Publications
CamNtech Research Library
CamNtech products have been trusted by specialist researchers for over 25 years.
Our research library contains peer reviewed publications citing the use of our devices.
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Napping and circadian sleep-wake regulation during healthy aging
Study objectives Daytime napping is frequently reported among the older population and has attracted increasing attention due to its association with multiple health conditions. Here, we tested whether napping in the aged is associated with altered circadian regulation of sleep, sleepiness and vigilance performance. Methods Sixty healthy older individuals (mean age: 69y., 39 women) were […]
Related Product: MotionWatch
Publication Date: August 14, 2023
Multimodal investigation of melanopsin retinal ganglion cells in Alzheimer’s disease
Objective In Alzheimer’s disease (AD), the presence of circadian dysfunction is well-known and may occur early in the disease course. The melanopsin retinal ganglion cell (mRGC) system may play a relevant role in contributing to circadian dysfunction. In this study, we aimed at evaluating, through a multimodal approach, the mRGC system in AD at an […]
Related Product: MotionWatch
Publication Date: April 23, 2023
Risk Ahead: Actigraphy-based early-warning signals of increases in depressive symptoms during antidepressant discontinuation
Antidepressant discontinuation increases the risk of experiencing depressive symptoms. In a repeated single-subject design, we tested whether transitions in depression were preceded by increases in actigraphy-based critical-slowing-down-based early-warning signals (EWSs; variance, kurtosis, autocorrelation), circadian-rhythm-based indicators, and decreases in mean activity levels. Four months of data from 16 individuals with a transition in depression and nine […]
Related Product: MotionWatch
Publication Date: March 25, 2023
Rest-Activity Rhythm, Pain, and Motor Activity in Multiple Sclerosis
BACKGROUND Although the relationships among physical disability, mood disorders, and pain are well described in multiple sclerosis (MS), little is known about whether those symptoms are associated with sleep disturbances. METHODS Forty-six patients with MS experiencing pain participated. Sleep was indirectly measured by assessing rest-activity rhythm via actigraphy: interdaily stability, intradaily variability, and relative amplitude. […]
Related Product: MotionWatch
Publication Date: March 8, 2023
Internal desynchronization of circadian rhythms in 14 “free run” people living in a cave – Mission Deep Time
Objective Since the 1960s, it has been established that the endogenous rhythm of the circadian clock is approximately 24.5 h in the absence of any time donor. The objective of our study is to determine if a group of people living out of time will present the same rhythm as previously observed and if this […]
Related Product: MotionWatch
Publication Date: March 1, 2023
Phenotypic divergence in sleep and circadian cycles linked by affective state and environmental risk related to psychosis
Study Objectives Environmental cues influence circadian rhythm timing and neurochemicals involved in the regulation of affective behavior. How this interplay makes them a probable nonspecific risk factor for psychosis is unclear. We aimed to identify the relationship between environmental risk for psychosis and circadian timing phenotypes sampled from the general population. Methods Using an online […]
Related Product: MotionWatch
Publication Date: March 1, 2023
Effects of short naps during simulated night shifts on alertness and cognitive performance in young adults
While short daytime naps have been found to provide alertness and performance benefits without inducing sleep inertia, the effects of a similar napping strategy during nights shifts are largely unknown. This study examined the effects of a 20-min nap (scheduled at 2:00 a.m.) during night shifts among 16 participants (mean [SD] age 22.0 [1.08] years) who […]
Related Product: MotionWatch
Publication Date: January 26, 2023
Effects of Near-Infrared Light on Well-Being and Health in Human Subjects with Mild Sleep-Related Complaints: A Double-Blind, Randomized, Placebo-Controlled Study
In Western societies, people spend most of their waking hours indoors, exposing themselves to virtually no sunlight. Natural sunlight contains all visible and non-visible spectral characteristics of light. Both play key roles in human health and well-being. In this particular context, the non-visible near-infrared light has been shown to be beneficial for a wide range […]
Related Product: MotionWatch
Publication Date: December 29, 2022
Circadian phase advances in children during camping life according to the natural light-dark cycle
Background It is known that the circadian rhythm phase in adults can be advanced in a natural light-dark cycle without electrical lighting. However, the effect of advanced sleep-wake timing according to the natural light-dark cycle on children’s circadian phase is unclear. We investigated the effects of approximately 2 weeks of camping life with little access […]
Related Product: MotionWatch
Publication Date: December 16, 2022
Sleep–wake cycle and daytime sleepiness in patients with epilepsy after initiating perampanel as adjunctive therapy
Background Antiseizure medications (ASMs) may affect nocturnal sleep and daytime vigilance. Perampanel (PER), a third-generation ASM, showed to improve nocturnal sleep in patients with epilepsy (PWE). Although ASMs can have beneficial effects on nocturnal sleep and daytime sleepiness, no study investigated the effect of PER on both sleep–wake cycle and daytime sleepiness. Therefore, this study […]
Related Product: MotionWatch
Publication Date: December 8, 2022
Technological infrastructure, sleep, and rest-activity patterns in a Kaqchikel Maya community
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 […]
Related Product: MotionWatch
Publication Date: November 16, 2022
Compression of the optic chiasm is associated with permanent shorter sleep duration in patients with pituitary insufficiency
Objective Pituitary tumours that compress the optic chiasm are associated with long-term alterations in sleep–wake rhythm. This may result from damage to intrinsically photosensitive retinal ganglion cells (ipRGCs) projecting from the retina to the hypothalamic suprachiasmatic nucleus via the optic chiasm to ensure photoentrainment (i.e. synchronisation to the 24-h solar cycle through light). To test […]
Related Product: MotionWatch
Publication Date: November 4, 2022
Clock Genes Profiles as Diagnostic Tool in (Childhood) ADHD—A Pilot Study
Attention deficit hyperactivity disorder (ADHD) is a very common disorder in children and adults. A connection with sleep disorders, and above all, disorders of the circadian rhythm are the subject of research and debate. The circadian system can be represented on different levels. There have been a variety of studies examining 24-h rhythms at the […]
Related Product: MotionWatch
Publication Date: September 5, 2022
Changes in Circadian Rhythmicity during COVID-19 Pandemic Lockdowns
Background: For many people, the COVID-19 pandemic was an intrusion into their daily activities and their work and personal lives. Due to this pandemic, people were forced to spend their time mainly in their homes, which significantly reduced their activities. These restrictions have had a major impact on people, both in terms of their physical […]
Related Product: MotionWatch
Publication Date: September 2, 2022
Intake of l-serine before bedtime prevents the delay of the circadian phase in real life
Background It has been shown in laboratory experiments using human subjects that ingestion of the non-essential amino acid L-serine before bedtime enhances the advance of circadian phase induced by light exposure the next morning. In the present study, we tested the effect of ingestion of L-serine before bedtime on circadian phase in real life and […]
Related Product: MotionWatch
Publication Date: August 26, 2022
Daytime rest: Association with 24‐h rest‐activity cycles, circadian timing and cognition in older adults
Growing epidemiological evidence points toward an association between fragmented 24-h rest–activity cycles and cognition in the aged. Alterations in the circadian timing system might at least partially account for these observations. Here, we tested whether daytime rest (DTR) is associated with changes in concomitant 24-h rest probability profiles, circadian timing and neurobehavioural outcomes in healthy […]
Related Product: MotionWatch
Publication Date: July 29, 2022
MotionWatch 8 Wrist Activity and Light Analysis: from ambulatory recording toward real life monitoring
Background The Author’s interest is to apply physiological recordings for real-life, long-term and unsupervised monitoring as a complement to telemedicine and home care. This means the search for parameters that will be used to alert when some kind of support will be needed. To this end, the Author has recorded and published an appropriate Motionwatch8 […]
Related Product: MotionWatch
Publication Date: June 23, 2022
Bright Light Increases Alertness and Not Cortisol in Healthy Men: A Forced Desynchrony Study Under Dim and Bright Light
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 (
Related Product: MotionWatch
Publication Date: June 10, 2022
Associations between circadian misalignment and telomere length in BD: an actigraphy study
Background Life expectancy is significantly decreased in bipolar disorder (BD). This is associated with accelerated cellular aging which can be estimated by telomere length (TL). However, specific determinants of shorter TL in BD are under-explored. This study examines whether circadian misalignment (i.e. mismatch between preferred and actual phase of circadian activity rhythms) is associated with […]
Related Product: MotionWatch
Publication Date: May 27, 2022
Rest-Activity Circadian Rhythm and Light Exposure Using Wrist Actigraphy in ICU Patients
Actigraphy (ACTG) is easy to use and has proved reliable in non-critical populations of patients. It has been used to track circadian rest-activity cycles and to identify states of wakefulness and sleep [1]. A more recent study has found that ACTG have a moderate level of agreement with PSG in distinguishing between sleep and wakeful […]
Related Product: MotionWatch
Publication Date: April 18, 2022
Time Course of Motor Sleep Inertia Dissipation According to Age
Sleep inertia (SI) refers to a complex psychophysiological phenomenon observed after morning awakening that can be described as the gradual recovery of waking-like status after a night of sleep. The time course of SI dissipation in an everyday life condition is little studied. The present study aims to investigate the SI dissipation in motor activity, […]
Related Product: MotionWatch
Publication Date: March 23, 2022
Impact of sleep timing on attention, sleepiness, and sleep quality among real-life night shift workers with shift work disorder: a cross-over clinical trial
Study objectives: To examine the effect of sleep timing intervention on sleep quality, attention, and sleepiness at work among night shift workers with shift work disorder. Methods: We recruited 60 real-life night shift workers through advertisements to participate this cross-over clinical trial. Shift work disorder was confirmed with interview and sleep log. Participants were designated […]
Related Product: MotionWatch
Publication Date: March 10, 2022
Circadian and Sleep Modulation of Dreaming in Women with Major Depression
Growing evidence indicates an association between reduced dream recall and depressive symptomatology. Here, we tested the prediction that reduced dream recall in individuals experiencing major depressive disorder (MDD) is due to alterations in circadian and sleep processes. Nine young healthy women (20–31 years) and eight young unmedicated women (20–31 years) diagnosed with MDD underwent a […]
Related Product: MotionWatch
Publication Date: February 28, 2022
Do holidays change subjective sleep length or sleep debt in shift work disorder?
In shift work disorder (SWD), disturbed sleep acutely impairs employees’ recovery, but little attention has been paid to sleep during longer recovery periods. We examined how holidays affect self-estimated sleep length, sleep debt, and recovery in cases of SWD. Twenty-one shift workers with questionnaire-based SWD and nine reference cases without SWD symptoms completed a questionnaire […]
Related Product: MotionWatch
Publication Date: February 15, 2022
Chronic circadian disruption on a high-fat diet impairs glucose tolerance
Background Nearly 14% of Americans experience chronic circadian disruption due to shift work, increasing their risk of obesity, diabetes, and other cardiometabolic disorders. These disorders are also exacerbated by modern eating habits such as frequent snacking and consumption of high-fat foods. Methods We investigated the effects of recurrent circadian disruption (RCD) on glucose metabolism in […]
Related Product: MotionWatch
Publication Date: February 9, 2022
Cross-sectional study of intraocular cataract lens replacement, circadian rest-activity rhythms and sleep quality in older adults
Study objectives: Age-related cataract decreases light transmission at the most sensitive spectrum for circadian photoentrainment, with negative ramifications for human health. Here, we assessed whether intraocular lens replacement (IOL) in older patients with previous cataract was associated with increased stability and amplitude of circadian rest-activity rhythms, and sleep quality. Methods: Our cross-sectional study included sixteen […]
Related Product: MotionWatch
Publication Date: January 27, 2022
An exploratory study of associations between sleep timing variability and cardiometabolic health in middle-aged adults with type 2 diabetes mellitus
Sleep is increasingly recognised as an important risk factor for metabolic disease, and as an important influence on severity in established metabolic disease. Recent evidence suggests that sleep timing variability (the day-to-day fluctuations of sleep timing) may be an important factor in metabolic diseases such as type 2 diabetes mellitus. In the current study, we […]
Related Product: MotionWatch
Publication Date: January 11, 2022
Effects of Circadian Phase Tailored Light Therapy on Sleep, Mood, and Cognition in Alzheimer’s Disease: Preliminary Findings in a Pivotal Study
It is shown that the circadian system is affected in patients with Alzheimer’s disease (AD) even at an early stage of the disease and that such dysfunction may be detrimental to sleep, mood, and cognitive functioning. Light is a strong central modulator of the circadian rhythms and is potentially beneficial to mood and cognitive functioning […]
Related Product: MotionWatch
Publication Date: January 6, 2022
More than sleep and wake disturbances: an actigraphic study showing the sleep-wake pattern dysregulation in epilepsy
Objective This study aimed to assess the sleep-wake pattern in patients with epilepsy compared to controls. Methods Patients with epilepsy and controls underwent a 14-day actigraphic recording to evaluate the rest-activity cycle. A sleep medicine interview was performed to exclude conditions interfering with the sleep-wake cycle in both patients and controls. Patients presenting seizures during […]
Related Product: MotionWatch
Publication Date: November 30, 2021
The influence of integrative lighting on sleep and cognitive functioning of shift workers during the morning shift in an assembly plant
It is well known that exposure to light at the right time of the day is important to synchronise our circadian rhythm and enhance cognitive functioning. There is, however, a lack of field studies investigating which lighting characteristics are necessary to improve sleep and cognitive functioning. A controlled field study with 80 shift workers was […]
Related Product: MotionWatch
Publication Date: November 11, 2021
Extracting Circadian and Sleep Parameters from Longitudinal Data in Schizophrenia for the Design of Pragmatic Light Interventions
Sleep and circadian rhythm dysfunction is prevalent in schizophrenia, is associated with distress and poorer clinical status, yet remains an under-recognized therapeutic target. The development of new therapies requires the identification of the primary drivers of these abnormalities. Understanding of the regulation of sleep-wake timing is now sufficiently advanced for mathematical model-based analyses to identify […]
Related Product: MotionWatch
Publication Date: November 10, 2021
How Smart Is It to Go to Bed with the Phone? The Impact of Short-Wavelength Light and Affective States on Sleep and Circadian Rhythms
Previously, we presented our preliminary results (N = 14) investigating the effects of short-wavelength light from a smartphone during the evening on sleep and circadian rhythms (Höhn et al., 2021). Here, we now demonstrate our full sample (N = 33 men), where polysomnography and body temperature were recorded during three experimental nights and subjects read […]
Related Product: MotionWatch
Publication Date: October 28, 2021
The actigraphic documentation of circadian sleep-wake rhythm dysregulation in Myotonic Dystrophy Type 1
Study Objectives The present study aimed at identifying the sleep-wake rhythm in patients with myotonic dystrophy type 1 (DM1) compared to healthy controls. Methods Patients with genetic diagnosis of DM1 and healthy controls underwent a 7-day actigraphic recording and filled out a daily sleep diary to evaluate the sleep-wake rhythm. All participants underwent a physical […]
Related Product: MotionWatch
Publication Date: October 15, 2021
Diurnal variations of resting-state fMRI data: A graph-based analysis
Circadian rhythms synchronize a variety of physiological processes ranging from neural activity and hormone secretion to sleep cycles and feeding habits. Despite significant diurnal variation, time-of-day (TOD) is rarely recorded or analyzed in human brain research. Moreover, sleep-wake patterns, diurnal preferences, and daytime alertness vary across individuals, known as sleep chronotypes. Here, we performed graph-theory […]
Related Product: MotionWatch
Publication Date: October 12, 2021
Event-related desynchronization in motor imagery with EEG neurofeedback in the context of declarative interference and sleep
Motor imagery (MI) in combination with neurofeedback (NF) is a promising supplement to facilitate the acquisition of motor abilities and the recovery of impaired motor abilities following brain injuries. However, the ability to control MI NF is subject to a wide range of inter-individual variability. A substantial number of users experience difficulties in achieving good […]
Related Product: MotionWatch
Publication Date: October 12, 2021
Effects of the selective orexin-2 receptor antagonist JNJ-48816274 on sleep initiated in the circadian wake maintenance zone: a randomised trial
The effects of orexinergic peptides are diverse and are mediated by orexin-1 and orexin-2 receptors. Antagonists that target both receptors have been shown to promote sleep initiation and maintenance. Here, we investigated the role of the orexin-2 receptor in sleep regulation in a randomised, double-blind, placebo-controlled, three-period crossover clinical trial using two doses (20 and […]
Related Product: MotionWatch
Publication Date: October 9, 2021
Rest activity rhythms characteristics of breast cancer women following endocrine therapy
Rest-activity rhythm (RAR) disruptions are frequently associated with chemotherapy in breast cancer (BC), but they are less known in BC with endocrine therapy (ET). The aim of this ancillary study was to characterize the RAR and estimated sleep characteristics from actigraphy in BC patients either treated (ET+) or untreated with ET (ET−), compared to healthy […]
Related Product: MotionWatch
Publication Date: October 8, 2021
A Multidisciplinary Prematurity Research Cohort Study
Background Worldwide, 10% of babies are born preterm, defined as a live birth before 37 weeks of gestation. Preterm birth is the leading cause of neonatal death, and survivors face lifelong risks of adverse outcomes. New approaches with large sample sizes are needed to identify strategies to predict and prevent preterm birth. The primary aims […]
Related Product: MotionWatch
Publication Date: September 29, 2021
Effects of 2-hour nighttime nap on melatonin concentration and alertness during 12-hour simulated night work
A nighttime nap is expected to mitigate melatonin suppression during night work by blocking light input to the retina, but it is unclear. In the present study, we investigated the effects of a nap break on melatonin level, subjective sleepiness, and vigilance performance during simulated night work. Eleven healthy young males (mean ± SD age: […]
Related Product: MotionWatch
Publication Date: September 27, 2021
Are we still in the dark? A systematic review on personal daily light exposure, sleep-wake rhythm, and mood in healthy adults from the general population
Insufficient light exposure is assumed to be related to a wide array of health problems, though few studies focus on the role of whole-day light exposure in the habitual setting in the development of these health problems. The current review aims to describe the association between personal light exposure in the habitual setting and sleep-wake […]
Related Product: MotionWatch
Publication Date: August 19, 2021
Circadian rhythm and quality of life in older adults
Sleep is critical to physical and mental health for people of all ages, but older adults are particularly vulnerable to the consequences of poor sleep health. The purpose of this pilot study was to explore patterns of sleep and the relationships between circadian rhythm disorders and quantity of life in 34 community-dwelling older adults. Participants […]
Related Product: MotionWatch
Publication Date: June 17, 2021
Time-of-day effects on objective and subjective short-term memory task performance
The time-of-day along with the synchrony effect (better performance at optimal times of the day according to the chronotype) on the cognitive performance has been well established in previous research. This influence is mediated by both circadian and homeostatic processes consistent with the Borbély two-process model. This experiment focused on the objective and subjective performance […]
Related Product: MotionWatch
Publication Date: June 14, 2021
Efficacy of early warning signals and spectral periodicity for predicting transitions in bipolar patients: An actigraphy study
Early-warning signals (EWS) have been successfully employed to predict transitions in research fields such as biology, ecology, and psychiatry. The predictive properties of EWS might aid in foreseeing transitions in mood episodes (i.e. recurrent episodes of mania and depression) in bipolar disorder (BD) patients. We analyzed actigraphy data assessed during normal daily life to investigate […]
Related Product: MotionWatch
Publication Date: June 7, 2021
MotionWatch 8 Wrist Actimetry Data Analysis: from ambulatory recording to real life monitoring
On the National Sleep Research Resource (NSRR) platform, there’s a year’s worth in real-life wrist actigraphy data using a Motionwatch8. The data analysis suggested in this paper reveals a data structure that allows the design of parameters to be used in real life monitoring and may drive the developments of devices. The analysis is totally […]
Related Product: MotionWatch
Publication Date: May 13, 2021
Different Circadian Rest-Active Rhythms in Kleine-Levin Syndrome: A prospective and case-control study
Study objectives Kleine-Levin-syndrome (KLS) is a rare recurrent hypersomnia. Our study aimed at monitoring the movements of patients with KLS using actigraphy and evaluating their circadian rhythm. Methods Twenty young patients with KLS and 14 age-matched controls were recruited. Each individual wore an actigraphy for more than 6 months to monitor at least two attacks. […]
Related Product: MotionWatch
Publication Date: April 14, 2021
Sleep deprivation therapy to reset the circadian pacemaker in a non-24-hour sleep-wake disorder: a case report
Non-24-hour sleep-wake disorder (N24SWD) is one of several chronic circadian rhythm sleep-wake disorders (CRSWDs). It is defined as progressive daily shifts in sleep onset and wake times. It mainly affects sight-impaired persons, is relatively rare in sighted patients, and is difficult to treat, with no guidelines. We report a case of N24SWD in a sighted […]
Related Product: MotionWatch
Publication Date: April 1, 2021
Quantifying Circadian Aspects of Mobility-Related Behavior in Older Adults by Body-Worn Sensors—An “Active Period Analysis”
Disruptions of circadian motor behavior cause a significant burden for older adults as well as their caregivers and often lead to institutionalization. This cross-sectional study investigates the association between mobility-related behavior and subjectively rated circadian chronotypes in healthy older adults. The physical activity of 81 community-dwelling older adults was measured over seven consecutive days and […]
Related Product: MotionWatch
Publication Date: March 18, 2021
Sex Differences in Rest-Activity Circadian Rhythm in Patients With Metabolic Syndrome
Rest-Activity circadian Rhythm (RAR) can be used as a marker of the circadian timing system. Recent studies investigated the relationship between irregular circadian rhythms and cardiovascular risk factors such as hypertension, obesity, and dyslipidemia. These factors are related to the Metabolic Syndrome (MS), a clustering of metabolic risk factors that increases the risk of several […]
Related Product: MotionWatch
Publication Date: March 18, 2021
Weekly, seasonal and chronotype‐dependent variation of Dim‐Light Melatonin Onset
In humans, the most important zeitgeber for entrainment is light. Laboratory studies have shown that meaningful changes in light exposure lead to phase shifts in markers of the circadian clock. In natural settings, light is a complex signal varying with external conditions and individual behaviors; nonetheless, phase of entrainment is assumed to be fairly stable. […]
Related Product: MotionWatch
Publication Date: February 20, 2021
Temporal organisation of the brain’s intrinsic motor network: The relationship with circadian phenotype and motor performance
Background Functional connectivity (FC) of the motor network (MN) is often used to investigate how intrinsic properties of the brain are associated with motor abilities and performance. In addition, the MN is a key feature in clinical work to map the recovery after stroke and aid the understanding of neurodegenerative disorders. Time of day variation […]
Related Product: MotionWatch
Publication Date: February 9, 2021
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