The clock as a focus of selective attention in those with primary insomnia: an experimental study using a modified Posner paradigm

Sleep-related attentional bias in insomnia: The mediating role of arousal

BACKGROUND AND OBJECTIVES

Characterize the nature of attentional biases toward nocturnal and diurnal sleep-related stimuli in individuals with insomnia disorder. We investigated the contributing role of sleep-related attentional biases in insomnia severity and whether their effects on insomnia severity were mediated by arousal and valence levels of the presented stimuli.

METHODS

Sixty-four individuals with insomnia disorder and 70 controls completed two Posner spatial cueing tasks including both nocturnal (alarm clocks) and diurnal (fatigue) pictorial stimuli associated with neutral cues. Arousal and valence of the sleep-related stimuli were assessed using a 5-point Likert type scale.

RESULTS

Attention biases characterized by difficulty disengaging from and increased avoidance for daytime fatigue, and by difficulty disengaging from alarm clocks were observed in individuals with insomnia disorder compared to controls. On the whole sample, difficulty to disengage from diurnal and nocturnal sleep-related stimuli were related mostly to higher arousal rating of sleep-related stimuli and insomnia severity. Higher arousal rating for sleep-related stimuli mediates the relationship between difficulty disengaging and insomnia severity.

LIMITATIONS

The cross-sectional nature of the study.

CONCLUSIONS

We provide first initial evidence for an attentional bias characterized by on one side, avoidance for diurnal sleep-related stimuli and on other side, disengagement for both diurnal and nocturnal sleep-related stimuli in patients with insomnia. Disengagement difficulties for both diurnal and nocturnal sleep-related stimuli indirectly affected insomnia severity through arousal elicited by these stimuli. It appears important to develop and apply attentional bias modification training therapeutic interventions that can effectively reduce sleep-related arousal and attentional biases.

Assessing the daily association of sleep hygiene behaviours with sleep: A between and within persons approach

Sleep hygiene behaviours are recommendations given to both clinical and non-clinical populations with a focus on modifying behaviours to maximise sleep outcomes. However, methodological issues present in sleep hygiene research make it difficult to conclusively determine the impact of each behaviour. This study aimed to address these issues by adopting a two-week, repeated measures design which incorporated objective sleep measures and used linear mixed effect modelling to assess the daily association of a wide range of sleep hygiene behaviours on sleep in a non-clinical, university sample. Between-persons effects revealed that bedtime and frequency of daytime napping, alcohol use, and social media use were negatively related to sleep duration while waketime and frequency of too much water consumption were positively related to sleep duration. Within-person effects revealed that later than usual bedtime, earlier than usual waketime, no sunlight exposure, poor ventilation, having an unpleasant conversation before bed were negatively associated with sleep duration whereas using alcohol to deliberately help full asleep was positively related to sleep duration. In contrast, disproportionately more behaviours were not significantly related to either sleep outcome, only some of which could be explained by individual differences, which suggests that more research is needed to determine the conditions under which these behaviours affect sleep, if at all.

Mechanisms of cognitive behavioural therapy for insomnia

Although much is known now about behavioural, cognitive and physiological consequences of insomnia, little is known about changes after cognitive behavioural therapy for insomnia on these particular factors. We here report baseline findings on each of these factors in insomnia, after which we address findings on their changes after cognitive behavioural therapy. Sleep restriction remains the strongest determinant of insomnia treatment success. Cognitive interventions addressing dysfunctional beliefs and attitudes about sleep, sleep-related selective attention, worry and rumination further drive effectiveness of cognitive behavioural therapy for insomnia. Future studies should focus on physiological changes after cognitive behavioural therapy for insomnia, such as changes in hyperarousal and brain activity, as literature on these changes is sparse. We introduce a detailed clinical research agenda on how to address this topic.

Covariance patterns between sleep health domains and distributed intrinsic functional connectivity

Sleep health is both conceptually and operationally a composite concept containing multiple domains of sleep. In line with this, high dependence and interaction across different domains of sleep health encourage a transition in sleep health research from categorical to dimensional approaches that integrate neuroscience and sleep health. Here, we seek to identify the covariance patterns between multiple sleep health domains and distributed intrinsic functional connectivity by applying a multivariate approach (partial least squares). This multivariate analysis reveals a composite sleep health dimension co-varying with connectivity patterns involving the attentional and thalamic networks and which appear relevant at the neuromolecular level. These findings are further replicated and generalized to several unseen independent datasets. Critically, the identified sleep-health related connectome shows diagnostic potential for insomnia disorder. These results together delineate a potential brain connectome biomarker for sleep health with high potential for clinical translation.

Sleep-related attentional and interpretive-bias in insomnia: A systematic review and meta-analysis

Cognitive models of insomnia highlight internal and external cognitive-biases for sleep-related "threat" in maintaining the disorder. This systematic review of the sleep-related attentional and interpretive-bias literature includes meta-analytic calculations of each construct. Searches identified N = 21 attentional-bias and N = 8 interpretive-bias studies meeting the inclusion/exclusion criteria. Seventeen attentional-bias studies compared normal-sleepers and poor-sleepers/insomnia patients. Using a random effects model, meta-analytic data based on standardized mean differences of attentional-bias studies determined the weighted pooled effect size to be moderate at 0.60 (95%CI:0.26-0.93). Likewise, seven of eight interpretive-bias studies involved group comparisons. Meta-analytic data determined the weighted pooled effect size as moderate at .44 (95%CI:0.19-0.69). Considering these outcomes, disorder congruent cognitive-biases appear to be a key feature of insomnia. Despite statistical support, absence of longitudinal data limits causal inference concerning the relative role cognitive-biases in the development and maintenance of insomnia. Methodological factors pertaining to task design, sample and stimuli are discussed in relation to outcome variation. Finally, we discuss the next steps in advancing the understanding of sleep-related biases in insomnia.

Attentional Bias for Sleep-Related Words as a Function of Severity of Insomnia Symptoms

Attentional bias to sleep-related information is thought to be a core feature for developing and/or maintaining insomnia. This study used a hallmark measure of attentional bias, the dot-probe task, to determine whether this bias toward sleep-related stimuli was a function of the severity of insomnia symptoms. A sample of 231 volunteers (175 females; mean age of 26.91 ± 8.05 years) participated in this online study, filling out the Insomnia Severity Index (ISI) and performing a visual dot-probe task. After categorizing individuals based on the ISI score into normal, subclinical, and moderate/severe sleep groups, we only found a marginally significant interaction between sleep groups and the type of stimuli on RTs, suggesting that subclinical and moderate/severe sleep groups reported slower RTs for sleep-related words than for neutral words. When we calculated the attentional bias score (ABS), we found that ABS significantly differed from zero in the moderate/severe sleep group only, suggesting a disengagement for sleep-related information as a function of the severity of insomnia symptoms. This finding seems to suggest that insomnia is related to greater difficulties in shifting away from sleep-related stimuli.

Association of perceptions of artificial light-at-night, light-emitting device usage and environmental noise appraisal with psychological distress, sleep quality and chronotype: A cross sectional study

Exposure to artificial light-at-night (ALAN) is increasing globally, and there are concerns around how ALAN may impact sleep, psychological and physical health. However, there is a lack of evidence in the literature on how individuals perceive ALAN relative to their sleeping environment and habits, and how such perceptions correspond to objectively assessed night-time illuminance at the level of the residence. This cross-sectional study examined how such perceptions associate with sleep quality, sleep timing, psychological distress and cognitive failures. Further we examined the association between illuminance levels calculated as the biologically-relevant melatonin-suppression index (MSI) and the self-report of perception of ALAN. Five hundred and fifty two adult participants completed a survey addressing perception of ALAN in sleep environment along with the Pittsburgh Sleep Quality Index, Munich Chronotype Questionnaire, Cognitive Failure Questionnaire and the General Health Questionnaire. We report that perception of external ALAN in the sleeping environment was associated with poorer sleep quality, more cognitive failures and greater psychological distress, when controlling for age, sex, house location and MSI. No associations were found between the perception of external ALAN and MSI scores, and MSI scores were not associated with scores on any of the self-report measures. Internal lighting passing into the sleeping environment was associated with poorer sleep quality but not with psychological wellbeing. Habitual use of light-emitting devices was associated with poorer psychological wellbeing but not with sleep quality and sleep timing. Perception of environmental noise annoyance at night was associated with higher psychological distress and poorer quality sleep, and the perception of noise annoyance was associated with perception of ALAN. These results may suggest heightened attentional bias towards ALAN associated with poor sleep quality and higher levels of psychological distress, and highlight the need for more granular approaches in the study of ALAN and sleep and psychological health in terms of levels individual ALAN exposure, and an interpretation that seeks to integrate biological and psychological perspectives.

Poor false sleep feedback does not affect pre-sleep cognitive arousal or subjective sleep continuity in healthy sleepers: a pilot study

Modern wearable devices calculate a numerical metric of sleep quality (sleep feedback), which are intended to allow users to monitor and, potentially, improve their sleep. This feedback may have a negative impact on pre-sleep cognitive arousal, and subjective sleep, even in healthy sleepers, but it is not known if this is the case. This pilot study examined the impact of poor false sleep feedback, upon pre-sleep arousal and subjective sleep continuity in healthy sleepers. A total of 54 healthy sleepers (Mage = 30.19 years; SDage = 12.94 years) were randomly allocated to receive good, or poor, false sleep feedback, in the form of a numerical sleep score. Participants were informed that this feedback was a true reflection of their habitual sleep. Pre-sleep cognitive and somatic arousal was measured at baseline, immediately after the presentation of the feedback, and one week afterwards. Subjective sleep continuity was measured using sleep diaries for one week before, and after, the presentation of the feedback. There were no significant differences between good and poor feedback groups in terms of pre-sleep cognitive arousal, or subjective sleep continuity, before or after the presentation of the sleep feedback. The presentation of false sleep feedback, irrespective of direction (good vs. poor) does not negatively affect pre-sleep cognitive arousal or subjective sleep continuity in healthy sleepers. Whilst the one-off presentation of sleep feedback does not negatively affect subjective sleep, the impact of more frequent sleep feedback on sleep should be examined.

Mindfulness-based Cognitive Therapy to Improve Sleep Quality in Older Adults with Insomnia

There is a high prevalence of insomnia in older adults, which has negative consequences for their well-being and quality of life. The recommendation for first-line treatments is to administer non-pharmacological interventions. The objective of this research was to verify the effectiveness of Mindfulness-Based Cognitive Therapy in older adults with subclinical and moderate insomnia, studying its impact on sleep quality. One hundred and six older adults participated and were assigned to the subclinical insomnia (n = 50) or moderate insomnia (n = 56) groups; subsequently, they were randomly assigned to the control and intervention groups. Subjects were evaluated at two times with the Insomnia Severity Index and the Pittsburgh Sleep Quality Index. Significant results were obtained on both scales, with a reduction in insomnia symptoms in the subclinical and moderate intervention groups. The administration of a treatment that combines mindfulness and cognitive therapy is effective for treating insomnia in older adults.

Objective Measures of Cognitive Performance in Sleep Disorder Research

Neurocognitive tests offer objective and reliable assessment of patients' status and progress. However, there is no consensus on how to use neurocognitive assessment in sleep disorder research. An effective use of neurocognitive assessment must be based on standardized practices and have a firm theoretic basis. The aim of this review is to offer an overview of how different tests have been used in the field, mapping each test onto a corresponding cognitive domain and propose how to move forward with a suggested cognitive battery of tests covering all major cognitive domains.

Hard to initiate sleep: a new paradigm for resting-state fMRI

A better understanding of the neural mechanism of sleep initiation is helpful for sleep health. Our current study aimed to develop a new paradigm that is suitable for using resting-state functional magnetic resonance imaging (rs-fMRI) to investigate the inability to initiate sleep. We recruited 28 subjects from nearby communities, in addition to traditionally resting-state eyes-closed condition (EC), they were further asked to try-to-sleep (TTS) in the MRI scanner. Independent component analysis (ICA) was used to extract the large-scale brain networks. No significant difference was found between EC and TTS in the amplitude of brain activity, nor the functional connectivity. However, under the condition of TTS, there was a significant negative correlation between functional connectivity and sleep quality. The results suggesting that the stronger the functional connectivity between the visual network and default mode network, the worse the sleep quality. The results of our research presented here suggested the increased integration among the visual thought-related networks of poor sleepers during sleep onset. More importantly, this study attempt to combine the sleep latency test with resting-state fMRI, and it may help us to investigate the neural mechanism of sleep initiation problem.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11571-020-09659-6.

Conceptual Framework for Insomnia: A Cognitive Model in Practice

Insomnia is a widespread neuropsychological sleep-related disorder known to result in various predicaments including cognitive impairments, emotional distress, negative thoughts, and perceived sleep insufficiency besides affecting the incidence and aggravation of other medical disorders. Despite the available insomnia-related theoretical cognitive models, clinical studies, and related guidelines, an evidence-based conceptual framework for a personalized approach to insomnia seems to be lacking. This study proposes a conceptual cognitive framework (CCF) providing insight into cognitive mechanisms involved in the predisposition, precipitation, and perpetuation of insomnia and consequent cognitive deficits. The current CCF for insomnia relies on evaluative conditional learning and appraisal which generates negative valence (emotional value) and arousal (cognitive value). Even with the limitations of this study, the suggested methodology is well-defined, reproducible, and accessible can help foster future high-quality clinical databases. During clinical insomnia but not the neutral one, negative mood (trait-anxiety) causes cognitive impairments only if mediating with a distorted perception of insomnia (Ind-1 = 0.161, 95% CI 0.040–0.311). Further real-life testing of the CCF is intended to formulate a meticulous, decision-supporting platform for clinical interventions. Furthermore, the suggested methodology is expected to offer a reliable platform for CCF-development in other cognitive impairments and support the causal clinical data models. It may also improve our knowledge of psychological disturbances and complex comorbidities to help design rehabilitation interventions and comprehensive frameworks in line with the “preventive medicine” policies.

Sleep-Related Cognitive Processes and the Incidence of Insomnia Over Time: Does Anxiety and Depression Impact the Relationship?

Aim: According to the Cognitive Model of Insomnia, engaging in sleep-related cognitive processes may lead to sleep problems over time. The aim was to examine associations between five sleep-related cognitive processes and the incidence of insomnia, and to investigate if baseline anxiety and depression influence the associations. Methods: Two thousand three hundred and thirty-three participants completed surveys on nighttime and daytime symptoms, depression, anxiety, and cognitive processes at baseline and 6 months after the first assessment. Only those without insomnia at baseline were studied. Participants were categorized as having or not having incident insomnia at the next time point. Baseline anxiety and depression were tested as moderators. Results: Three cognitive processes predicted incident insomnia later on. Specifically, more safety behaviors and somatic arousal at Time 1 increased the risk of developing insomnia. When investigating changes in the cognitive processes over time, reporting an increase of worry and safety behaviors also predicted incident insomnia. Depressive symptoms moderated the association between changes in worry and incident insomnia. Conclusion: These findings provide partial support for the hypothesis that cognitive processes are associated with incident insomnia. In particular, safety behaviors, somatic arousal, and worry increase the risk for incident insomnia. Preventative interventions and future research are discussed.

Misperception of sleep is associated with intrinsic motivation toward thinking about sleep

BACKGROUND AND OBJECTIVES

Misperception of sleep, the underestimation of total sleep time and overestimation of sleep onset latency (SOL) relative to objective measures, is often found in people with sleep disturbances. Theories of insomnia have proposed that perceived sleeplessness triggers excessive intention and effort to sleep, ironically disturbing the normal initiation of sleep. The current study tested this specific association between (mis)perception of sleep and intrinsic motivation to think about sleep.

METHODS

The sample (n = 74) covered students and community living in Munich and surrounds with ages between 18 and 30 years. We assessed the subjective and objective sleep of participants using a sleep diary and actigraphy. Participants also completed a decision-making task (the pay-per-view task), where they had to decide between thinking about sleep vs. eating. As these options were associated with a variable monetary reward, participants typically experienced a conflict between their preferred topic and the reward for their choice.

RESULTS

Multilevel logistic regression analyses showed that participants with greater SOL misperception (i.e., longer subjective relative to objective SOL) forgo a greater reward for the opportunity to think about sleep.

LIMITATIONS

The non-clinical nature of our sample may limit the implication of the findings for clinical levels of insomnia.

CONCLUSIONS

Results support the cognitive model of insomnia, suggesting that perception of sleeplessness is associated with higher intrinsic motivation to engage in sleep-related thinking.

Decreased regional brain activity in response to sleep-related sounds after cognitive behavioral therapy for psychophysiological insomnia

AIM

Patients with psychophysiological insomnia (PI) experience hyperarousal, especially as a reaction to sound stimuli. In the current study, we explored brain activity changes in response to sleep-related sounds (SS) in patients with insomnia after cognitive behavioral therapy for insomnia (CBT-I).

METHODS

In 14 drug-free PI patients, regional brain activity in response to SS, and to white noise sound (NS) as neutral stimuli, was investigated before and after individual CBT-I using functional magnetic resonance imaging. Blood oxygen level-dependent (BOLD) signals to SS and NS were compared before and after CBT-I. In addition, the association between clinical improvement after CBT-I and changes in brain activity in response to SS and NS was analyzed.

RESULTS

Compared with baseline, regional brain activity in response to SS after CBT-I decreased in the left middle temporal and left middle occipital gyrus. In regression analysis, a reduction in the Dysfunctional Beliefs and Attitudes about Sleep (DBAS) Scale score after CBT-I was associated with decrease in brain activity in response to SS in both thalami. However, brain activity in response to NS showed no BOLD signal changes and no association with DBAS change.

CONCLUSION

Cortical hyperactivity, which may cause hyperarousal in PI, was found to decrease after CBT-I. CBT-I targeting changes in beliefs and attitudes about sleep may induce its therapeutic effects by reducing thalamic brain activity in response to sleep-related stimuli.

Brain Reactivity and Selective Attention to Sleep-Related Words in Patients With Chronic Insomnia

OBJECTIVE/BACKGROUND

Sleep-related attentional bias has been suggested to represent an important factor for the maintenance of chronic insomnia. However, little is known about potentially underlying psychological mechanisms such as threat or craving. As these are associated with distinguishable brain activation patterns, we performed a functional neuroimaging study.

PARTICIPANTS/METHODS

Functional magnetic resonance imaging was used to investigate brain reactivity to sleep-related words in 20 patients with primary insomnia according to DSM-IV criteria and 35 good sleeper controls according to Research Diagnostic Criteria. In addition, an emotional Stroop task was performed in all participants outside the scanner to investigate sleep-related attentional bias.

RESULTS

Contrary to the hypotheses, patients with chronic insomnia did not differ from good sleeper controls in terms of threat- or craving-related brain reactivity to sleep-related words. In addition, the emotional Stroop task did not reveal any significant group difference in sleep-related attentional bias. Exploratory analyses did not show any significant correlations between brain reactivity/selective attention to sleep-related words and questionnaire scores/PSG parameters.

CONCLUSIONS

The results from the present study call into question that attentional bias to sleep-related stimuli is a core feature of chronic insomnia. Future studies may use pictorial stimuli and larger sample sizes for investigating sleep-related information processing in insomnia.

Pre-sleep arousal can be associated with efficient processing of sleep-related information

BACKGROUND AND OBJECTIVES

Cognitive bias to sleep-related information is thought to be a core feature of sleep disturbances. The bias may enhance pre-sleep arousal, such as excessive worry about sleeplessness, which prevents people from initiating normal sleep onset. The present study focused on (a) attention bias toward sleep-related stimuli and (b) difficulty in updating working memory for sleep-related stimuli as two possible mechanisms underlying pre-sleep cognitive arousal.

METHOD

Participants (n = 61, a community sample) completed a dot-probe task (with sleep-related and matched control word stimuli) and a 1-back and 2-back task (with sleep-related and non-sleep-related pictorial stimuli).

RESULTS

For the dot-probe task, the results showed no significant association between pre-sleep cognitive arousal and sleep-related attention bias. However, the results of the 2-back task suggest that pre-sleep arousal is associated with decreased interference by sleep-related stimuli in maintaining non-sleep-related information. That is, individuals with higher levels of pre-sleep arousal are more efficient at processing sleep-related materials.

LIMITATIONS

The non-clinical nature of the sample may limit the clinical implications of the findings.

CONCLUSIONS

Although the current results cannot be explained by the extant cognitive theories of insomnia, we offer an alternative explanation based on the idea of worry as mental habit: mental processes that occur frequently (e.g., repetitive thoughts about sleep) require less cognitive resource. Therefore, sleep-related information may be processed easily without consuming much cognitive effort.

Sleep-Related Attentional Bias for Faces Depicting Tiredness in Insomnia: Evidence From an Eye-Tracking Study

STUDY OBJECTIVES

To date, evidence of an attentional bias in insomnia has mostly been obtained through reaction time tasks, with a limited number of studies using eye tracking. Here, using an eye-tracking paradigm, this study sought to determine whether individuals with insomnia display an attentional bias for novel faces depicting tiredness.

METHODS

Individuals with insomnia (n = 20) and normal sleepers (n = 20) viewed a series of face pairs depicting neutral and tired expressions each for periods of 4000 milliseconds. Eye movements were recorded using eye tracking, and first fixation onset, first fixation duration, total fixation duration, and total gaze duration were examined for three interest regions (eyes, nose, mouth).

RESULTS

Significant group × face interactions for total fixation duration and total gaze duration indicated that, regardless of interest-region, participants with insomnia spent more time fixating on and observing tired faces relative to neutral faces when compared with normal sleepers. Additionally, significant group × face × interest-region interactions for total fixation duration and total gaze duration indicated that participants with insomnia spent more time observing the eye region of the tired faces than the eye region of the neutral faces when compared with normal sleepers.

CONCLUSIONS

Individuals with insomnia display an attentional bias toward tired faces, more specifically for the eye region compared to normal sleepers. These findings contribute to our understanding of face perception in insomnia and provide more objective support for cognitive models of insomnia, suggesting that individuals with insomnia selectively attend to faces for tiredness cues.

Sleep-related attentional bias for tired faces in insomnia: Evidence from a dot-probe paradigm

People with insomnia often display an attentional bias for sleep-specific stimuli. However, prior studies have mostly utilized sleep-related words and images, and research is yet to examine whether people with insomnia display an attentional bias for sleep-specific (i.e. tired appearing) facial stimuli. This study aimed to examine whether individuals with insomnia present an attentional bias for sleep-specific faces depicting tiredness compared to normal-sleepers. Additionally, we aimed to determine whether the presence of an attentional bias was characterized by vigilance or disengagement. Forty-one individuals who meet the DSM-5 criteria for Insomnia Disorder and 41 normal-sleepers completed a dot-probe task comprising of neutral and sleep-specific tired faces. The results demonstrated that vigilance and disengagement scores differed significantly between the insomnia and normal-sleeper groups. Specifically, individuals with insomnia displayed difficulty in both orienting to and disengaging attention from tired faces compared to normal-sleepers. Using tired facial stimuli, the current study provides novel evidence that insomnia is characterized by a sleep-related attentional bias. These outcomes support cognitive models of insomnia by suggesting that individuals with insomnia monitor tiredness in their social environment.

Exploration of changes in the brain response to sleep-related pictures after cognitive-behavioral therapy for psychophysiological insomnia

Psychophysiological insomnia (PI) includes arousal to sleep-related stimuli (SS), which can be treated by cognitive behavioral therapy for insomnia (CBT-I). The present study was an exploratory, prospective intervention study that aimed to explore brain response to visual SS in PI before and after CBT-I. Blood oxygen level dependent (BOLD) signal differences in response to SS and neutral stimuli (NS) were compared between 14 drug-free PI patients and 18 good sleepers (GS) using functional magnetic resonance imaging (fMRI). BOLD changes after CBT-I in patients were also examined. PI patients showed higher BOLD activation to SS in the precentral, prefrontal, fusiform, and posterior cingulate cortices before CBT-I. The increased responses to SS were reduced after CBT-I. The increased response to SS in the precentral cortex was associated with longer wake time after sleep onset (WASO), and its reduction after CBT-I was associated with improvements in WASO. Clinical improvements after CBT-I were correlated with BOLD reduction in the right insula and left paracentral cortex in response to SS. PI showed hyper-responses to SS in the precentral cortex, prefrontal cortex, and default mode network and these brain hyper-responses were normalized after CBT-I. CBT-I may exert its treatment effects on PI by reducing hyper-responses to SS in the precentral cortex and insula.

Attention to beds in natural scenes by observers with insomnia symptoms

Attention biases to sleep-related stimuli are held to play a key role in the development and maintenance of insomnia, but such biases have only been shown with controlled visual displays. This study investigated whether observers with insomnia symptoms allocate attention to sleep-related items in natural scenes, by recording eye movements during free-viewing of bedrooms. Participants with insomnia symptoms and normal sleepers were matched in their visual exploration of these scenes, and there was no evidence that the attention of those with insomnia symptoms was captured more quickly by sleep-related stimuli than that of normal sleepers. However, the insomnia group fixated bed regions on more trials and, once fixated on a bed, also remained there for longer. These findings indicate that sleep stimuli are particularly effective in retaining visual attention in complex natural scenes.

Sleep disparity, race/ethnicity, and socioeconomic position

Sleep represents a set of biological functions necessary for the maintenance of life. Performing these functions, though, requires that an individual engage in behaviors, which are affected by social and environmental factors. Race/ethnicity and socioeconomic position represent categories of factors that likely play a role in the experience of sleep in the community. Previous studies have suggested that racial/ethnic minorities and the socioeconomically disadvantaged may be more likely to experience sleep patterns that are associated with adverse health outcomes. It is possible that disparities in sleep represent a pathway by which larger disparities in health emerge. This review (1) contextualizes the concept of race/ethnicity in biomedical research, (2) summarizes previous studies that describe patterns of sleep attainment across race/ethnicity groups, (3) discusses several pathways by which race/ethnicity may be associated with sleep, (4) introduces the potential role of socioeconomic position in the patterning of sleep, and (5) proposes future research directions to address this issue.

Sleep-related attentional bias in insomnia: A state-of-the-science review

Prominent models of insomnia posit that sleep-related attentional bias plays an important role in the development and maintenance of insomnia. Here we conduct the first systematic review of the sleep-related attentional bias construct, indexed through reaction time-based experimental tasks. Literature search identified 13 studies that met pre-defined inclusion/exclusion criteria. Included studies involved between-group comparisons (poor sleepers versus controls), as well as sleep manipulations and correlational investigations with healthy sleepers. For studies involving comparisons between poor sleepers and healthy controls, effect size estimates were computed for task-relevant dependent variables. Six of the nine studies comparing poor sleepers and controls revealed statistically significant group differences in support of a differential sleep-related attentional bias (medium-to-large effect sizes), with flicker, dot-probe and Posner tasks being most sensitive to group effects. Due to the paucity of studies and variability in design and measurement, no conclusions could be reached regarding manipulation or induction of attentional bias in good sleepers. Results from the relatively small number of studies support the presence of sleep-related attentional bias in insomnia; however, its role in the development and/or maintenance of insomnia remains to be elucidated. We set out a research agenda aimed at advancing the understanding of sleep-related attention bias.

Are cognitive "insomnia" processes involved in the development and maintenance of delayed sleep wake phase disorder?

Although individuals with delayed sleep wake phase disorder (DSWPD) and chronic insomnia disorder (CID) share many of the same phenomenological experiences, theories relating to the development and maintenance of these disorders are distinct in focus. Unlike CID, theory relating to DSWPD is primarily physiologically based and assumes almost no cognitive pathway. However, recent research findings suggest that individuals with DSWPD also display many of the sleep-disordered cognitive processes that were previously assumed to be unique to the insomnia experience. As such, this review aims to summarise current research findings to address the question "Could cognitive processes be involved in the development and maintenance of DSWPD?" In particular, the presence of cognitive and physiological pre-sleep arousal, sleep-related attentional bias, distorted perception of sleep and daytime functioning, dysfunctional beliefs and safety behaviours will be investigated. As this emerging area of research requires a stronger evidence base, we highlight suggestions for future investigation and provide preliminary practice points for clinicians assessing and treating "insomnia" in patients with DSWPD.

Insomnia disorder is associated with increased amygdala reactivity to insomnia-related stimuli

STUDY OBJECTIVES

Alterations in emotional reactivity may play a key role in the pathophysiology of insomnia disorder (ID). However, only few supporting experimental data are currently available. We evaluated in a hypothesis-driven design whether patients with ID present altered amygdale responses to emotional stimuli related and unrelated to the experience of insomnia and, because of chronic hyperarousal, less habituation of amygdala responses.

DESIGN

Case-control study.

SETTING

Departments of Psychiatry and Psychotherapy and of Radiology of the University of Freiburg Medical Center.

PARTICIPANTS

There were 22 patients with ID (15 females; 7 males; age 40.7 ± 12.6 y) and 38 healthy good sleepers (HGS, 21 females; 17 males; age 39.6 ± 8.9 y).

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

In a functional magnetic resonance imaging session, five different blocks of pictures with varying emotional arousal, valence, and content (insomnia-relatedness) were presented. Pictures were presented twice to test for habituation processes. Results showed that patients with ID, compared to HGS, presented heightened amygdala responses to insomnia-related stimuli. Moreover, habituation of amygdale responses was observed only in HGS, but not in patients with ID who showed a mixed pattern of amygdala responses to the second presentation of the stimuli.

CONCLUSIONS

The results provide evidence for an insomnia-related emotional bias in patients with ID. Cognitive behavior treatment for ID could benefit from strategies dealing with the emotional charge associated with the disorder. Further studies should clarify the role of ID with respect to habituation of amygdala responses.

Kind attention and non-judgment in mindfulness-based cognitive therapy applied to the treatment of insomnia: state of knowledge

Psychophysiological insomnia is characterized by acquired sleep difficulties and/or a state of hypervigilance when going to bed. This mental and physiological condition prevents sleep onset regardless of the presence of anxious or depressive disorders. Despite the fact that cognitive behavioural therapies have been shown to be effective for this disorder, some people are not responding to this treatment. It is therefore important to explore new ways of increasing the effectiveness of current treatments. Approaches based on mindfulness, which promote a non-judgemental acceptance of the living experience, are increasingly reported in the literature to be effective in the treatment of various physical and psychological health conditions, being particularly efficient in reducing the stress and discomfort associated with these problems. This article focuses on some cognitive factors associated with maintaining insomnia and suggests that approaches based on mindfulness, through certain action mechanisms, may help to improve sleep. A review of recent studies on the application of mindfulness-based approaches to treat insomnia is hereby presented. Avenues for future research to improve insomnia treatment protocols based on mindfulness are suggested.

Who is predisposed to insomnia: a review of familial aggregation, stress-reactivity, personality and coping style

Insomnia is a common health complaint world-wide. Insomnia is a risk factor in the development of other psychological and physiological disorders. Therefore understanding the mechanisms which predispose an individual to developing insomnia has great transdiagnostic value. However, whilst it is largely accepted that a vulnerable phenotype exists there is a lack of research which aims to systematically assess the make-up of this phenotype. This review outlines the research to-date, considering familial aggregation and the genetics and psychology of stress-reactivity. A model will be presented in which negative affect (neuroticism) and genetics (5HTTLPR) are argued to lead to disrupted sleep via an increase in stress-reactivity, and further that the interaction of these variables leads to an increase in learned negative associations, which further increase the likelihood of poor sleep and the development of insomnia.

What are you looking at? Moving toward an attentional timeline in insomnia: a novel semantic eye tracking study

STUDY OBJECTIVES

To date, cognitive probe paradigms have been used in different guises to obtain reaction time measurements suggestive of an attention bias towards sleep in insomnia. This study adopts a methodology which is novel to sleep research to obtain a continual record of where the eyes-and therefore attention-are being allocated with regard to sleep and neutral stimuli.

DESIGN

A head mounted eye tracker (Eyelink II,SR Research, Ontario, Canada) was used to monitor eye movements in respect to two words presented on a computer screen, with one word being a sleep positive, sleep negative, or neutral word above or below a second distracter pseudoword. Probability and reaction times were the outcome measures.

PARTICIPANTS

Sleep group classification was determined by screening interview and PSQI (> 8 = insomnia, < 3 = good sleeper) score.

MEASUREMENTS AND RESULTS

Those individuals with insomnia took longer to fixate on the target word and remained fixated for less time than the good sleep controls. Word saliency had an effect with longer first fixations on positive and negative sleep words in both sleep groups, with largest effect sizes seen with the insomnia group.

CONCLUSIONS

This overall delay in those with insomnia with regard to vigilance and maintaining attention on the target words moves away from previous attention bias work showing a bias towards sleep, particularly negative, stimuli but is suggestive of a neurocognitive deficit in line with recent research.

Transient insomnia versus chronic insomnia: a comparison study of sleep-related psychological/behavioral characteristics

OBJECTIVES

Vulnerability to transient insomnia is regarded as a predisposing factor for chronic insomnia. However, most individuals with transient insomnia do not develop chronic insomnia. The current study investigated the differential contributing factors for these two conditions to further the understanding of this phenomenon.

METHOD

Chronic insomnia patients and normal sleepers with high and low vulnerability to transient insomnia completed measures of pre-sleep arousal, dysfunctional sleep beliefs, and sleep-related safety behaviors.

RESULTS

Both cognitive and somatic pre-sleep arousals were identified as significant predictors for transient insomnia. Dysfunctional beliefs regarding worry about insomnia and cognitive arousal were predictors for chronic insomnia. Sleep-related safety behavior, although correlated with insomnia severity, was not a significant predictor for both conditions.

CONCLUSIONS

Dysfunctional beliefs associated with worry and losing control over sleep are the most critical factors in differentiating chronic insomnia from transient insomnia. These factors should be addressed to help prevent individuals with high sleep vulnerability from developing chronic sleep disturbance.

Sleep-related arousal versus general cognitive arousal in primary insomnia

STUDY OBJECTIVES

The present study aimed at further investigating trait aspects of sleep-related cognitive arousal and general cognitive arousal and their association with both objective and subjective sleep parameters in primary insomnia patients.

METHODS

A clinical sample of 182 primary insomnia patients and 54 healthy controls was investigated using 2 nights of polysomnography, subjective sleep variables, and a questionnaire on sleep-related and general cognitive arousal.

RESULTS

Compared to healthy controls, primary insomnia patients showed both more sleep-related and general cognitive arousal. Furthermore, sleep-related cognitive arousal was closely associated with measures of sleep-onset and sleep-maintenance problems, while general cognitive arousal was not.

CONCLUSIONS

Cognitive-behavioral treatment for insomnia might benefit from dedicating more effort to psychological interventions that are able to reduce sleep-related cognitive arousal.

Priming affects poor sleepers but not normal sleepers on an insomnia ambiguity task

With increasing importance being placed on the role of cognitive biases as a maintaining factor in insomnia, the influence of order effects on interpretative responses should be examined and subsequently accounted for. The aim of the present study was to examine whether asking participants about their sleep experiences, prior to testing for a perceptual bias, affects responses on a sleep-related ambiguity task. One hundred and seventeen undergraduate students, blind to the aims of the experiment, were issued either the Dysfunctional Beliefs and Attitudes to Sleep scale (DBAS-10) and Insomnia Severity Index (ISI) before, or following, completion of an Insomnia Ambiguity Task (IAT). As expected, a multivariate analysis of variance showed that the order in which participants completed the task affected the responses on the IAT with those given the DBAS-10 and ISI first, showing greater insomnia-related interpretations than those given the IAT first. However, on closer examination, this effect was evident only for those who were defined as poor sleepers, and that normal sleepers were largely unaffected by the order in which the tests are given. The results are discussed in terms of design and management of sleep-related research protocols involving implicit cognitive tasks.