Katharina Wulff

Umeå University | UMU

Background Light exposure significantly impacts human health, regulating our circadian clock, sleep–wake cycle and other physiological processes. With the emergence of wearable light loggers and dosimeters, research on real-world light exposure effects is growing. There is a critical need to standardize data collection and documentation across stud...

Objectives and study: Obesity in young children is increasing and one major contributing factor is likely decreased physical activity. Studies on young 3-year-old children´s physical activity are scare and limited by valid measures of physical activity. Hence, this study aimed at (i) calibrating activity counts of motor behaviour measured simultane...

Light exposure fundamentally influences human physiology and behavior, with light being the most important zeitgeber of the circadian system. Throughout the day, people are exposed to various scenes differing in light level, spectral composition and spatio-temporal properties. Personalized light exposure can be measured through wearable light logge...

Introduction Behaviour-based physical intensities have not undergone rigorous calibration in long-term recordings of 3-year-old children’s sleep/activity patterns. This study aimed at (i) calibrating activity counts of motor behaviour measured simultaneously with MotionWatch 8 (MW8) and ActiGraph (GT3X) in 3-year-old children, (ii) documenting move...

This article introduces a comprehensive metadata descriptor aimed at capturing crucial metadata information within personalized light exposure datasets. This metadata descriptor fills a critical gap in the field of personalized light exposure research by promoting standardized documentation of light exposure metadata. Light exposure profoundly impa...

Background: Anaemia in pregnancy is a global health problem with associated maternal and neonatal morbidity and mortality. We aimed to investigate the association between maternal haemoglobin concentrations during pregnancy and the risk of adverse maternal and neonatal outcomes. Methods: In this prospective, observational, multinational, INTERBI...

This poster describes a new method to induce antidepressant response in patients that have driftet to later in their depressive episode by inducing a sleep phase advance by use of the Circadian Reinforcement Therapy augmenting zeitgeber signals through daylight, meals, exercise and social activity.

Light exposure fundamentally influences human physiology and behavior, with light being the most important zeitgeber of the circadian system. Throughout the day, people are exposed to a variety of different scenes differing in light level, spectral composition and spatio-temporal properties. Personalized light exposure can be measured through weara...

Study objectives Environmental cues influence circadian rhythm timing and neurochemicals involved in the regulation of affective behaviour. 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...

Sleep plays a key role in supporting brain function and resilience to brain decline. It is well known that sleep changes substantially with aging and that aging is associated with deterioration of brain structure. In this study, we sought to characterize the relationship between slow wave slope (SWslope)—a key marker of sleep architecture and an in...

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 suff...

Psychotic experiences (PE) are associated with poorer functioning, higher distress and the onset of serious mental illness. Environmental exposures (e.g. childhood abuse) are associated with the development of PE. However, which specific exposures convey risk for each type or dimension of PE has rarely been explored. The Oxford Wellbeing Life and S...

Primary insomnia is often considered a disorder of 24‐hr hyperarousal. Numerous attempts have been made to investigate nocturnal heart rate (HR) and its variability (HRV) as potential pathophysiological hallmarks of altered arousal levels in insomnia, with mixed results. We have aimed to overcome some of the pitfalls of previous studies by using a...

Sleep and memory processing impairments range from mild to severe in the psychosis spectrum. Relationships between memory processing and sleep characteristics have been described for schizophrenia, including unaffected first-degree relatives, but they are less clear across other high-risk groups within the psychosis spectrum. In this study, we inve...

Objectives To describe the construction of the international INTERGROWTH-21st Neurodevelopment Assessment (INTER-NDA) standards for child development at 2 years by reporting the cognitive, language, motor and behaviour outcomes in optimally healthy and nourished children in the INTERGROWTH-21st Project. Design Population-based cohort study, the IN...

Daylight stems solely from direct, scattered and reflected sunlight, and undergoes dynamic changes in irradiance and spectral power composition due to latitude, time of day, time of year and the nature of the physical environment (reflections, buildings and vegetation). Humans and their ancestors evolved under these natural day/night cycles over mi...

Purpose: Diabetic retinopathy (DR) is associated with retinal neuronal and vascular damage. DR has previously been shown to affect the photosensitive retinal ganglion cells (pRGCs). PRGCs are essential for the entrainment of circadian rhythms; thus, DR progression could lead to worsening sleep quality and mood. We investigate the relationship betw...

Since ancient times it is known that melancholia and sleep disturbances co-occur. The introduction of polysomnography into psychiatric research confirmed a disturbance of sleep continuity in patients with depression, revealing not only a decrease in Slow Wave Sleep, but also a disinhibition of REM (rapid eye movement) sleep, demonstrated as a short...

Manual scoring of polysomnography data is labor-intensive and time-consuming, and most existing software does not account for subjective differences and user variability. Therefore, we evaluated a supervised machine learning algorithm, SomnivoreTM, for automated wake–sleep stage classification. We designed an algorithm that extracts features from v...

Sleep enhances the consolidation of memory; however, this property of sleep may be detrimental in situations where memories of an event can lead to psychopathology, such as following a traumatic event. Intrusive memories of trauma are emotional memories that spring to mind involuntarily and are a core feature of post-traumatic stress disorder. Tota...

Background: INTERBIO-21 st is Phase II of the INTERGROWTH-21 st Project, the population-based, research initiative involving nearly 70,000 mothers and babies worldwide coordinated by Oxford University and performed by a multidisciplinary network of more than 400 healthcare professionals and scientists from 35 institutions in 21 countries worldwide....

Background: INTERBIO-21 st is Phase II of the INTERGROWTH-21 st Project, the population-based, research initiative involving nearly 70,000 mothers and babies worldwide coordinated by Oxford University and performed by a multidisciplinary network of more than 400 healthcare professionals and scientists from 35 institutions in 21 countries worldwide....

Introduction: Mood disorders are among the most prevalent and serious mental disorders and rank high among to the leading global burdens of disease. The developmental psychopathology framework can offer a life course perspective on them thus providing a basis for early prevention and intervention. Sleep disturbances, are considered risk factors fo...

In humans and most other species, changes in the intensity and duration of light provide a critical set of signals for the synchronisation of the circadian system to the astronomical day. The timing of activity within the 24 h day defines an individual’s chronotype, i.e. morning, intermediate or evening type. The aim of this study was to investigat...

Insight problem solving is thought to underpin creative thought as it incorporates both divergent (generating multiple ideas and solutions) and convergent (arriving at the optimal solution) thinking approaches. The current literature on schizotypy and creativity is mixed and requires clarification. An alternate approach was employed by designing an...

Introduction Psychotic experiences (PE) are associated with poorer functioning, higher distress, poor sleep, and the onset of serious mental illness. Numerous studies have examined the genetic liability of dimensions in PE - yet relatively little is known about the specificity of environmental and sleep exposures in the prediction of PE dimensions....

Disrupted sleep is a transdiagnostic factor characterising a multitude of psychiatric conditions. Although this is well-recognised, the cause of poor sleep across conditions is unclear. One possibility is that poor sleep is driven by traits which also co-occur with multiple conditions. Previous research suggests that alexithymia (an inability to id...

Purpose of review: The review is designed to give an overview of the latest developments in research exploring the relationship between sleep and psychosis, with particular attention paid to the evidence for a causal relationship between the two. Recent findings: The most interesting avenues currently in pursuit are focused upon sleep spindle de...

Investigations into schizophrenia have revealed a high incidence of comorbidity with disturbed sleep and circadian timing. Acknowledging this comorbidity on a dimensional level, we tested prospectively whether subclinical psychotic symptoms are more prevalent in individuals with insomnia. An insomnia group (n = 21) and controls (n = 22) were recrui...

Objective: Age-related cognitive impairment and the prevalence of neurodegenerative disease contribute to decreasing quality of life in affected individuals and their families as well as demand considerable societal responsibility. Sleep supports overall brain activity and contributes to both physical and mental health. As a result, sleep is an at...

Light exerts influences on many physiological and behavioural functions in humans. These functions can be described as image-forming (IF) and non-image forming (NIF) visual processes, both originating in the retina of the eye. Image-forming refers to vision; the process of detecting and distinguishing shapes and colour of objects. Non-image forming...

Introduction Insomnia is the most prevalent sleep disorder and one of the most common complaints in primary care. Despite this, the pathophysiology underpinning insomnia complaints are still poorly understood. There have been numerous attempts to investigate the possibility of nocturnal heart rate (HR) and its variability as physiological hallmarks...

Appendix S1 Members of the International Fetal and Newborn Growth Consortium for the 21st Century (INTERGROWTH‐21st and INTERBIO‐21st) and its Committees

Figure S1 Relationship between fetal weight and abdominal circumference in the final model, plotted for a fixed head circumference of 26 cm.

Figure S2 Relationship between fetal weight and head circumference in the final model, plotted for a fixed abdominal circumference of 23 cm.

Figure S4 Gestational age‐specific centiles for estimated fetal weight (blue) and birth weight (red). 3rd, 10th, 50th, 90th and 97th centiles are shown.

Table S1 Estimated fetal weight per completed week of gestation at 3rd, 10th, 50th, 90th and 97th centiles

Figure S3 Bias in estimation of fetal weight as a function of time to birth, showing mean percent prediction error and 95% CI according to time between last ultrasound scan and birth.

A–B pair performance in the 1-week test in the sleep and wake conditions of the word-pair associates task, in people with TEA-associated ALF and control participants. Error bars represent standard errors of the mean.

The benefit of post-learning sleep for memory retention over twelve hours (top charts) and one week (bottom charts) plotted against the percentage of total sleep time spent in REM sleep (left charts) and NREM2 sleep (right charts) during the sleep condition night. The lines of best fit and R2 values are displayed for the significant correlations. T...

The benefit of post-learning sleep for memory retention over twelve hours (top charts) and one week (bottom charts) plotted against the spindle incidence in SWS (the number of spindles in SWS/the total number of artefact free SWS min) during the sleep condition night. There were no significant results.

TEA patient information, adapted from Atherton et al. (2014). AEDs = Anti-Epileptic Drugs that the patients were taking when they took part in the sleep experiment, LEV = Levetiracetam, CBZ = Carbamazepine, LTG = Lamotrigine, SVP = Sodium Valproate.

A–B pair performance in the final training test, the 30-min test and the 12-h test in the sleep and wake conditions of the word-pair associates task, in people with TEA-associated ALF and control participants, taken from Atherton et al. (2014). Error bars represent standard errors of the mean.

The benefit of post-learning sleep for memory retention over twelve hours (top charts) and one week (bottom charts) plotted against the spindle incidence in NREM2 (the number of spindles in NREM2/the total number of artefact free NREM2 min) during the sleep condition night. There were no significant results.

Participant information, adapted from Atherton et al. (2014). Means with SEMs in brackets. Patients and controls did not significantly differ in terms of age, years of full-time education or test scores (ps > .05). aNART (Nelson, 1982; Nelson & Willison, 1991); bWAIS = Wechsler Abbreviated Intelligence Scale (Wechsler, 1955); cWASI = Wechsler Abbre...

Performance on the word-pair associates task, adapted from Atherton et al. (2014). Means with SEMs in brackets. The three A–B word-pair tests that are plotted in Fig. 2a are in boldface.

We investigated whether the benefit of slow wave sleep (SWS) for memory consolidation typically observed in healthy individuals is disrupted in people with accelerated long-term forgetting (ALF) due to epilepsy. SWS is thought to play an active role in declarative memory in healthy individuals and, furthermore, electrographic epileptiform activity...

Poor sleep is an increasingly recognised problem with chronic pain and further increases the effect on daily function. To identify the relationship between chronic pain, opioid analgesia and sleep quality, this study investigated activity and sleep patterns in patients taking opioid and non-opioid analgesia for chronic back pain. Thirty-one partici...

Background: Quetiapine is an atypical antipsychotic that can stabilise mood from any index episode of bipolar disorder. This study investigated the effects of seven-day quetiapine administration on sleep, circadian rhythms and emotional processing in healthy volunteers. Methods: Twenty healthy volunteers received 150 mg quetiapine XL for seven n...

Methods: It was a cross-sectional study assessing AEDs gathered from public, private and illegal circuits. Analyses were carried out in France following Pharmacopeia recommendations. Several tests (active ingredients assay, related substances screening, mass uniformity , dissolution, disintegration and friability) were conducted to assess the quali...

Study objectives: To group participants according to markers of risk for severe mental illness based on subsyndromal symptoms reported in early adulthood and evaluate attributes of sleep across these risk categories. Methods: An online survey of sleep and psychiatric symptomatology (The Oxford Sleep Survey) was administered to students at one Un...

A number of studies have established an association between antenatal maternal depression and infant sleep. One key question is whether all infants are equally susceptible to environmental influences, including the intrauterine environment. Reactive temperament has been examined as a plasticity factor, with accumulating evidence suggesting that inf...

To examine the effect of sleep deprivation compared to sleep, immediately after experimental trauma stimuli on the development of intrusive memories to that trauma stimuli. Participants were exposed to a film with traumatic content (trauma film). The immediate response to the trauma film was assessed, followed by either total sleep deprivation (sle...

It is often suggested that sleep-dependent consolidation of motor learning is impaired in older adults. The current study challenges this view and suggests that the degree of motor consolidation seen with sleep in older age groups depends on the kinematic demands of the task. We show that, when tested with a classic sequence learning task, requirin...

Background The International Fetal and Newborn Growth Consortium for the 21st Century (INTERGROWTH-21st) Project is a population-based, longitudinal study describing early growth and development in an optimally healthy cohort of 4607 mothers and newborns. At 24 months, children are assessed for neurodevelopmental outcomes with the INTERGROWTH-21st...

Purpose: Although visual impairment is a well-recognized consequence of cataract development, little is known about the ability of the melanopsin-based photosensitive retinal ganglion cells (pRGCs) to regulate sleep-wake timing in the presence of cataract. In this study, we replaced a cataractous natural crystalline lens with two different types o...

This study assessed daily rest-activity patterns in euthymic, medication-naïve bipolar phenotype individuals. The Mood Disorder Questionnaire was used to identify 19 bipolar phenotype individuals and 21 controls. Participants wore an Actiwatch-L for 2 weeks to assess their sleep behaviour and circadian rest-activity rhythmicity. Bipolar phenotype i...

Sleep and wake represent two profoundly different states of physiology that arise within the brain from a complex interaction between multiple neural circuits and neurotransmitter systems. These neural networks are, in turn, adjusted by three key drivers that collectively determine the duration, quality, and efficiency of sleep. Two of these driver...

Objective: A previous study, based upon direct nursing observations, showed almost half of a cohort of inpatients with severe, enduring OCD also suffered from delayed sleep phase shift. Males, younger patients and those with more severe symptoms were most likely to be affected. However, the ward environment may have had a direct effect on sleeping...

Sleep and circadian rhythm disruption (SCRD) and schizophrenia are often co-morbid. Here, we propose that the co-morbidity of these disorders stems from the involvement of common brain mechanisms. We summarise recent clinical evidence that supports this hypothesis, including the observation that the treatment of SCRD leads to improvements in both t...

Sleep and circadian rhythm disruption has been widely observed in neuropsychiatric disorders including schizophrenia [1] and often precedes related symptoms [2]. However, mechanistic basis for this association remains unknown. Therefore, we investigated the circadian phenotype of blind-drunk (Bdr), a mouse model of synaptosomal-associated protein (...

Sleep disturbances comparable with insomnia occur in up to 80% of people with schizophrenia, but very little is known about the contribution of circadian coordination to these prevalent disruptions. A systematic exploration of circadian time patterns in individuals with schi