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Tzischinsky O, Barel E. The Role of Sleep for Age-Related Differences in Neurobehavioral Performance. Life (Basel) 2024; 14:496. [PMID: 38672766 PMCID: PMC11051144 DOI: 10.3390/life14040496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 04/02/2024] [Accepted: 04/09/2024] [Indexed: 04/28/2024] Open
Abstract
This study investigated developmental changes from childhood to adulthood in neurobehavioral performance and sleep measures. While many studies have examined age-related changes between childhood and adolescence and from mid-to-late adulthood, young adulthood has been overlooked. The main aim of this study was to investigate the effects of sleep loss on developmental changes in neurobehavioral performance and sleepiness in a natural setting. A total of 119 children, adolescents, and young adults (38 children aged 6-9; 38 adolescents aged 13-19; and 43 young adults aged 20-27) wore an actigraph for a continuous five-weekday night. Subjective sleepiness (Karolinska Sleepiness Scale) and neurobehavioral performance (using the psychomotor vigilance test and the digit symbol substitution test) were measured on five school days. The results showed that adolescents and young adults outperformed children on both the digit symbol substitution test and the psychomotor vigilance test measures. However, adolescents committed more errors of commission on the psychomotor vigilance test and reported higher levels of subjective sleepiness. The results are discussed in relation to brain maturation in various cognitive functions.
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Affiliation(s)
- Orna Tzischinsky
- Department of Behavioral Sciences and the Center for Psychobiological Research, The Max Stern Academic College of Emek Yezreel, Emek Yezreel 1930600, Israel
| | - Efrat Barel
- School of Psychological Sciences, University of Haifa, Haifa 3103301, Israel;
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2
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Griggs S, Hernandez E, Bolton PJ, Strohl KP, Grey M, Kashyap SR, Li CSR, Hickman RL. Cognitive Behavioral Sleep Self-Management Intervention for Young Adults With Type 1 Diabetes (NCT04975230). Clin Nurs Res 2023; 32:560-570. [PMID: 36788436 PMCID: PMC10249334 DOI: 10.1177/10547738231154133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
The purpose of this study was to explore perceptions of the first dose of a cognitive behavioral sleep self-management intervention (CB-sleep) among young adults aged 18 to 25 years with type 1 diabetes (T1D). We used a qualitative descriptive approach to conduct in-depth semi-structured focused interviews with a purposive sample of 16 young adults with T1D, transitioning from adolescence to early adulthood. Interviews were audio-recorded, transcribed verbatim, and analyzed using qualitative content analysis. Participants described their sleep knowledge (previous, new, and additional), sleep health goals, along with barriers and facilitators of the CB-sleep intervention. Based on these results, we suggest CB-sleep is a useful modality with the potential to support sleep self-management in young adults with T1D during this complex life transition. Furthermore, CB-sleep could be incorporated into an existing diabetes self-management education and support program after pilot testing and determining efficacy to improve sleep and glycemic health.
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3
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Wang W, Yuan RK, Mitchell JF, Zitting KM, St Hilaire MA, Wyatt JK, Scheer FAJL, Wright KP, Brown EN, Ronda JM, Klerman EB, Duffy JF, Dijk DJ, Czeisler CA. Desynchronizing the sleep---wake cycle from circadian timing to assess their separate contributions to physiology and behaviour and to estimate intrinsic circadian period. Nat Protoc 2023; 18:579-603. [PMID: 36376588 DOI: 10.1038/s41596-022-00746-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 06/24/2022] [Indexed: 11/16/2022]
Abstract
Circadian clocks drive cyclic variations in many aspects of physiology, but some daily variations are evoked by periodic changes in the environment or sleep-wake state and associated behaviors, such as changes in posture, light levels, fasting or eating, rest or activity and social interactions; thus, it is often important to quantify the relative contributions of these factors. Yet, circadian rhythms and these evoked effects cannot be separated under typical 24-h day conditions, because circadian phase and the length of time awake or asleep co-vary. Nathaniel Kleitman's forced desynchrony (FD) protocol was designed to assess endogenous circadian rhythmicity and to separate circadian from evoked components of daily rhythms in multiple parameters. Under FD protocol conditions, light intensity is kept low to minimize its impact on the circadian pacemaker, and participants have sleep-wake state and associated behaviors scheduled to an imposed non-24-h cycle. The period of this imposed cycle, Τ, is chosen so that the circadian pacemaker cannot entrain to it and therefore continues to oscillate at its intrinsic period (τ, ~24.15 h), ensuring circadian components are separated from evoked components of daily rhythms. Here we provide detailed instructions and troubleshooting techniques on how to design, implement and analyze the data from an FD protocol. We provide two procedures: one with general guidance for designing an FD study and another with more precise instructions for replicating one of our previous FD studies. We discuss estimating circadian parameters and quantifying the separate contributions of circadian rhythmicity and the sleep-wake cycle, including statistical analysis procedures and an R package for conducting the non-orthogonal spectral analysis method that enables an accurate estimation of period, amplitude and phase.
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Affiliation(s)
- Wei Wang
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA, USA.
- Division of Sleep Medicine and Department of Medicine, Harvard Medical School, Boston, MA, USA.
| | - Robin K Yuan
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA, USA
- Division of Sleep Medicine and Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Jude F Mitchell
- Department of Brain and Cognitive Sciences, University of Rochester, Rochester, NY, USA
| | - Kirsi-Marja Zitting
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA, USA
- Division of Sleep Medicine and Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Melissa A St Hilaire
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA, USA
- Division of Sleep Medicine and Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - James K Wyatt
- Department of Psychiatry and Behavioral Sciences, Rush University Medical Center, Chicago, IL, USA
| | - Frank A J L Scheer
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA, USA
- Division of Sleep Medicine and Department of Medicine, Harvard Medical School, Boston, MA, USA
- Broad Institute, Cambridge, MA, USA
| | - Kenneth P Wright
- Sleep and Chronobiology Laboratory, Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, USA
| | - Emery N Brown
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, USA
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, USA
- Institute for Medical Engineering and Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA, USA
- Institute for Data Systems and Society, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Joseph M Ronda
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA, USA
- Division of Sleep Medicine and Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Elizabeth B Klerman
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA, USA
- Division of Sleep Medicine and Department of Medicine, Harvard Medical School, Boston, MA, USA
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
| | - Jeanne F Duffy
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA, USA
- Division of Sleep Medicine and Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Derk-Jan Dijk
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
- UK Dementia Research Institute Care Research and Technology Centre, Imperial College London and the University of Surrey, Guildford, UK
| | - Charles A Czeisler
- Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, MA, USA
- Division of Sleep Medicine and Department of Medicine, Harvard Medical School, Boston, MA, USA
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4
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Lok R, Woelders T, van Koningsveld MJ, Oberman K, Fuhler SG, Beersma DGM, Hut RA. Bright Light Increases Alertness and Not Cortisol in Healthy Men: A Forced Desynchrony Study Under Dim and Bright Light (I). J Biol Rhythms 2022; 37:403-416. [PMID: 35686534 PMCID: PMC9326799 DOI: 10.1177/07487304221096945] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Light-induced improvements in alertness are more prominent during nighttime than during the day, suggesting that alerting effects of light may depend on internal clock time or wake duration. Relative contributions of both factors can be quantified using a forced desynchrony (FD) designs. FD designs have only been conducted under dim light conditions (<10 lux) since light above this amount can induce non-uniform phase progression of the circadian pacemaker (also called relative coordination). This complicates the mathematical separation of circadian clock phase from homeostatic sleep pressure effects. Here we investigate alerting effects of light in a novel 4 × 18 h FD protocol (5 h sleep, 13 h wake) under dim (6 lux) and bright light (1300 lux) conditions. Hourly saliva samples (melatonin and cortisol assessment) and 2-hourly test sessions were used to assess effects of bright light on subjective and objective alertness (electroencephalography and performance). Results reveal (1) stable free-running cortisol rhythms with uniform phase progression under both light conditions, suggesting that FD designs can be conducted under bright light conditions (1300 lux), (2) subjective alerting effects of light depend on elapsed time awake but not circadian clock phase, while (3) light consistently improves objective alertness independent of time awake or circadian clock phase. Reconstructing the daily time course by combining circadian clock phase and wake duration effects indicates that performance is improved during daytime, while subjective alertness remains unchanged. This suggests that high-intensity indoor lighting during the regular day might be beneficial for mental performance, even though this may not be perceived as such.
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Affiliation(s)
- R. Lok
- Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands
- Current address: Department of Psychiatry and Behavioral Sciences, Stanford University, Palo Alto, California, USA
- University of Groningen, Leeuwarden, the Netherlands
| | - T. Woelders
- Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands
| | - M. J. van Koningsveld
- Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands
| | - K. Oberman
- Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands
| | - S. G. Fuhler
- Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands
| | - D. G. M. Beersma
- Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands
| | - R. A. Hut
- Chronobiology Unit, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands
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Orna T, Efrat B. Sleep Loss, Daytime Sleepiness, and Neurobehavioral Performance among Adolescents: A Field Study. Clocks Sleep 2022; 4:160-171. [PMID: 35323169 PMCID: PMC8947444 DOI: 10.3390/clockssleep4010015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 02/22/2022] [Accepted: 02/28/2022] [Indexed: 11/16/2022] Open
Abstract
The current study investigates the impact of sleep loss on neurobehavioral functioning and sleepiness in a natural setting among healthy adolescents. Fifty-nine adolescents (32 females) from grades 7 to 12 (mean age of 16.29 ± 1.86 years) participated in the study. All participants wore the actigraph for a continuous five to seven days, including school and nonschool days. Subjective sleepiness and neurobehavioral performance (using the psychomotor vigilance test and the digit symbol substitution test) were measured three times a day on two school days and one nonschool day. The results presented that sleep loss influenced subjective sleepiness reports, showing higher sleepiness scores following sleep loss than following sufficient night sleep. Neurobehavioral functioning across all measurements was also significantly worse following sleep loss. Furthermore, participants performed worse on weekday morning assessments than on assessments at other times of the day following sleep loss. These findings suggest that sleep loss in natural settings has a significant impact on neurobehavioral performance and subjective sleepiness. Our findings have essential implications for public policy on school schedules.
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Youngstedt SD, Elliott J, Patel S, Zi-Ching Mak N, Raiewski E, Malek E, Strong M, Mun CJ, Peters T, Madlol R, Tasevska N, Rasoul M, Nguyen C, Vargas Negrete KM, Adaralegbe AO, Sudalaimuthu S, Granholm D, Finch A, Eksambe A, Malready A, Parthasarathy S. Circadian acclimatization of performance, sleep, and 6-sulfatoxymelatonin using multiple phase shifting stimuli. Front Endocrinol (Lausanne) 2022; 13:964681. [PMID: 36465660 PMCID: PMC9710383 DOI: 10.3389/fendo.2022.964681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 10/03/2022] [Indexed: 11/18/2022] Open
Abstract
Misalignment between the environment and one's circadian system is a common phenomenon (e.g., jet lag) which can have myriad negative effects on physical and mental health, mental and physiological performance, and sleep. Absent any intervention, the circadian system adjusts only 0.5-1.0 h per day to a shifted light-dark and sleep-wake schedule. Bright light facilitates circadian adjustment, but in field studies, bright light is only modestly better than no stimulus. Evidence indicates that exercise and melatonin can be combined with bright light to elicit larger shifts but no study has combined all of these stimuli or administered them at the times that are known to elicit the largest effects on the circadian system. The aims of this study are to compare the effects of different treatments on circadian adjustment to simulated jet lag in a laboratory. Following 2 weeks of home recording, 36 adults will spend 6.5 consecutive days in the laboratory. Following an 8 h period of baseline sleep recording on the participant's usual sleep schedule on Night 1 (e.g., 0000-0800 h), participants will undergo a 26 h circadian assessment protocol involving 2 h wake intervals in dim light and 1 h of sleep in darkness, repeated throughout the 26 h. During this protocol, all urine voidings will be collected; mood, sleepiness, psychomotor vigilance, and pain sensitivity will be assessed every 3 h, forehead temperature will be assessed every 90 min, and anaerobic performance (Wingate test) will be tested every 6 h. Following, the circadian assessment protocol, the participant's sleep-wake and light dark schedule will be delayed by 8 h compared with baseline (e.g., 0800-1400 h), analogous to travelling 8 times zones westward. This shifted schedule will be maintained for 3 days. During the 3 days on the delayed schedule, participants will be randomized to one of 3 treatments: (1) Dim Red Light + Placebo Capsules, (2) Bright Light Alone, (3) Bright Light + Exercise + Melatonin. During the final 26 h, all conditions and measures of the baseline circadian protocol will be repeated. Acclimatization will be defined by shifts in circadian rhythms of aMT6s, psychomotor vigilance, Wingate Anaerobic performance, mood, and sleepiness, and less impairments in these measures during the shifted schedule compared with baseline. We posit that Bright Light Alone and Bright Light + Exercise + Melatonin will elicit greater shifts in circadian rhythms and less impairments in sleep, mood, performance, and sleepiness compared with Dim Red Light + Placebo Capsules. We also posit that Bright Light + Exercise + Melatonin will elicit greater shifts and less impairments than Bright Light Alone.
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Affiliation(s)
- Shawn D. Youngstedt
- Edson College of Nursing and Health Innovation, Arizona State University, Phoenix, AZ, United States
- Department of Medicine, University of Arizona, Tucson, AZ, United States
- *Correspondence: Shawn D. Youngstedt,
| | - Jeffrey Elliott
- Department of Psychiatry, University of California, San Diego, La Jolla, CA, United States
| | - Salma Patel
- Department of Medicine, University of Arizona, Tucson, AZ, United States
| | | | - Evan Raiewski
- Department of Psychology, California State University, San Marcos, CA, United States
| | - Elias Malek
- Department of Kinesiology and Nutrition Sciences, Univeristy of Nevada, Las Vegas, NV, United States
| | - Michael Strong
- Department of Medicine, University of Arizona, Tucson, AZ, United States
| | - Chung Jung Mun
- Edson College of Nursing and Health Innovation, Arizona State University, Phoenix, AZ, United States
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University, Baltimore, MD, United States
| | - Tyler Peters
- Department of Medicine, University of Arizona, Tucson, AZ, United States
| | - Remun Madlol
- Department of Medicine, University of Arizona, Tucson, AZ, United States
| | - Natasha Tasevska
- Edson College of Nursing and Health Innovation, Arizona State University, Phoenix, AZ, United States
| | - Massiullah Rasoul
- Department of Medicine, University of Arizona, Tucson, AZ, United States
| | - Cindy Nguyen
- Department of Medicine, University of Arizona, Tucson, AZ, United States
| | | | | | | | - Delaney Granholm
- Department of Medicine, University of Arizona, Tucson, AZ, United States
| | - Anastasia Finch
- Department of Medicine, University of Arizona, Tucson, AZ, United States
| | - Aryan Eksambe
- Department of Medicine, University of Arizona, Tucson, AZ, United States
| | - Anannya Malready
- Department of Medicine, University of Arizona, Tucson, AZ, United States
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Takaesu Y, Kanda Y, Nagahama Y, Shiroma A, Ishii M, Hashimoto T, Watanabe K. Delayed sleep-wake rhythm is associated with cognitive dysfunction, social dysfunction, and deteriorated quality of life in patients with major depressive disorder. Front Psychiatry 2022; 13:1022144. [PMID: 36419978 PMCID: PMC9677332 DOI: 10.3389/fpsyt.2022.1022144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 10/20/2022] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND The delayed sleep-wake phase is commonly observed in major depressive disorder (MDD) and thought to be associated with functional impairments. This study aimed to evaluate the relationship between the delayed sleep-wake phase, cognitive dysfunction, social dysfunction, and quality of life in patients with MDD. METHODS This cross-sectional design included 33 outpatients with MDD. Objective sleep-wake rhythm was assessed by actigraphy. Functional impairments were evaluated by the Japanese version of the Brief Assessment of Cognition in Schizophrenia (BACS-J), World Health Organization Disability Assessment Schedule (WHO-DAS), and Euro QOL 5 dimensions (EQ5D). RESULTS Actigraphic assessment of the delayed sleep-wake phase (midpoint of sleep) was significantly correlated with the composite score of the BACS-J (r = -0.489, p = 0.010), WHO-DAS score (r = 0.466, p = 0.014), and EQ5D score (r = 0.472, p = 0.013). No significant correlation was found between the other actigraphic sleep parameters (sleep latency, total sleep time, and sleep efficiency) and functional impairments. CONCLUSION Our study's results suggested that the delayed sleep-wake phase is associated with cognitive dysfunction, social dysfunction, and deteriorated quality of life in patients with MDD. Clinicians should pay attention to the sleep-wake rhythm in patients with MDD in clinical settings.
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Affiliation(s)
- Yoshikazu Takaesu
- Department of Neuropsychiatry, Graduate School of Medicine, University of the Ryukyus, Nishihara, Japan.,Department of Neuropsychiatry, Kyorin University School of Medicine, Tokyo, Japan
| | - Yuta Kanda
- Department of Neuropsychiatry, Kyorin University School of Medicine, Tokyo, Japan
| | - Yu Nagahama
- Department of Neuropsychiatry, Graduate School of Medicine, University of the Ryukyus, Nishihara, Japan
| | - Ayano Shiroma
- Department of Neuropsychiatry, Graduate School of Medicine, University of the Ryukyus, Nishihara, Japan
| | - Miho Ishii
- Department of Neuropsychiatry, Kyorin University School of Medicine, Tokyo, Japan
| | - Tasuku Hashimoto
- Department of Psychiatry, School of Medicine, International University of Health and Welfare, Narita, Japan.,Department of Psychiatry, Sodegaura Satsukidai Hospital, Sodegaura, Japan.,Department of Psychiatry, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Koichiro Watanabe
- Department of Neuropsychiatry, Kyorin University School of Medicine, Tokyo, Japan
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Stone JE, Phillips AJK, Chachos E, Hand AJ, Lu S, Carskadon MA, Klerman EB, Lockley SW, Wiley JF, Bei B, Rajaratnam SMW. In-person vs home schooling during the COVID-19 pandemic: Differences in sleep, circadian timing, and mood in early adolescence. J Pineal Res 2021; 71:e12757. [PMID: 34273194 PMCID: PMC8420593 DOI: 10.1111/jpi.12757] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 07/05/2021] [Accepted: 07/15/2021] [Indexed: 12/17/2022]
Abstract
During the COVID-19 pandemic, schools around the world rapidly transitioned from in-person to remote learning, providing an opportunity to examine the impact of in-person vs remote learning on sleep, circadian timing, and mood. We assessed sleep-wake timing using wrist actigraphy and sleep diaries over 1-2 weeks during in-person learning (n = 28) and remote learning (n = 58, where n = 27 were repeat assessments) in adolescents (age M ± SD = 12.79 ± 0.42 years). Circadian timing was measured under a single condition in each individual using salivary melatonin (Dim Light Melatonin Onset; DLMO). Online surveys assessed mood (PROMIS Pediatric Anxiety and Depressive Symptoms) and sleepiness (Epworth Sleepiness Scale - Child and Adolescent) in each condition. During remote (vs in-person) learning: (i) on school days, students went to sleep 26 minutes later and woke 49 minutes later, resulting in 22 minutes longer sleep duration (all P < .0001); (ii) DLMO time did not differ significantly between conditions, although participants woke at a later circadian phase (43 minutes, P = .03) during remote learning; and (iii) participants reported significantly lower sleepiness (P = .048) and lower anxiety symptoms (P = .006). Depressive symptoms did not differ between conditions. Changes in mood symptoms were not mediated by sleep. Although remote learning continued to have fixed school start times, removing morning commutes likely enabled adolescents to sleep longer, wake later, and to wake at a later circadian phase. These results indicate that remote learning, or later school start times, may extend sleep and improve some subjective symptoms in adolescents.
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Affiliation(s)
- Julia E. Stone
- Turner Institute for Brain and Mental HealthSchool of Psychological SciencesMonash UniversityClaytonVICAustralia
| | - Andrew J. K. Phillips
- Turner Institute for Brain and Mental HealthSchool of Psychological SciencesMonash UniversityClaytonVICAustralia
| | - Evangelos Chachos
- Turner Institute for Brain and Mental HealthSchool of Psychological SciencesMonash UniversityClaytonVICAustralia
| | - Anthony J. Hand
- Turner Institute for Brain and Mental HealthSchool of Psychological SciencesMonash UniversityClaytonVICAustralia
| | - Sinh Lu
- Turner Institute for Brain and Mental HealthSchool of Psychological SciencesMonash UniversityClaytonVICAustralia
| | - Mary A. Carskadon
- Department of Psychiatry & Human BehaviorChronobiology & Sleep Research LaboratoryEP Bradley HospitalThe Alpert Medical School of Brown UniversityProvidenceRIUSA
| | - Elizabeth B. Klerman
- Department of NeurologyMassachusetts General HospitalBostonMAUSA
- Division of Sleep and Circadian DisordersDepartments of Medicine and NeurologyBrigham and Women's HospitalBostonMAUSA
- Division of Sleep MedicineHarvard Medical SchoolBostonMAUSA
| | - Steven W. Lockley
- Division of Sleep and Circadian DisordersDepartments of Medicine and NeurologyBrigham and Women's HospitalBostonMAUSA
- Division of Sleep MedicineHarvard Medical SchoolBostonMAUSA
| | - Joshua F. Wiley
- Turner Institute for Brain and Mental HealthSchool of Psychological SciencesMonash UniversityClaytonVICAustralia
| | - Bei Bei
- Turner Institute for Brain and Mental HealthSchool of Psychological SciencesMonash UniversityClaytonVICAustralia
| | - Shantha M. W. Rajaratnam
- Turner Institute for Brain and Mental HealthSchool of Psychological SciencesMonash UniversityClaytonVICAustralia
- Division of Sleep and Circadian DisordersDepartments of Medicine and NeurologyBrigham and Women's HospitalBostonMAUSA
- Division of Sleep MedicineHarvard Medical SchoolBostonMAUSA
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9
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Fusilier AR, Davis JA, Paul JR, Yates SD, McMeekin LJ, Goode LK, Mokashi MV, Remiszewski N, van Groen T, Cowell RM, McMahon LL, Roberson ED, Gamble KL. Dysregulated clock gene expression and abnormal diurnal regulation of hippocampal inhibitory transmission and spatial memory in amyloid precursor protein transgenic mice. Neurobiol Dis 2021; 158:105454. [PMID: 34333153 PMCID: PMC8477442 DOI: 10.1016/j.nbd.2021.105454] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 07/19/2021] [Accepted: 07/27/2021] [Indexed: 11/27/2022] Open
Abstract
Patients with Alzheimer's disease (AD) often have fragmentation of sleep/wake cycles and disrupted 24-h (circadian) activity. Despite this, little work has investigated the potential underlying day/night disruptions in cognition and neuronal physiology in the hippocampus. The molecular clock, an intrinsic transcription-translation feedback loop that regulates circadian behavior, may also regulate hippocampal neurophysiological activity. We hypothesized that disrupted diurnal variation in clock gene expression in the hippocampus corresponds with loss of normal day/night differences in membrane excitability, synaptic physiology, and cognition. We previously reported disrupted circadian locomotor rhythms and neurophysiological output of the suprachiasmatic nucleus (the primary circadian clock) in Tg-SwDI mice with human amyloid-beta precursor protein mutations. Here, we report that Tg-SwDI mice failed to show day/night differences in a spatial working memory task, unlike wild-type controls that exhibited enhanced spatial working memory at night. Moreover, Tg-SwDI mice had lower levels of Per2, one of the core components of the molecular clock, at both mRNA and protein levels when compared to age-matched controls. Interestingly, we discovered neurophysiological impairments in area CA1 of the Tg-SwDI hippocampus. In controls, spontaneous inhibitory post-synaptic currents (sIPSCs) in pyramidal cells showed greater amplitude and lower inter-event interval during the day than the night. However, the normal day/night differences in sIPSCs were absent (amplitude) or reversed (inter-event interval) in pyramidal cells from Tg-SwDI mice. In control mice, current injection into CA1 pyramidal cells produced more firing during the night than during the day, but no day/night difference in excitability was observed in Tg-SwDI mice. The normal day/night difference in excitability in controls was blocked by GABA receptor inhibition. Together, these results demonstrate that the normal diurnal regulation of inhibitory transmission in the hippocampus is diminished in a mouse model of AD, leading to decreased daytime inhibition onto hippocampal CA1 pyramidal cells. Uncovering disrupted day/night differences in circadian gene regulation, hippocampal physiology, and memory in AD mouse models may provide insight into possible chronotherapeutic strategies to ameliorate Alzheimer's disease symptoms or delay pathological onset.
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Affiliation(s)
- Allison R Fusilier
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jennifer A Davis
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jodi R Paul
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Stefani D Yates
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Laura J McMeekin
- Department of Cell, Developmental, & Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA; Department of Neuroscience, Southern Research, Birmingham, AL 35205, USA
| | - Lacy K Goode
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Mugdha V Mokashi
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Natalie Remiszewski
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Thomas van Groen
- Department of Cell, Developmental, & Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Rita M Cowell
- Department of Cell, Developmental, & Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA; Department of Neuroscience, Southern Research, Birmingham, AL 35205, USA
| | - Lori L McMahon
- Department of Cell, Developmental, & Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Erik D Roberson
- Center for Neurodegeneration and Experimental Therapeutics, Alzheimer's Disease Center, Evelyn F. McKnight Brain Institute, Departments of Neurology and Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Karen L Gamble
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, USA.
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10
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Shochat T, Santhi N, Herer P, Dijk DJ, Skeldon AC. Sleepiness is a signal to go to bed: data and model simulations. Sleep 2021; 44:6276242. [PMID: 33991415 PMCID: PMC8503825 DOI: 10.1093/sleep/zsab123] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 04/19/2021] [Indexed: 12/16/2022] Open
Abstract
Study Objectives Assess the validity of a subjective measure of sleepiness as an indicator of sleep drive by quantifying associations between intraindividual variation in evening sleepiness and bedtime, sleep duration, and next morning and subsequent evening sleepiness, in young adults. Methods Sleep timing and sleepiness were assessed in 19 students in late autumn and late spring on a total of 771 days. Karolinska Sleepiness Scales (KSS) were completed at half-hourly intervals at fixed clock times starting 4 h prior to participants’ habitual bedtime, and in the morning. Associations between sleepiness and sleep timing were evaluated by mixed model and nonparametric approaches and simulated with a mathematical model for the homeostatic and circadian regulation of sleepiness. Results Intraindividual variation in evening sleepiness was very large, covering four or five points on the 9-point KSS scale, and was significantly associated with subsequent sleep timing. On average, a one point higher KSS value was followed by 20 min earlier bedtime, which led to 11 min longer sleep, which correlated with lower sleepiness next morning and the following evening. Associations between sleepiness and sleep timing were stronger in early compared to late sleepers. Model simulations indicated that the directions of associations between sleepiness and sleep timing are in accordance with their homeostatic and circadian regulation, even though much of the variance in evening sleepiness and details of its time course remain unexplained by the model. Conclusion Subjective sleepiness is a valid indicator of the drive for sleep which, if acted upon, can reduce insufficient sleep.
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Affiliation(s)
- Tamar Shochat
- Cheryl Spencer Department of Nursing, Faculty of Social Welfare and Health Sciences, University of Haifa, Haifa, Israel
| | - Nayantara Santhi
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom.,Department of Psychology, Faculty of Health and Life Sciences, Northumbria University, Newcastle Upon Tyne, United Kingdom
| | - Paula Herer
- Cheryl Spencer Department of Nursing, Faculty of Social Welfare and Health Sciences, University of Haifa, Haifa, Israel
| | - Derk-Jan Dijk
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom.,UK Dementia Research Institute, Care Research & Technology Centre, at Imperial College London and the University of Surrey, Guildford, United Kingdom
| | - Anne C Skeldon
- UK Dementia Research Institute, Care Research & Technology Centre, at Imperial College London and the University of Surrey, Guildford, United Kingdom.,Department of Mathematics, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, United Kingdom
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11
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Objectively measured sleep-wake patterns in patients with drug-resistant epilepsy - Interaction with quality of life and antiepileptic treatment. Epilepsy Behav 2020; 112:107316. [PMID: 33181903 DOI: 10.1016/j.yebeh.2020.107316] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 06/29/2020] [Accepted: 07/01/2020] [Indexed: 11/21/2022]
Abstract
RATIONALE Patients with epilepsy experience frequent episodes of fragmented sleep which may contribute to chronic sleep loss. Enhancing sleep patterns might lead to improved quality of life in these patients. Currently, unlike some other antiepileptic drugs (AEDs), there are no data on the effects of clobazam, a novel AED on sleep. Therefore, we tested the hypothesis that patients with epilepsy will have longer, more consolidated sleep after treatment with clobazam. METHODS In this prospective study, we included adults with drug-resistant epilepsy who were being considered for treatment with clobazam. Patients with known untreated moderate/severe sleep apnea or with major circadian rhythm disorders were excluded. We tested a set of the following subjective sleep measures: Pittsburgh Sleep Quality Inventory (PSQI), Epworth Sleepiness Scale (ESS), Karolinska Sleepiness Scale (KSS), Insomnia Severity Index (ISI), and Quality of Life in Epilepsy (QOLIE) prior to starting the treatment, as well as after achieving a stable clobazam dose. We also measured sleep pattern using wrist actigraphy - before starting therapy and after achieving stable dose. RESULTS A total of 12 participants completed all parts of the study. After treatment, a lower number of awakenings and less wake after sleep onset (WASO) were seen, as well as a lower number of seizures. Average pretreatment bedtime was 23:45, and average wake time was 8:24. A higher seizure frequency significantly correlated with all subjective sleep measures, as well as with a higher amount actigraphy measured WASO and less total sleep time (TST) measured both by sleep log and by actigraphy. Those with higher baseline WASO by actigraphy also had more depressive symptoms, worse quality of life, longer duration of epilepsy, and a higher seizure frequency. CONCLUSION Both objective and subjective sleep metrics correlate with depressive symptoms and quality of life. After treatment, there were fewer awakenings as well as fewer seizures.
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12
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Bessot N, Polyte R, Quesney M, Bulla J, Gauthier A. Diurnal gait fluctuations in single- and dual- task conditions. Chronobiol Int 2020; 37:836-844. [PMID: 32664758 DOI: 10.1080/07420528.2020.1773493] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Gait is one of the most basic movements, and walking activity accomplished in dual task conditions realistically represents daily life mobility. Much is known about diurnal variations of gait components such as muscle power, postural control, and attention. However, paradoxically only little is known about gait itself. The aim of this study was to analyze whether gait parameters show time-of-day fluctuation in simple and dual task conditions. Sixteen young subjects performed sessions at five specific hours (06:00, 10:00, 14:00, 18:00 and 22:00 h), performing a single (walking or counting) and a dual (walking and counting) task. When performing gait in dual task conditions, an additional cognitive task had to be carried out. More precisely, the participants had to count backwards from a two-digit random number by increments of three while walking. Spatio-temporal gait parameters and counting performance data were recorded for analysis. Walking speed significantly decreased, while stride length variability increased when the task condition switched from single to dual. In the single-task condition, diurnal variations were observed in both walking speed and counting speed. Walking speed was higher in the afternoon and in the evening (14:00 and 22:00 h) and lower in the morning (10:00 h). Counting speed was maximum at 10:00 and 14:00 h and minimum at 18:00 h. Nevertheless, no significant diurnal fluctuation was substanytiated in the dual task condition. These results confirm the existing literature about changes in gait between single and dual task conditions. A diurnal pattern of single-task gait could also be highlighted. Moreover, this study suggests that diurnal variations faded in complex dual task gait, when the cognitive load nearly reached its maximum. These findings might be used to reduce the risk for falls, especially of the elderly.
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Affiliation(s)
- N Bessot
- UNICAEN, INSERM, COMETE, GIP CYCERON, Normandie University , Caen, France
| | - R Polyte
- UNICAEN, INSERM, COMETE, GIP CYCERON, Normandie University , Caen, France
| | - M Quesney
- UNICAEN, INSERM, COMETE, GIP CYCERON, Normandie University , Caen, France
| | - J Bulla
- Department of Mathematics, University of Bergen , Bergen, Norway.,Department of Psychiatry and Psychotherapy, University Regensburg , Regensburg
| | - A Gauthier
- UNICAEN, INSERM, COMETE, GIP CYCERON, Normandie University , Caen, France
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13
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Bonmati-Carrion MA, Revell VL, Cook TJ, Welch TRE, Rol MA, Skene DJ, Madrid JA. Living Without Temporal Cues: A Case Study. Front Physiol 2020; 11:11. [PMID: 32116739 PMCID: PMC7020909 DOI: 10.3389/fphys.2020.00011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Accepted: 01/10/2020] [Indexed: 01/20/2023] Open
Abstract
Isolation from external time cues allows endogenous circadian rhythmicity to be demonstrated. In this study, also filmed as a television documentary, we assessed rhythmic changes in a healthy man time isolated in a bunker for 9 days/nights. During this period the lighting conditions were varied between: (1) self-selected light/dark cycle, (2) constant dim light, and (3) light/dark cycle with early wake up. A range of variables was assessed and related to the sleep-wake cycle, psychomotor and physical performance and clock-time estimation. This case study using modern non-invasive monitoring techniques emphasizes how different physiological circadian rhythms persist in temporal isolation under constant dim light conditions with different waveforms, free-running with a period (τ) between 24 and 25 h. In addition, a significant correlation between time estimation and mid-sleep time, a proxy for circadian phase, was demonstrated.
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Affiliation(s)
- Maria-Angeles Bonmati-Carrion
- Chronobiology Laboratory, Department of Physiology, University of Murcia, IMIB-Arrixaca, Espinardo, Spain.,Ciber de Fragilidad y Envejecimiento Saludable (CIBERFES), Madrid, Spain
| | - Victoria L Revell
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | | | | | - Maria-Angeles Rol
- Chronobiology Laboratory, Department of Physiology, University of Murcia, IMIB-Arrixaca, Espinardo, Spain.,Ciber de Fragilidad y Envejecimiento Saludable (CIBERFES), Madrid, Spain
| | - Debra J Skene
- Chronobiology, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Juan Antonio Madrid
- Chronobiology Laboratory, Department of Physiology, University of Murcia, IMIB-Arrixaca, Espinardo, Spain.,Ciber de Fragilidad y Envejecimiento Saludable (CIBERFES), Madrid, Spain
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14
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Network-based Responses to the Psychomotor Vigilance Task during Lapses in Adolescents after Short and Extended Sleep. Sci Rep 2019; 9:13913. [PMID: 31558730 PMCID: PMC6763427 DOI: 10.1038/s41598-019-50180-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 09/04/2019] [Indexed: 11/20/2022] Open
Abstract
Neuroimaging studies of the Psychomotor Vigilance Task (PVT) have revealed brain regions involved in attention lapses in sleep-deprived and well-rested adults. Those studies have focused on individual brain regions, rather than integrated brain networks, and have overlooked adolescence, a period of ongoing brain development and endemic short sleep. This study used functional MRI (fMRI) and a contemporary analytic approach to assess time-resolved peri-stimulus response of key brain networks when adolescents complete the PVT, and test for differences across attentive versus inattentive periods and after short sleep versus well-rested states. Healthy 14–17-year-olds underwent a within-subjects randomized protocol including 5-night spans of extended versus short sleep. PVT was performed during fMRI the morning after each sleep condition. Event-related independent component analysis (eICA) identified coactivating functional networks and corresponding time courses. Analysis of salient time course characteristics tested the effects of sleep condition, lapses, and their interaction. Seven eICA networks were identified supporting attention, executive control, motor, visual, and default-mode functions. Attention lapses, after either sleep manipulation, were accompanied by broadly increased response magnitudes post-stimulus and delayed peak responses in some networks. Well-circumscribed networks respond during the PVT in adolescents, with timing and intensity impacted by attentional lapses regardless of experimentally shortened or extended sleep.
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15
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Herz RS, Van Reen E, Barker DH, Hilditch CJ, Bartz AL, Carskadon MA. The Influence of Circadian Timing on Olfactory Sensitivity. Chem Senses 2019; 43:45-51. [PMID: 29045623 DOI: 10.1093/chemse/bjx067] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Olfactory sensitivity has traditionally been viewed as a trait that varies according to individual differences but is not expected to change with one's momentary state. Recent research has begun to challenge this position and time of day has been shown to alter detection levels. Links between obesity and the timing of food intake further raise the issue of whether odor detection may vary as a function of circadian processes. To investigate this question, 37 (21 male) adolescents (M age = 13.7 years) took part in a 28-h forced desynchrony (FD) protocol with 17.5 h awake and 10.5 h of sleep, for 7 FD cycles. Odor threshold was measured using Sniffin' Sticks 6 times for each FD cycle (total threshold tests = 42). Circadian phase was determined by intrinsic period derived from dim light melatonin onsets. Odor threshold showed a significant effect of circadian phase, with lowest threshold occurring on average slightly after the onset of melatonin production, or about 1.5○ (approximately 21:08 h). Considerable individual variability was observed, however, peak olfactory acuity never occurred between 80.5○ and 197.5○ (~02:22-10:10 h). These data are the first to show that odor threshold is differentially and consistently influenced by circadian timing, and is not a stable trait. Potential biological relevance for connections between circadian phase and olfactory sensitivity are discussed.
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Affiliation(s)
- Rachel S Herz
- Department of Psychiatry and Human Behavior, Alpert Medical School, Brown University, USA
| | - Eliza Van Reen
- Department of Psychiatry and Human Behavior, Alpert Medical School, Brown University, USA.,E.P. Bradley Hospital Sleep Research Laboratory, USA
| | - David H Barker
- Department of Psychiatry and Human Behavior, Alpert Medical School, Brown University, USA.,E.P. Bradley Hospital Sleep Research Laboratory, USA
| | | | | | - Mary A Carskadon
- Department of Psychiatry and Human Behavior, Alpert Medical School, Brown University, USA.,E.P. Bradley Hospital Sleep Research Laboratory, USA
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16
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Santhi N, Lazar AS, McCabe PJ, Lo JC, Groeger JA, Dijk DJ. Sex differences in the circadian regulation of sleep and waking cognition in humans. Proc Natl Acad Sci U S A 2016; 113:E2730-9. [PMID: 27091961 PMCID: PMC4868418 DOI: 10.1073/pnas.1521637113] [Citation(s) in RCA: 181] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The sleep-wake cycle and circadian rhythmicity both contribute to brain function, but whether this contribution differs between men and women and how it varies across cognitive domains and subjective dimensions has not been established. We examined the circadian and sleep-wake-dependent regulation of cognition in 16 men and 18 women in a forced desynchrony protocol and quantified the separate contributions of circadian phase, prior sleep, and elapsed time awake on cognition and sleep. The largest circadian effects were observed for reported sleepiness, mood, and reported effort; the effects on working memory and temporal processing were smaller. Although these effects were seen in both men and women, there were quantitative differences. The amplitude of the circadian modulation was larger in women in 11 of 39 performance measures so that their performance was more impaired in the early morning hours. Principal components analysis of the performance measures yielded three factors, accuracy, effort, and speed, which reflect core performance characteristics in a range of cognitive tasks and therefore are likely to be important for everyday performance. The largest circadian modulation was observed for effort, whereas accuracy exhibited the largest sex difference in circadian modulation. The sex differences in the circadian modulation of cognition could not be explained by sex differences in the circadian amplitude of plasma melatonin and electroencephalographic slow-wave activity. These data establish the impact of circadian rhythmicity and sex on waking cognition and have implications for understanding the regulation of brain function, cognition, and affect in shift-work, jetlag, and aging.
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Affiliation(s)
- Nayantara Santhi
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom;
| | - Alpar S Lazar
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom; Department of Clinical Neurosciences, University of Cambridge, Cambridge CB2 1TN, United Kingdom
| | - Patrick J McCabe
- Surrey Clinical Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom
| | - June C Lo
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom; Duke-NUS Medical School, Singapore 169857, Singapore
| | - John A Groeger
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom; Department of Psychology, University of Hull, Hull HU6 7RX, United Kingdom
| | - Derk-Jan Dijk
- Surrey Sleep Research Centre, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom
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