Shantha M W Rajaratnam's research while affiliated with Monash University (Australia) and other places
What is this page?
This page lists the scientific contributions of an author, who either does not have a ResearchGate profile, or has not yet added these contributions to their profile.
It was automatically created by ResearchGate to create a record of this author's body of work. We create such pages to advance our goal of creating and maintaining the most comprehensive scientific repository possible. In doing so, we process publicly available (personal) data relating to the author as a member of the scientific community.
If you're a ResearchGate member, you can follow this page to keep up with this author's work.
If you are this author, and you don't want us to display this page anymore, please let us know.
It was automatically created by ResearchGate to create a record of this author's body of work. We create such pages to advance our goal of creating and maintaining the most comprehensive scientific repository possible. In doing so, we process publicly available (personal) data relating to the author as a member of the scientific community.
If you're a ResearchGate member, you can follow this page to keep up with this author's work.
If you are this author, and you don't want us to display this page anymore, please let us know.
Publications (225)
Study objectives:
To explore potential relationships and longitudinal changes in sleep and mental health in recruit paramedics over the first 6-months of work, and whether sleep disturbances pre-emergency work predict future mental health outcomes.
Methods:
Participants (N=101, 52% female, Mage=26 years) completed questionnaires prior to (baseli...
Objectives: Mental fitness is increasingly considered a key component of an athlete’s competitive arsenal. Active domains of mental fitness include cognitive fitness, sleep, and mental health; and these domains can differ between men and women athletes. Our study investigated the associations of cognitive fitness and gender to sleep and mental heal...
Objectives:
Studies have found associations between occupational burnout symptoms and reduced engagement with healthy behaviours. We sought to characterise demographic, employment and sleep characteristics associated with occupational burnout symptoms, and to evaluate their relationships with adherence to COVID-19 prevention behaviours (mask usage...
Study Objectives
Insomnia is common in the general population and is diagnosed based on self-reported sleep complaints. There is often discrepancy between objectively recorded and self-reported sleep (sleep-wake state discrepancy), especially in individuals with insomnia. Although sleep-wake state discrepancy is well-documented in the literature, i...
Objective
This meta-analysis of randomized controlled trials (RCTs) evaluates if treating sleep disturbances improves cognitive function over at least 12 weeks.
Methods
Multiple data sources were searched until November 1, 2021. RCTs were included if they examined the effect of an intervention (behavioral or medical) on sleep and cognition in an a...
Studies have consistently shown crowds contribute to home advantage in the National Basketball Association (NBA) by inspiring home team effort, distracting opponents, and influencing referees. Quantifying the effect of crowds is challenging, however, due to potential co-occurring drivers of home advantage (e.g., travel, location familiarity). Our a...
Human circadian, neuroendocrine, and neurobehavioral responses to light are mediated primarily by melanopsin-containing intrinsically-photosensitive retinal ganglion cells (ipRGCs) but they also receive input from visual photoreceptors. Relative photoreceptor contributions are irradiance- and duration-dependent but results for long-duration light e...
Drowsy driving is a major cause of fatal and serious injury motor vehicle accidents. The inability objectively to assess drowsiness has hindered the assessment of fitness to drive and the development of drowsy driving regulations. This study evaluated whether spontaneous eye blink parameters measured briefly pre‐ and post‐drive could be used to det...
During the early stages of the COVID-19 pandemic, use of preventive behaviors was associated with perceived risk for contracting SARS-CoV-2 infection (1,2). Over time, perceived risk has declined along with waning COVID-19-related media coverage (3,4). The extent to which communities continue to be aware of local COVID-19 transmission levels and ar...
Objectives
Depression and anxiety are prominent in paramedics, as is the prevalence of shift work disorder (SWD), a circadian sleep condition comorbid with mental health disorders. However, the role of mental health risk factors for SWD is largely unknown. This study investigated whether mental health levels in recruit paramedics before shift work...
Study objectives
While drowsiness contributes to 20% of heavy vehicle crashes, the impact of work schedules on heavy vehicle driver (HVD) drowsiness is unclear. This study explored the impact of work schedules on drowsiness (measured by infrared oculography) in HVDs.
Method
Work and drowsiness monitoring (Optalert, Australia) of ten HVDs, aged 37–...
Background
Insomnia symptoms are common during the postpartum period, yet interventions remain scarce. This trial aimed to simultaneously examine the efficacy of cognitive behavioural therapy (CBT) and light dark therapy (LDT), targeting different mechanisms, against treatment-as-usual (TAU), in reducing maternal postpartum insomnia symptoms.
Meth...
Objectives: This study assessed the associations between parent intent to have their child receive the COVID-19 vaccination, and demographic factors and various child activities, including attendance at in-person education or childcare. Methods: Persons undergoing COVID-19 testing residing in Minnesota and Los Angeles County, California with childr...
We conducted a retrospective observational study using remote wearable and mobile application data to evaluate whether US public holidays or Daylight Saving Time transitions were associated with significant changes in sleep behaviors, including sleep duration, sleep onset and offset, and the consistency of sleep timing, as well as changes in the po...
The Antarctic environment presents extreme variation in the natural light‐dark cycle which can cause variability in the alignment of the circadian pacemaker with the timing of sleep, causing sleep disruption and impaired mood and performance. This study assessed the incidence of circadian misalignment and the consequences for sleep, cognition and p...
Restorative sleep is a commonly used term but a poorly defined construct. Few studies have assessed restorative sleep in nationally representative samples. We convened a panel of 7 expert physicians and researchers to evaluate and enhance available measures of restorative sleep. We then developed the revised Restorative Sleep Questionnaire (REST-Q)...
Objectives: Elite athletes are often required to travel across time zones for national and international competitions, causing frequent jet lag. The aim of this study was to examine whether the direction of travel-related jet lag is associated with performance in the National Basketball Association (NBA), and if so, to explore potential mechanisms....
Background:
During adolescence, sleep and circadian timing shift later, contributing to restricted sleep duration and irregular sleep-wake patterns. The association of these developmental changes in sleep and circadian timing with cognitive functioning, and consequently academic outcomes, has not been examined prospectively. The role of ambient li...
This study examined the impact of first and second night shift work on sleep and performance in mining haul truck drivers. Sleep-wake patterns were monitored using wrist actigraphy. The Karolinska Sleepiness Scale (KSS), Psychomotor Vigilance Test (PVT) and a truck simulator were administered at the start and end of the first (N1) or second (N2) ni...
This article presents some of the principal ways that sleepiness (“fatigue,” “drowsiness”) and impaired human performance occurring as a consequence of circadian rhythm sleep-wake disorders (CRSWDs) can interact with the law, including implications related to civil and criminal liability and legal structures governing the workplace (e.g., governmen...
Study objectives:
While insomnia and sleepiness symptoms are common in shift workers, 20-30% experience more severe symptoms and meet the criteria for shift work disorder (SWD). SWD can lead to impairments in cognitive function, physical and mental health, and reduced productivity and increased risk of workplace injury. The aim of this study was t...
Diabetes affects approximately one in 10 persons in the United States† and is a risk factor for severe COVID-19 (1), especially when a patient's diabetes is not well managed (2). The extent to which the COVID-19 pandemic has affected diabetes care and management, and whether this varies across age groups, is currently unknown. To evaluate access to...
Impaired driving performance due to sleep loss is a major contributor to motor-vehicle crashes, fatalities, and serious injuries. As on-road, fully-instrumented studies of drowsy driving have largely focused on young drivers, we examined the impact of sleep loss on driving performance and physiological drowsiness in both younger and older drivers o...
Objective
The Psychomotor Vigilance Test (PVT) is considered the gold standard for detecting sleep loss and circadian misalignment related changes in performance in laboratory and field settings. This short 3-, 5- or 10-min test appraises an individual’s sustained vigilant attention on a visual stimulus through reaction time, false starts and perfo...
Background and Objectives: Fatigue and sleep disturbance negatively impact quality of life following brain injury and there are no established treatments. Building on research showing efficacy of blue light therapy delivered via a lightbox in reducing fatigue and daytime sleepiness after traumatic brain injury (TBI), this paper describes the develo...
Adults with disabilities, a group including >25% of U.S. adults (1), experience higher levels of mental health and substance use conditions and lower treatment rates than do adults without disabilities* (2,3). Survey data collected during April-September 2020 revealed elevated adverse mental health symptoms among adults with disabilities (4) compar...
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) an...
Abstract Background and objectives Fatigue and sleep disturbance are debilitating problems following brain injury and there are no established treatments. Building on demonstrated efficacy of blue light delivered via a lightbox in reducing fatigue and daytime sleepiness after TBI, this study evaluated the efficacy of a novel in-home light intervent...
Background: Fatigue and sleep disturbance are common and debilitating problems after brain injury. Light therapy shows promise as a potential treatment. We conducted a trial of in-home light therapy to alleviate fatigue and sleep disturbance. The aim of the current study was to identify factors moderating treatment response.
Methods: Participants w...
Background:
An inadequate rest break between shifts may contribute to driver sleepiness. This study assessed whether extending the major rest break between shifts from 7-hours (Australian industry standard) to 11-hours, improved drivers' sleep, alertness and naturalistic driving performance.
Methods:
17 heavy vehicle drivers (16 male) were recru...
Early during the COVID-19 pandemic, nearly two thirds of unpaid caregivers of adults reported adverse mental or behavioral health symptoms, compared with approximately one third of noncaregivers† (1). In addition, 27% of parents of children aged <18 years reported that their mental health had worsened during the pandemic (2). To examine mental heal...
Study Objectives
The study aimed to, for the first time, (i) compare sleep, circadian phase, and alertness of Intensive Care Unit (ICU) nurses working rotating shifts with those predicted by a model of arousal dynamics; and (ii) investigate how different environmental constraints affect predictions and agreement with data.
Methods
The model was us...
Aims
Markedly elevated adverse mental health symptoms were widely observed early in the coronavirus disease-2019 (COVID-19) pandemic. Unlike the U.S., where cross-sectional data indicate anxiety and depression symptoms have remained elevated, such symptoms reportedly declined in the U.K., according to analysis of repeated measures from a large-scal...
Methods for predicting circadian phase have been developed for healthy individuals. It is unknown whether these methods generalize to clinical populations, such as delayed sleep–wake phase disorder (DSWPD), where circadian timing is associated with functional outcomes. This study evaluated two methods for predicting dim light melatonin onset (DLMO)...
Importance
SARS-CoV-2 containment is estimated to require attainment of high (>80%) post-infection and post-vaccination population immunity.
Objective
To assess COVID-19 vaccine intentions among US adults and their children, and reasons for vaccine hesitancy among potential refusers.
Design
Internet-based surveys were administered cross-sectionally...
Background
Governments worldwide recommended unprecedented measures to contain the coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). As pressure mounted to scale back measures, understanding public priorities was critical. We assessed initial public adherence with and support for s...
Study objectives:
A recent clinical trial demonstrated that melatonin treatment was effective in improving self-perceived sleep quality in patients with traumatic brain injury (TBI); however, it remains unclear which patients benefited from melatonin treatment. To that end, findings from the clinical trial were re-examined to identify possible pre...
We aimed to investigate the impact of the Wake Maintenance Zone (WMZ) on measures of drowsiness, attention, and subjective performance under rested and sleep deprived conditions. We studied 23 healthy young adults (18 males; mean age = 25.41 ± 5.73 years) during 40 hr of total sleep deprivation under constant routine conditions. Participants comple...
Polyphasic sleep is the practice of distributing multiple short sleep episodes across the 24-hour day rather than having one major and possibly a minor (“nap”) sleep episode each day. While the prevalence of polyphasic sleep is unknown, anecdotal reports suggest attempts to follow this practice are common, particularly among young adults. Polyphasi...
This survey study compared patterns of mental health concerns, substance use, and suicidal ideation during June and September 2020 of the COVID-19 pandemic and examined at-risk demographic groups.
Objectives
To estimate the prevalence of unpaid caregiving during the coronavirus disease 2019 (COVID-19) pandemic, and to identify factors associated with adverse mental health symptoms, substance use, and suicidal ideation in this population, which provides critical support in health care systems by providing care to older adults and those with c...
The global coronavirus 19 (COVID-19) pandemic and associated lockdown restrictions resulted in the majority of sports competitions around the world being put on hold. This includes the National Basketball Association, the UEFA Champions League, Australian Football League, the Tokyo 2020 Olympic Games, and regional competitions. The mitigation strat...
Aims
Markedly elevated adverse mental health symptoms were widely observed early in the coronavirus disease 2019 (COVID-19) pandemic. Unlike the U.S., where cross-sectional data indicate anxiety and depression symptoms have remained elevated, such symptoms reportedly declined in the U.K., according to analysis of repeated measures from a largescale...
Background: Symptoms of insomnia are common in new mothers and have been associated with a range of negative maternal and child outcomes. Despite this, interventions to improve maternal postpartum sleep remain scarce. Cognitive Behavioural Therapy (CBT) and Light Dark Therapy (LDT) represent two promising interventions for insomnia symptoms and ass...
Frequent hand hygiene, including handwashing with soap and water or using a hand sanitizer containing ≥60% alcohol when soap and water are not readily available, is one of several critical prevention measures recommended to reduce the spread of SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19).* Previous studies identified demog...
Temporary disruptions in routine and nonemergency medical care access and delivery have been observed during periods of considerable community transmission of SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19) (1). However, medical care delay or avoidance might increase morbidity and mortality risk associated with treatable and p...
The coronavirus disease 2019 (COVID-19) pandemic has been associated with mental health challenges related to the morbidity and mortality caused by the disease and to mitigation activities, including the impact of physical distancing and stay-at-home orders.* Symptoms of anxiety disorder and depressive disorder increased considerably in the United...
Knowledge of circadian phase is critical for timing interventions for circadian rhythm disorders, medications, or predicting alertness. Current gold-standard measures of circadian phase are impractical for continuous or real-time tracking. Mathematical modeling offers an alternative, whereby ambulatory monitoring of environmental, behavioral, and/o...
SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19), is thought to be transmitted mainly by person-to-person contact (1). Implementation of nationwide public health orders to limit person-to-person interaction and of guidance on personal protective practices can slow transmission (2,3). Such strategies can include stay-at-home ord...
Introduction
The ultimate goal in the sports world is achieving optimal health and continuous high-level performance through an adequate balance of training load and recovery e.g. rehab, nutrition, well being and sleep. Athletes often encounter situations that negatively impact their ability to sleep well, disrupt their biological rhythms and incre...
Objectives
This study examined the influence of a wrist-worn heart rate drowsiness detection device on heavy vehicle driver safety and sleep and its ability to predict driving events under naturalistic conditions.
Design
Prospective, non-randomized trial.
Setting
Naturalistic driving in Malaysia.
Participants
Heavy vehicle drivers in Malaysia we...
Sleepiness is a major contributor to motor vehicle crashes and shift workers are particularly vulnerable. There is currently no validated objective field-based measure of sleep-related impairment prior to driving. Ocular parameters are promising markers of continuous driver alertness in laboratory and track studies, however their ability to determi...
Objectives
To examine associations between shift work characteristics and schedules on burnout in police and whether sleep duration and sleepiness were associated with burnout.
Methods
Police officers (n=3140) completed the Maslach Burnout Inventory (emotional exhaustion, depersonalisation, personal accomplishment) and self-reported shift schedule...
Study objectives:
Women in the luteal phase of the menstrual cycle exhibit better cognitive performance overnight than women in the follicular phase, although the mechanism is unknown. Given the link between core body temperature (CBT) and performance, one potential mechanism is the thermoregulatory role of progesterone (P4), estradiol (E2), and t...
A high proportion (20%–30%) of shift workers experience Shift Work Disorder (SWD), characterized by chronic sleepiness and/or insomnia associated with work schedules. The reasons for individual variation in shift work tolerance are not well understood, however. The aim of this study was to identify individual factors that contribute to the risk of...
To examine the relationship between heavy vehicle driver fatigue, time of day and shift-start times, data from an automatic driver monitoring system (Guardian, Seeing Machines) was assessed for over 140,000 shifts across four different operator companies. Results revealed that of the 2290 fatigue events detected, 63% occurred during the night time...
This article is a commentary on our newly published paper in the Journal of Clinical Sleep Medicine.
The Australian National Road Safety Strategy 2011–2020 framed a 19-point action plan
targeting a 30% reduction in road deaths by 2020. In achieving a 9% reduction to date,
it is likely to fail this target. Sleep disorders and sleep loss did not feature prominently
in this strategy, despite their high prevalence and effect on drowsiness and crashes....
Study objectives:
Drowsiness leads to 20% of fatal road crashes, while inability to assess drowsiness has hampered drowsiness interventions. This study examined the accuracy of eye-blink parameters for detecting drowsiness related driving impairment in real time.
Methods:
Twelve participants undertook two sessions of 2-hour track-driving in an i...
Context:
Studies suggest that female reproductive hormones are under circadian regulation, although methodologic differences have led to inconsistent findings.
Objective:
To determine whether circulating levels of reproductive hormones exhibit circadian rhythms.
Design:
Blood samples were collected across ∼90 consecutive hours, including 2 bas...
Practical alternatives to gold-standard measures of circadian timing in shift workers are needed. We assessed the feasibility of applying a limit-cycle oscillator model of the human circadian pacemaker to estimate circadian phase in 25 nursing and medical staff in a field setting during a transition from day/evening shifts (diurnal schedule) to 3–5...
A neural network model was previously developed to predict melatonin rhythms accurately from blue light and skin temperature recordings in individuals on a fixed sleep schedule. This study aimed to test the generalizability of the model to other sleep schedules, including rotating shift work. Ambulatory wrist blue light irradiance and skin temperat...
Objective/background:
In the months after childbirth, women are vulnerable to sleep disturbances and sleep-related deficits in functioning, such as fatigue, daytime sleepiness, and attentional lapses. Currently there is limited evidence that these deficits are modifiable. Using both self-report and objective measures, this study examined changes i...
This study aimed to evaluate the association between shift work disorder and mental health in hospital‐based nurses. Staff completed an online survey comprising demographic questions, the Shift Work Disorder Questionnaire, Patient Health‐9 and the General Anxiety Disorder‐7 scale. Sick leave data were collected from archival records from the Human...
Significance
Electric lighting has fundamentally altered how the human circadian clock synchronizes to the day/night cycle. Exposure to light after dusk is pervasive in the modern world. We examined group-level sensitivity of the circadian system to evening light and the degree to which sensitivity varies between individuals. We found that, on aver...
This study investigated whether sleep disorder risk and mental health outcomes in firefighters were associated with burnout, particularly emotional exhaustion, and examined the mediating role of sleep at work in these relationships. A secondary aim was to investigate associations between habitual sleep characteristics and burnout. North American fi...
Melatonin and melatonin agonists offer novel treatments for sleep and mood disorders, particularly where circadian misalignment is also present. The therapies offer both phase-shifting and sleep-promoting effects and have shown potential to treat advanced and delayed sleep-wake phase disorder, non-24-h sleep-wake cycle, jetlag, shift work disorder,...
The PERIOD2 (PER2) gene is a core molecular component of the circadian clock and plays an important role in the generation and maintenance of daily rhythms. Rs35333999, a missense variant of PER2 common in European populations, has been shown to associate with later chronotype. Chronotype relates to the timing of biological and behavioral activitie...