EEG Microstates Indicate Heightened Somatic Awareness in Insomnia: Toward Objective Assessment of Subjective Mental Content

People with Insomnia Disorder (ID) not only experience abundant nocturnal mentation, but also report altered spontaneous mental content during daytime wakefulness, such as an increase in bodily experiences (heightened somatic awareness). Previous studies have shown that resting-state EEG can be temporally partitioned into quasi-stable microstates, and that these microstates form a small number of canonical classes that are consistent across people. Furthermore, the microstate classes have been associated with individual differences in resting mental content including somatic awareness. To address the hypothesis that altered resting mental content in ID would be reflected in an altered representation of the corresponding EEG microstates, we analyzed resting-state high-density EEG of 32 people with ID and 32 age- and sex-matched controls assessed during 5-min eyes-closed wakefulness. Using data-driven topographical k-means clustering, we found that 5 microstate classes optimally explained the EEG scalp voltage map sequences across participants. For each microstate class, 3 dynamic features were obtained: mean duration, frequency of occurrence, and proportional coverage time. People with ID had a shorter mean duration of class C microstates, and more frequent occurrence of class D microstates. The finding is consistent with previously established associations of these microstate properties with somatic awareness, and increased somatic awareness in ID. EEG microstate assessment could provide objective markers of subjective experience dimensions in studies on consciousness during the transition between wake and sleep, when self-report is not possible because it would interfere with the very process under study. Addressing somatic awareness may benefit psychotherapeutic treatment of insomnia

Genome-wide association analysis of insomnia complaints identifies risk genes and genetic overlap with psychiatric and metabolic traits.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked FilesPersistent insomnia is among the most frequent complaints in general practice. To identify genetic factors for insomnia complaints, we performed a genome-wide association study (GWAS) and a genome-wide gene-based association study (GWGAS) in 113,006 individuals. We identify three loci and seven genes associated with insomnia complaints, with the associations for one locus and five genes supported by joint analysis with an independent sample (n = 7,565). Our top association (MEIS1, P < 5 × 10-8) has previously been implicated in restless legs syndrome (RLS). Additional analyses favor the hypothesis that MEIS1 exhibits pleiotropy for insomnia and RLS and show that the observed association with insomnia complaints cannot be explained only by the presence of an RLS subgroup within the cases. Sex-specific analyses suggest that there are different genetic architectures between the sexes in addition to shared genetic factors. We show substantial positive genetic correlation of insomnia complaints with internalizing personality traits and metabolic traits and negative correlation with subjective well-being and educational attainment. These findings provide new insight into the genetic architecture of insomnia.Netherlands Organization for Scientific Research NWO Brain & Cognition 433-09-228 European Research Council ERC-ADG-2014-671084 INSOMNIA Netherlands Scientific Organization (NWO) VU University (Amsterdam, the Netherlands) Dutch Brain Foundation Helmholtz Zentrum Munchen - German Federal Ministry of Education and Research state of Bavaria German Migraine & Headache Society (DMKG) Almirall AstraZeneca Berlin Chemie Boehringer Boots Health Care GlaxoSmithKline Janssen Cilag McNeil Pharma MSD Sharp Dohme Pfizer Institute of Epidemiology and Social Medicine at the University of Munster German Ministry of Education and Research (BMBF) German Restless Legs Patient Organisation (RLS Deutsche Restless Legs Vereinigung) Swiss RLS Patient Association (Schweizerische Restless Legs Selbsthilfegruppe

Sleep, vigilance, and thermosensitivity

The regulation of sleep and wakefulness is well modeled with two underlying processes: a circadian and a homeostatic one. So far, the parameters and mechanisms of additional sleep-permissive and wake-promoting conditions have been largely overlooked. The present overview focuses on one of these conditions: the effect of skin temperature on the onset and maintenance of sleep, and alertness. Skin temperature is quite well suited to provide the brain with information on sleep-permissive and wake-promoting conditions because it changes with most if not all of them. Skin temperature changes with environmental heat and cold, but also with posture, environmental light, danger, nutritional status, pain, and stress. Its effect on the brain may thus moderate the efficacy by which the clock and homeostat manage to initiate or maintain sleep or wakefulness. The review provides a brief overview of the neuroanatomical pathways and physiological mechanisms by which skin temperature can affect the regulation of sleep and vigilance. In addition, current pitfalls and possibilities of practical applications for sleep enhancement are discussed, including the recent finding of impaired thermal comfort perception in insomniacs

Skin temperature, sleep, and vigilance

A large number of studies have shown a close association between the 24-hour rhythms in core body temperature and sleep propensity. More recently, studies have have begun to elucidate an intriguing association of sleep with skin temperature as well. The present chapter addresses the association of sleep and alertness with skin temperature. It discusses whether the association could reflect common underlying drivers of both sleep propensity and skin vasodilation; whether it could reflect efferents of sleep-regulating brain circuits to thermoregulatory circuits; and whether skin temperature could provide afferent input to sleep-regulating brain circuits. Sleep regulation and concomitant changes in skin temperature are systematically discussed and three parallel factors suggested: a circadian clock mechanism, a homeostatic hourglass mechanism, and a third set of sleep-permissive and wake-promoting factors that gate the effectiveness of signals from the clock and hourglass in the actual induction of sleep or maintenance of alert wakefulness. The chapter moreover discusses how the association between skin temperature and arousal can change with sleep deprivation and insomnia. Finally it addresses whether the promising laboratory findings on the effects of skin temperature manipulations on vigilance can be applied to improve sleep in everyday life

EEG Microstates Indicate Heightened Somatic Awareness in Insomnia: Toward Objective Assessment of Subjective Mental Content

People with Insomnia Disorder (ID) not only experience abundant nocturnal mentation, but also report altered spontaneous mental content during daytime wakefulness, such as an increase in bodily experiences (heightened somatic awareness). Previous studies have shown that resting-state EEG can be temporally partitioned into quasi-stable microstates, and that these microstates form a small number of canonical classes that are consistent across people. Furthermore, the microstate classes have been associated with individual differences in resting mental content including somatic awareness. To address the hypothesis that altered resting mental content in ID would be reflected in an altered representation of the corresponding EEG microstates, we analyzed resting-state high-density EEG of 32 people with ID and 32 age- and sex-matched controls assessed during 5-min eyes-closed wakefulness. Using data-driven topographical k-means clustering, we found that 5 microstate classes optimally explained the EEG scalp voltage map sequences across participants. For each microstate class, 3 dynamic features were obtained: mean duration, frequency of occurrence, and proportional coverage time. People with ID had a shorter mean duration of class C microstates, and more frequent occurrence of class D microstates. The finding is consistent with previously established associations of these microstate properties with somatic awareness, and increased somatic awareness in ID. EEG microstate assessment could provide objective markers of subjective experience dimensions in studies on consciousness during the transition between wake and sleep, when self-report is not possible because it would interfere with the very process under study. Addressing somatic awareness may benefit psychotherapeutic treatment of insomnia

Bright environmental light ameliorates deficient subjective 'liking' in insomnia:an experience sampling study

Study Objectives: Altered comfort sensing and reduced gray matter volume in the orbitofrontal cortex of the brain in people suffering from Insomnia Disorder (ID) suggest compromised processes of motivation and hedonia. The Experience Sampling (ES) method was used to evaluate whether, in naturalistic conditions, people with ID differ from those without sleep complaints with respect to subjective wanting and liking, two major dimensions of the reward system. Since light affects brain circuits involved in affect and reward, ES was combined with ambulatory monitoring of light intensity fluctuations to evaluate their effect on subjective wanting and liking. Methods: Participants with ID (n=17, 12 females, 56.8 ± 6.5 mean ± standard deviation years of age) and matched controls without sleep complaints (n=18, 12 females, 57.0 ± 8.6 years of age) were probed by a smartphone alarm to log their subjective wanting, liking and mood nine times a day for seven days. Using an ambulatory light recorder, light intensity exposure was sampled simultaneously and averaged over the intervals between subsequent ES alarms. Mixed effect models were used to evaluate how ID and varying light intensity affected subjective assessments. Results: The results indicated significantly lower subjective Liking and Wanting in people suffering from ID, particularly at low environmental light intensity. Conclusions: Wanting and liking, rather than more commonly used mood adjectives, showed an increased sensitivity to detect deficient hedonic and reward processing in insomnia during everyday life. Deficient liking may in part be rescued by exposure to bright environmental light

Objectively measured sleep and body mass index: a prospective bidirectional study in middle-aged and older adults.

BACKGROUND In recent years, short sleep has been increasingly recognized as a risk factor for obesity. However, current evidence has so far been limited to cross-sectional studies or longitudinal studies using self-reported sleep. Therefore, we explored the directionality of the association between objectively measured sleep and body mass index (BMI). METHODS The study consists of 1031 participants from the general population (52% women, 45-91 years at baseline). Sleep, BMI and waist circumference (WC) were measured twice across a follow-up of six years. BMI and WC were measured at the research center. Total sleep time (TST, hrs), sleep onset latency (SOL, min), sleep efficiency (SE, %) and wake after sleep onset (WASO, min) were estimated by a wrist-worn actigraph. In addition, cross-sectional and longitudinal associations in both directions were explored. RESULTS An hour shorter TST was cross-sectionally associated with approximately 0.5 kg/m higher BMI. Longitudinally, longer TST and higher SE were associated with lower BMI (β = -0.75, 95% CI: -1.08, -0.42; β = -0.04, 95% CI: -0.08, -0.01). Conversely, one kg/m higher BMI was prospectively associated with 0.02 h shorter TST (95% CI: -0.03, -0.01), and this association was more pronounced over time. Results from analyses with WC were in line with those of BMI. CONCLUSIONS This is the first study to explore bidirectionality in the association between objectively measured sleep and BMI in a large population of middle-aged and older adults. Indices of poor sleep were associated with higher and less stable BMI across time. Conversely, a high BMI was associated with a decrease in sleep duration. This confirms that the relation between sleep and body size is bidirectional, and changes in either sleep or BMI are likely to co-occur with changes in health through multiple pathways

Environmental light and time of day modulate subjective liking and wanting

Several studies demonstrated effects of light on affect via projections from the retina of the eye to the circadian clock or via projections to areas involved in mood and reward. Few field studies investigated how naturally fluctuating light levels affect positive and negative mood in everyday life, but none addressed two key components of the reward system: wanting and liking. To elucidate diurnal profiles and immediate effects of dynamically changing light intensity in everyday life, subjective wanting and liking were assessed using experience sampling, while continuously monitoring environmental illuminance. Using a smartphone and light sensors, healthy volunteers (n = 27, 14 females, 23.7 ± 3.8 [M ± SD] years of age) were probed for 1 week, 9 times a day, to rate positive and negative mood, and 6 novel dedicated questions each on subjective liking and wanting. The multiband light spectrum was continuously recorded from sensors worn on the chest and intensities were averaged over the intervals between subsequent probes. Mixed effect models were used to evaluate how time of day and light intensity modulated subjective ratings. A total of 1,102 valid observations indicated that liking and wanting peaked around 6 p.m. and increased, respectively, by 13 ± 4% and 11 ± 4% across an individual's range of experienced light intensities. More traditional mood questions were less sensitive to modulation by light intensity. Combined experience sampling and environmental monitoring opens up the possibility for field studies on light in disorders in which the reward system is highly relevant, like addiction, depression and insomnia. (PsycINFO Database Recor

Optimizing actigraphic estimates of polysomnographic sleep features in insomnia disorder

© Sleep Research Society 2020. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail [email protected]. STUDY OBJECTIVES: Actigraphy is a useful tool for estimating sleep, but less accurately distinguishes sleep and wakefulness in patients with insomnia disorder (ID) than in good sleepers. Specific algorithm parameter settings have been suggested to improve the accuracy of actigraphic estimates of sleep onset or nocturnal sleep and wakefulness in ID. However, a direct comparison of how different algorithm parameter settings affect actigraphic estimates of sleep features has been lacking. This study aimed to define the optimal algorithm parameter settings for actigraphic estimates of polysomnographic sleep features in people suffering from ID and matched good sleepers. METHODS: We simultaneously recorded actigraphy and polysomnography without sleep diaries during 210 laboratory nights of people with ID (n = 58) and matched controls (CTRL) without sleep complaints (n = 56). We analyzed cross-validation errors using 150 algorithm parameter configurations and Bland-Altman plots of sleep features using the optimal settings. RESULTS: Optimal sleep onset latency and total sleep time (TST) errors were lower in CTRL (8.9 ± 2.1 and 16.5 ± 2.1 min, respectively) than in ID (11.7 ± 0.8 and 29.1 ± 3.4 min). The sleep-wake algorithm, a period duration of 5 min, and a wake sensitivity threshold of 40 achieved optimal results in ID and near-optimal results in CTRL. Bland-Altman plots were nearly identical for ID and controls for all common all-night sleep features except for TST. CONCLUSION: This systematic evaluation shows that actigraphic sleep feature estimation can be improved by using uncommon parameter settings. One specific parameter setting provides (near-)optimal estimation of sleep onset and nocturnal sleep across ID and controls

The experienced temperature sensitivity and regulation survey

Individuals differ in thermosensitivity, thermoregulation, and zones of thermoneutrality and thermal comfort. Whereas temperature sensing and -effectuating processes occur in part unconsciously and autonomic, awareness of temperature and thermal preferences can affect thermoregulatory behavior as well. Quantification of trait-like individual differences of thermal preferences and experienced temperature sensitivity and regulation is therefore relevant to obtain a complete understanding of human thermophysiology. Whereas several scales have been developed to assess instantaneous appreciation of heat and cold exposure, a comprehensive scale dedicated to assess subjectively experienced autonomic or behavioral thermoregulatory activity has been lacking so far. We constructed a survey that specifically approaches these domains from a trait-like perspective, sampled 240 volunteers across a wide age range, and analyzed the emergent component structure. Participants were asked to report their thermal experiences, captured in 102 questions, on a 7-point bi-directional Likert scale. In a second set of 32 questions, participants were asked to indicate the relative strength of experiences across different body locations. Principal component analyses extracted 21 meaningful dimensions, which were sensitive to sex-differences and age-related changes. The questions were also assessed in a matched sample of 240 people with probable insomnia to evaluate the sensitivity of these dimensions to detect group differences in a case-control design. The dimensions showed marked mean differences between cases and controls. The survey thus has discriminatory value. It can freely be used by anyone interested in studying individual or group differences in thermosensitivity and thermoregulation