (1.54-6.29)], mesor [3.04 (1.54-6.01)] and robustness [2.65 (1.24-5.66)]. The association remained after further adjustment for nighttime sleep disturbances and sleep duration. These associations were somewhat attenuated, but the pattern remained similar after excluding PD cases developed within 2 years after baseline. Acrophase was not significantly associated with risk of PD. Conclusion Older men with reduced circadian rhythmicity had an increased risk of incident PD over 11 years. Circadian disruption in the elderly may represent an important prodrome or risk factor for PD. Randomized trials should evaluate whether strategies to improve circadian function impact risk of PD. Support This work was supported by the NIA, NIAMS, NCATS, NIH Roadmap for Medical Research and the NHLBI under the grant numbers: U01AG027810, U01AG042124, U01AG042139, U01AG042140, U01AG042143, U01AG042145, U01AG042168, U01AR066160, UL1TR000128, R01HL071194, R01HL070848, R01HL070847, R01HL070842, R01HL070841, R01HL070837, R01HL070838, and R01HL070839.

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Levi, Francis, Sandra Komarzynski, Qi Huang, Teresa Young, Yeng Ang, Claire Fuller, Julia Brettschneider et al. « Relevance of real-time teletransmission of physical activity, sleep, and circadian rhythms from gastrointestinal cancer (GIC) patients (pts) during daily routine (IDEAs, IRAS 233972). » Journal of Clinical Oncology 38, n^o 4_suppl (1 février 2020) : 801. http://dx.doi.org/10.1200/jco.2020.38.4_suppl.801.

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801 Background: The relative amount of activity and rest over the 24-hours, as measured by the dichotomy index I < O from actimetry records, is an independent predictor of overall survival and quality of life, and an early warning signal for emergency hospitalisation. The IDEAs study aimed to determine the sleep, physical and circadian pathologies in pts during their daily routine at home, which could lower I < O and be modifiable through personalised interventions. Methods: The rest-activity and surface temperature patterns were monitored in real time using a tele-transmitting chest sensor and a GPRS-platform for one week in 25 pts, with a WHO performance status of 0-1 and metastatic GIC (colorectal, 56%). Each pt completed questionnaires including Chronotype, HADS, and Pittsburgh Sleep Index, filled a precise diary of daily activities, meals and sleep times, and the MD Anderson Symptoms Inventory daily. I < O counts the In-bed activity bouts per min that are below the median activity Out-of-bed. Other pt-specific circadian parameters were estimated with spectral analyses and Hidden Markov models (HMM). I < O predictors were identified through correlation and regression analyses. Results: A poor I < O was found for 13 pts (52%). Self-reported scores for sleep quality or physical fitness showed no significant differences according to I < O. Yet HMM-modelled rest-activity revealed that pts with poor I < O had lower activity out-of-bed (median activity counts per minute, 110 vs 52, p = 0.001) and fractionated sleep (probability of remaining at rest when asleep, 94% vs 90%, p = 0.01). Poor I < O was significantly associated with an abnormal circadian rhythm in chest surface temperature, that was either wrongly timed or suppressed, for 83% of the pts as compared to 25% of those with a good I < O (p = 0.012). Conclusions: Nearly half of the pts displayed altered circadian rest-activity rhythm, with poor sleep and low daytime activity. In most of them, the circadian rhythm in body temperature, which critically regulates sleep, was abnormal. Exploration and specific treatment of sleep and circadian disorders are warranted for improving outcomes in cancer pts. Clinical trial information: 233972.

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Lévi, Francis, Sandra Komarzynski, Qi Huang, Teresa Young, Yeng Ang, Claire Fuller, Matei Bolborea et al. « Tele-Monitoring of Cancer Patients’ Rhythms during Daily Life Identifies Actionable Determinants of Circadian and Sleep Disruption ». Cancers 12, n^o 7 (17 juillet 2020) : 1938. http://dx.doi.org/10.3390/cancers12071938.

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The dichotomy index (I < O), a quantitative estimate of the circadian regulation of daytime activity and sleep, predicted overall cancer survival and emergency hospitalization, supporting its integration in a mHealth platform. Modifiable causes of I < O deterioration below 97.5%—(I < O)low—were sought in 25 gastrointestinal cancer patients and 33 age- and sex-stratified controls. Rest-activity and temperature were tele-monitored with a wireless chest sensor, while daily activities, meals, and sleep were self-reported for one week. Salivary cortisol rhythm and dim light melatonin onset (DLMO) were determined. Circadian parameters were estimated using Hidden Markov modelling, and spectral analysis. Actionable predictors of (I < O)low were identified through correlation and regression analyses. Median compliance with protocol exceeded 95%. Circadian disruption—(I < O)low—was identified in 13 (52%) patients and four (12%) controls (p = 0.002). Cancer patients with (I < O)low had lower median activity counts, worse fragmented sleep, and an abnormal or no circadian temperature rhythm compared to patients with I < O exceeding 97.5%—(I < O)high—(p < 0.012). Six (I < O)low patients had newly-diagnosed sleep conditions. Altered circadian coordination of rest-activity and chest surface temperature, physical inactivity, and irregular sleep were identified as modifiable determinants of (I < O)low. Circadian rhythm and sleep tele-monitoring results support the design of specific interventions to improve outcomes within a patient-centered systems approach to health care.

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Alfini, Alfonso, Marilyn Albert, Andreia Faria, Anja Soldan, Corinne Pettigrew, Sarah Wanigatunga, Vadim Zipunnikov et Adam Spira. « 045 Associations of Actigraphic Sleep and Circadian Rest/Activity Rhythms with Cognition in the Early Phase of Alzheimer’s Disease ». Sleep 44, Supplement_2 (1 mai 2021) : A19—A20. http://dx.doi.org/10.1093/sleep/zsab072.044.

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Abstract Introduction Alterations in sleep and circadian rhythms are common in persons with Alzheimer’s disease (AD) dementia, but the nature of such changes in the early phases of AD remains unclear. This study compared sleep and circadian rest/activity rhythms (RARs), measured by standard and novel actigraphic indices, between participants with normal cognition or mild cognitive impairment (MCI), and examined cross-sectional associations between these measures and cognition. Methods Actigraphy data were collected in 179 individuals (mean age=72.6 years, gender=64.8% female) with normal cognition (n=153) or MCI (n=26) from the Biomarkers for Older Controls at Risk of Dementia (BIOCARD) study. Standard sleep parameters (i.e., total sleep time [TST], sleep efficiency [SE], wake after sleep onset [WASO], average wake bout length [WBL]), and standard non-parametric RAR metrics (i.e., relative amplitude [RA], intradaily variability [IV], interdaily stability [IS]) were generated. Functional principal component (fPC) methods were used to generate three novel RAR indices (fPC1, fPC2, fPC3) representing 69% of the total variance. Cognitive test scores were used to generate composite measures reflecting the domains of episodic memory and executive function using factor analysis. Regression models were used to compare sleep and circadian RAR parameters between the diagnostic groups and to evaluate their associations with cognitive performance. Results After adjustment for age, sex, education, and APOE-4 genotype, compared to normal controls, MCI subjects had significantly lower SE, lower RA, and lower scores on the novel RAR measure fPC3, which reflects a later rhythm phase, lower amplitude, and lower activity both at night and early in the day. In analyses combining data from participants with MCI and controls, several standard RAR parameters (e.g., higher RA and IS) and higher fPC3 scores were associated with both better episodic memory and executive function. Additionally, several standard measures (e.g., lower WASO and IV) and lower fPC1 scores (reflecting higher rhythm amplitude and greater activity throughout daytime hours) were linked with better executive function. Conclusion MCI participants have sleep and circadian alterations, which are significantly associated with cognitive performance. A novel RAR measure, fPC3, showed differences in rhythm patterns that extended from the night into the daytime. Support (if any) Funding-support NIA (U19-AG033655, T32-AG027668, R01-AG050507) and AASMF (#223-BS-19).

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Sommer, Rosa, Lei Yu, Julie A. Schneider, David A. Bennett, Aron S. Buchman et Andrew S. P. Lim. « Disrupted Rest-Activity Rhythms and Cerebral Small Vessel Disease Pathology in Older Adults ». Stroke 52, n^o 7 (juillet 2021) : 2427–31. http://dx.doi.org/10.1161/strokeaha.120.030870.

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Background and Purpose: The pathogenesis of cerebral small vessel disease remains incompletely understood. The relationship between circadian rhythm disturbances and histopathologic measures of cerebral small vessel disease has not been studied. We hypothesized that disrupted circadian rest-activity rhythms would be associated with a higher burden of cerebral small vessel disease pathology. Methods: We studied 561 community-dwelling older adults (mean age at death, 91.2, 27.4% male) from the Rush Memory and Aging Project. We used actigraphy to quantify several measures of 24-hour rest-activity rhythmicity, including interdaily stability, intradaily variability, and amplitude, and used ordinal logistic regression models to relate these measures to the severity of cerebral arteriolosclerosis, atherosclerosis, macroinfarcts, and microinfarcts, assessed at autopsy. Results: Lower interdaily stability was associated with a higher burden of arteriolosclerosis, higher intradaily variability was associated with a higher burden of atherosclerosis and subcortical infarcts, and lower amplitude was associated with a higher burden of arteriosclerosis, atherosclerosis and subcortical macroinfarcts. Moreover, the associations between interdaily stability and arteriolosclerosis and intradaily variability and subcortical infarcts were independent of cardiovascular risk factors, sleep fragmentation, and medical comorbidities. Conclusions: Disrupted rest-activity rhythms are associated with a greater burden of cerebral small vessel disease in older adults.

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Spiegel, David, Pierre-Antoine Dugué, Pasquale F. Innominato, Abdoulaye Karaboué, Garance Dispersyn, Arti Parganiha, Sylvie Giacchetti et al. « Circadian rest-activity rhythm as a predictor of survival in metastatic colorectal cancer. » Journal of Clinical Oncology 30, n^o 15_suppl (20 mai 2012) : e14006-e14006. http://dx.doi.org/10.1200/jco.2012.30.15_suppl.e14006.

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e14006 Background: Experimental disruption of the Circadian Timing System (CTS) accelerates cancer progression. The relative amount of activity in-bed versus out-of-bed (I<O) was identified as a quantitative CTS estimate that predicted survival in two cohorts of patients with metastatic colorectal cancer (CI, CII). Methods: The independent prognostic value of I<O was investigated for Overall Survival (OS) and Progression-Free Survival (PFS) 1) in a new cohort of 142 patients (CIII) receiving circadian-based salvage treatment for metastatic colorectal cancer, and 2) in a pooled population of 436 patients from cohorts I-III. All patients had two-day rest-activity rhythm monitoring and then received a new treatment. Cohort-adjusted data were analyzed with log rank and multivariate Cox analyses. Results: Patients in CIII had poor prognosis disease compared to CI and CII, as assessed by prior chemotherapy (CIII, 69%; CI, 59.5%; CII, none), prior oxaliplatin (CIII, 55%; CII, none; CI, 2%) and/or irinotecan (CIII, 39.4%; CII, none; CI, 7%). The 273 male and 163 female patients in the pooled population had generally good performance status 0 (60.7%) or 1 (33.1%) and 51% had two or more metastatic sites. Following rest-activity rhythm determination, patients received a median of 8 chemotherapy courses. Median OS was 21.6 months [95% Confidence Limits, 17.8 to 25.5] in the patients with I<O above the cutoff median value of 97.5% as compared to 11.9 months [10.4 to 13.3] in those with a lower I<O (p from Log rank < 0.001). The adjusted relative risk related to I<O above cutoff was 0.587 [0.477 to 0.722] for earlier death (p<0.001) and 0.661 [0.542 to 0.807] for earlier progression (p <0.001). Conclusions: The circadian biomarker indicator I<O is a robust and independent quantitative long-term predictor of both OS and PFS in patients with metastatic colorectal cancer. Cancer patients with low I<O could potentially benefit from specific treatments for circadian disruption in order to enhance survival.

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Yavuz-Kodat, Enise, Eve Reynaud, Marie-Maude Geoffray, Nadège Limousin, Patricia Franco, Frédérique Bonnet-Brilhault, Patrice Bourgin et Carmen M. Schroder. « Disturbances of Continuous Sleep and Circadian Rhythms Account for Behavioral Difficulties in Children with Autism Spectrum Disorder ». Journal of Clinical Medicine 9, n^o 6 (24 juin 2020) : 1978. http://dx.doi.org/10.3390/jcm9061978.

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Sleep disorders are among the most common comorbidities in children with Autism Spectrum Disorder (ASD), and subjectively defined sleep disturbances have been related to ASD symptom severity. However, no study has investigated the differential impact of objectively measured sleep and circadian rhythm disturbances on behavioral difficulties in this population. Fifty-two children with ASD aged 3–10 years underwent assessments of sleep and circadian rest–activity rhythms objectively with actigraphy and subjectively with the Children’s Sleep Habits Questionnaire. Behavioral difficulties were assessed using the ABC-C. Group comparison analyses were used to compare sleep and circadian rhythm parameters of children with higher and lower behavioral difficulties and dominance analysis to rank predictors and address multicollinearity. Children with high irritability had a shorter continuous sleep period compared to those with lower irritability (−60 min, p = 0.04), as well as those with high stereotypic behaviors compared to children with less stereotypies (−75 min, p = 0.006). Objective circadian and sleep disturbances accounted together for, respectively, 17%, 18% and 36% of the variance in social withdrawal, irritability and stereotypic behaviors. The identification of both sleep and circadian rhythm disturbances as explanatory factors for behavioral difficulties warrants their inclusion in the existing behavioral management strategies for children with ASD.

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Montaruli, Angela, Lucia Castelli, Antonino Mulè, Raffaele Scurati, Fabio Esposito, Letizia Galasso et Eliana Roveda. « Biological Rhythm and Chronotype : New Perspectives in Health ». Biomolecules 11, n^o 4 (24 mars 2021) : 487. http://dx.doi.org/10.3390/biom11040487.

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The circadian rhythm plays a fundamental role in regulating biological functions, including sleep–wake preference, body temperature, hormonal secretion, food intake, and cognitive and physical performance. Alterations in circadian rhythm can lead to chronic disease and impaired sleep. The circadian rhythmicity in human beings is represented by a complex phenotype. Indeed, over a 24-h period, a person’s preferred time to be more active or to sleep can be expressed in the concept of morningness–eveningness. Three chronotypes are distinguished: Morning, Neither, and Evening-types. Interindividual differences in chronotypes need to be considered to reduce the negative effects of circadian disruptions on health. In the present review, we examine the bi-directional influences of the rest–activity circadian rhythm and sleep–wake cycle in chronic pathologies and disorders. We analyze the concept and the main characteristics of the three chronotypes.

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Vitale, Jacopo Antonino, Giuseppe Banfi, Marco Sias et Antonio La Torre. « Athletes’ rest-activity circadian rhythm differs in accordance with the sport discipline ». Chronobiology International 36, n^o 4 (14 février 2019) : 578–86. http://dx.doi.org/10.1080/07420528.2019.1569673.

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Van Someren, Eus J. W., Annemarieke Kessler, Majid Mirmiran et Dick F. Swaab. « Indirect bright light improves circadian rest-activity rhythm disturbances in demented patients ». Biological Psychiatry 41, n^o 9 (mai 1997) : 955–63. http://dx.doi.org/10.1016/s0006-3223(97)89928-3.

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Witting, W., I. H. Kwa, P. Eikelenboom, M. Mirmiran et D. F. Swaab. « Alterations in the circadian rest-activity rhythm in aging and Alzheimer's disease ». Biological Psychiatry 27, n^o 6 (mars 1990) : 563–72. http://dx.doi.org/10.1016/0006-3223(90)90523-5.

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Whitehead, Daisy L., Ann D. M. Davies, Jeremy R. Playfer et Christopher J. Turnbull. « Circadian rest-activity rhythm is altered in Parkinson's disease patients with hallucinations ». Movement Disorders 23, n^o 8 (15 juin 2008) : 1137–45. http://dx.doi.org/10.1002/mds.22057.

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Tsai, Shao-Yu, Kathryn E. Barnard, Martha J. Lentz et Karen A. Thomas. « Mother-Infant Activity Synchrony as a Correlate of the Emergence of Circadian Rhythm ». Biological Research For Nursing 13, n^o 1 (26 août 2010) : 80–88. http://dx.doi.org/10.1177/1099800410378889.

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Objective: Entrainment to the day—night cycle is critical for infant sleep and social development. Synchronization of infant circadian systems with the social 24-hr day may require maternal activity signals as an entraining cue. This descriptive and exploratory research examines the activity level and circadian pattern in mothers and infants. Method: Twenty-two healthy mothers and their infants (postnatal age 49.8 ± 17.1 days) wore actigraph monitors for seven days. Daytime (06:00—21:59) and nighttime (22:00—05:59) activity levels and circadian parameters of rest—activity patterns (i.e., mesor, amplitude, acrophase, and 24-hr cosinor fit) were calculated. Results: Mothers and infants were significantly more active during the day than at night. The goodness-of-fit index for the model (R2) indicates that circadian rhythm accounted for a mean of 29 ± 10% and 12 ± 8% of the variability in maternal and infant activity, respectively. Acrophase of activity occurred at 15:46 ± 1:07 for the mothers and 15:20 ± 1:21 for the infants. The mean within-dyad correlation of activity counts was r = .46 ± .11, and the within-dyad correlation was associated with the amplitude (r = .66, p < .01) and 24-hr cosinor fit of infant activity (r = .67, p < .01). Conclusions: Our findings suggest maternal rhythms as a possible exogenous influence on shaping an infant’s emerging rhythms and synchronizing them with the external light—dark cycle. Strong pattern synchrony between maternal and infant activity may support infant circadian entrainment and enhance a regular 24-hr sleep—wake schedule during the early postnatal weeks.

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Dispersyn, Garance, Laure Pain et Yvan Touitou. « Propofol Anesthesia Significantly Alters Plasma Blood Levels of Melatonin in Rats ». Anesthesiology 112, n^o 2 (1 février 2010) : 333–37. http://dx.doi.org/10.1097/aln.0b013e3181c920e2.

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Background General anesthesia combined with surgery has been shown to decrease the nocturnal peak of melatonin in patients. However, the role of anesthesia itself on melatonin secretion remains unknown. We previously showed that anesthesia induced by propofol modifies the circadian time structure in both rats and humans and phase advances the circadian rest-activity rhythm in rats. In this study, we examined the secretion of melatonin during 24 h after a 30-min propofol anesthesia in rats. Methods Rats were exposed to 12-h light/12-h dark alteration conditions and anesthetized with propofol (120 mg/kg intraperitoneally) around their peak of melatonin secretion (Zeitgeber time 16). Trunk blood samples were collected at seven subsequent Zeitgeber times to assess the effects of propofol on circadian melatonin secretion. Results Propofol modifies the peripheral melatonin by significantly decreasing its concentration ( approximately 22-28%) during the immediate 3 h after the wake up from anesthesia and then significantly increasing melatonin secretion 20 h after anesthesia ( approximately 38%). Cosinor analysis suggests that propofol induces a phase advance of the circadian secretion of peripheral melatonin. Conclusions The results demonstrate the disturbing effects of propofol anesthesia on the circadian rhythm of plasma melatonin in rats under normal light conditions. These results parallel the desynchronization of the circadian rhythms of locomotor activity and temperature previously observed after propofol anesthesia.

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Brown, Laurence A., Sibah Hasan, Russell G. Foster et Stuart N. Peirson. « COMPASS : Continuous Open Mouse Phenotyping of Activity and Sleep Status ». Wellcome Open Research 1 (15 novembre 2016) : 2. http://dx.doi.org/10.12688/wellcomeopenres.9892.1.

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Background: Disruption of rhythms in activity and rest occur in many diseases, and provide an important indicator of healthy physiology and behaviour. However, outside the field of sleep and circadian rhythm research, these rhythmic processes are rarely measured due to the requirement for specialised resources and expertise. Until recently, the primary approach to measuring activity in laboratory rodents has been based on voluntary running wheel activity. By contrast, measuring sleep requires the use of electroencephalography (EEG), which involves invasive surgical procedures and time-consuming data analysis. Methods: Here we describe a simple, non-invasive system to measure home cage activity in mice based upon passive infrared (PIR) motion sensors. Careful calibration of this system will allow users to simultaneously assess sleep status in mice. The use of open-source tools and simple sensors keeps the cost and the size of data-files down, in order to increase ease of use and uptake. Results: In addition to providing accurate data on circadian activity parameters, here we show that extended immobility of >40 seconds provides a reliable indicator of sleep, correlating well with EEG-defined sleep (Pearson’s r >0.95, 4 mice). Conclusions: Whilst any detailed analysis of sleep patterns in mice will require EEG, behaviourally-defined sleep provides a valuable non-invasive means of simultaneously phenotyping both circadian rhythms and sleep. Whilst previous approaches have relied upon analysis of video data, here we show that simple motion sensors provide a cheap and effective alternative, enabling real-time analysis and longitudinal studies extending over weeks or even months. The data files produced are small, enabling easy deposition and sharing. We have named this system COMPASS - Continuous Open Mouse Phenotyping of Activity and Sleep Status. This simple approach is of particular value in phenotyping screens as well as providing an ideal tool to assess activity and rest cycles for non-specialists.

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