The attention-intention-effort pathway in the development of psychophysiologic insomnia: a theoretical review

Does Elite Sport Degrade Sleep Quality? A Systematic Review

BACKGROUND

Information on sleep quality and insomnia symptomatology among elite athletes remains poorly systematised in the sports science and medicine literature. The extent to which performance in elite sport represents a risk for chronic insomnia is unknown.

OBJECTIVES

The purpose of this systematic review was to profile the objective and experienced characteristics of sleep among elite athletes, and to consider relationships between elite sport and insomnia symptomatology.

METHODS

Studies relating to sleep involving participants described on a pre-defined continuum of 'eliteness' were located through a systematic search of four research databases: SPORTDiscus, PubMed, Science Direct and Google Scholar, up to April 2016. Once extracted, studies were categorised as (1) those mainly describing sleep structure/patterns, (2) those mainly describing sleep quality and insomnia symptomatology and (3) those exploring associations between aspects of elite sport and sleep outcomes.

RESULTS

The search returned 1676 records. Following screening against set criteria, a total of 37 studies were identified. The quality of evidence reviewed was generally low. Pooled sleep quality data revealed high levels of sleep complaints in elite athletes. Three risk factors for sleep disturbance were broadly identified: (1) training, (2) travel and (3) competition.

CONCLUSION

While acknowledging the limited number of high-quality evidence reviewed, athletes show a high overall prevalence of insomnia symptoms characterised by longer sleep latencies, greater sleep fragmentation, non-restorative sleep, and excessive daytime fatigue. These symptoms show marked inter-sport differences. Two underlying mechanisms are implicated in the mediation of sport-related insomnia symptoms: pre-sleep cognitive arousal and sleep restriction.

Attentional bias modification training for insomnia: A double-blind placebo controlled randomized trial

Background

Attentional bias toward sleep-related information is believed to play a key role in insomnia. If attentional bias is indeed of importance, changing this bias should then in turn have effects on insomnia complaints. In this double-blind placebo controlled randomized trial we investigated the efficacy of attentional bias modification training in the treatment of insomnia.

Method

We administered baseline, post-test, and one-week follow-up measurements of insomnia severity, sleep-related worry, depression, and anxiety. Participants meeting DSM-5 criteria for insomnia were randomized into an attentional bias training group (n = 67) or a placebo training group (n = 70). Both groups received eight training sessions over the course of two weeks. All participants kept a sleep diary for four consecutive weeks (one week before until one week after the training sessions).

Results

There was no additional benefit for the attentional bias training over the placebo training on sleep-related indices/outcome measures.

Conclusions

The absence of the effect may be explained by the fact that there was neither attentional bias at baseline nor any reduction in the bias after the training. Either way, this study gives no support for attentional bias modification training as a stand-alone intervention for ameliorating insomnia complaints.

Predictors of Nightly Subjective-Objective Sleep Discrepancy in Poor Sleepers over a Seven-Day Period

This study sought to examine predictors of subjective/objective sleep discrepancy in poor sleepers. Forty-two individuals with insomnia symptoms (mean age = 36.2 years, 81% female) were recruited to take part in a prospective study which combined seven days of actigraphy with daily assessment of sleep perceptions, self-reported arousal, sleep effort, and mood upon awakening. A high level of intra-individual variability in measures of sleep discrepancy was observed. Multilevel modelling revealed that higher levels of pre-sleep cognitive activity and lower mood upon awakening were significantly and independently predictive of the underestimation of total sleep time. Greater levels of sleep effort predicted overestimation of sleep onset latency. These results indicate that psychophysiological variables are related to subjective/objective sleep discrepancy and may be important therapeutic targets in the management of insomnia.

Priming recognition in good sleepers and in insomniacs

Insomniacs often report memory and concentration problems, but these complaints have not been consistently supported by performance measurements. Furthermore, while the majority of studies have addressed explicit memory, few have investigated the implicit domain, and very little is known concerning other types of implicit memory besides procedural memory, such as priming. Thus, the purpose of the study was to investigate priming effect for visual stimuli in insomniacs and good sleepers. Twenty-three insomniacs and 20 good sleepers performed a visual priming task in which they were asked to name new and old pictures presented at nine ascending levels of spatial filtering. Both neutral and sleep-related stimuli were used, as previous research evidenced an attentional bias for sleep-related stimuli. Visual priming effect was observed in both groups, suggesting that poor sleep quality does not affect this type of implicit memory. However, the identification process in insomniacs is influenced by the nature of the stimulus to identify: insomniacs recognized both new and old sleep-related stimuli at lower spatial frequencies compared with good sleepers. The tendency to selectively attend to sleep-related stimuli may influence top-down processes occurring during identification of filtering stimuli, by determining a pre-allocation of attentional resources and facilitating identification processes even when sensorial information is scant. Differences in the identification processes of sleep-related stimuli compared with neutral ones should be carefully taken into account as possible pre-clinical markers of insomnia in poor sleepers.

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.

Clinical Sleep-Wake Disorders II: Focus on Insomnia and Circadian Rhythm Sleep Disorders

Insomnia and circadian rhythm sleep disorders affect large proportions of the population and have pronounced effects on quality of life and daytime performance. While the neurobiology of insomnia is not yet fully understood, circadian rhythm sleep disorders are assumed to be caused by a mismatch between the individual circadian phase position and the desired sleep-wake schedule. Benzodiazepines and non-benzodiazepine positive allosteric GABA_A receptor modulators improve sleep onset and maintenance in the short-term treatment of insomnia. However, tolerance and dependence are important side effects. Sedating antidepressants are frequently prescribed for insomnia, however, only few randomised controlled trials have been published so far. Melatonin and melatonin receptor agonists are considered to be an option for the treatment of insomnia especially because of their minimal abuse potential and safety. First data on orexin (aka hypocretin) receptor antagonists are promising, however, the risk-benefit ratio needs to be further evaluated. With respect to circadian rhythm sleep disorders, there is solid evidence from meta-analyses supporting the use of melatonin in jet lag disorder to accelerate entrainment to the new time zone, and in delayed sleep phase disorder to advance sleep-wake rhythms. In addition to that, there is evidence supporting the use of melatonin in patients with shift work disorder in order to promote daytime sleep after night shifts.

Does Consciousness Disappear in Dreamless Sleep?

Consciousness is often said to disappear in deep, dreamless sleep. We argue that this assumption is oversimplified. Unless dreamless sleep is defined as unconscious from the outset there are good empirical and theoretical reasons for saying that a range of different types of sleep experience, some of which are distinct from dreaming, can occur in all stages of sleep. We introduce a novel taxonomy for describing different kinds of dreamless sleep experiences and suggest research methods for their investigation. Future studies should focus on three areas: memory consolidation, sleep disorders, and sleep state (mis)perception. Our proposal suggests new directions for sleep and dream science, as well as for the neuroscience of consciousness, and can also inform the diagnosis and treatment of sleep disorders.

Nocturnal Polyuria in Older Women with Urge Urinary Incontinence: Role of Sleep Quality, Time in Bed and Medications Used

PURPOSE

Nocturia is common and bothersome in older adults, especially those who are also incontinent. Since nocturnal polyuria is a major contributor, we examined factors associated with nocturnal polyuria in this population to identify those possibly amenable to intervention.

MATERIALS AND METHODS

We analyzed baseline data from 2 previously completed studies of urge urinary incontinence. The studies involved 284 women (mean age ± SD 72.9 ± 7.9 years) who also completed 3-day voiding diaries. Participants with a nocturnal polyuria index greater than 33% were categorized as having nocturnal polyuria (nocturnal polyuria index = nocturnal urinary volume per 24-hour urine volume). Associations between nocturnal polyuria and various demographic, clinical and sleep related parameters were determined.

RESULTS

Overall 55% of the participants had nocturnal polyuria. Multivariable regression analysis revealed that age, body mass index, use of angiotensin converting enzyme inhibitor/angiotensin receptor blocker, time spent in bed and duration of first uninterrupted sleep were independent correlates of nocturnal polyuria. Participants with a larger nocturnal excretion reported a shorter duration of uninterrupted sleep before first awakening to void and worse sleep quality despite spending similar time in bed.

CONCLUSIONS

Body mass index, use of angiotensin converting enzyme inhibitor/angiotensin receptor blockers, time in bed and duration of uninterrupted sleep before first awakening to void are independently associated with nocturnal polyuria in older women with urge urinary incontinence, and are potentially modifiable. These findings also confirm the association between sleep and nocturnal polyuria. Further studies should explore whether interventions to reduce nocturnal polyuria and/or increase the duration of uninterrupted sleep before first awakening to void would help to improve sleep quality in this population and thereby reduce or eliminate the need for sedative hypnotics.

Development of the Pain-Related Beliefs and Attitudes about Sleep (PBAS) Scale for the Assessment and Treatment of Insomnia Comorbid with Chronic Pain

STUDY OBJECTIVES

Dysfunctional beliefs and attitudes about sleep is a cognitive-behavioral factor central to the development and perpetuation of insomnia. Previous works to unravel the complex interrelationship between pain and insomnia have not explored the role of inflexible beliefs about the sleep-pain interaction, possibly due to a lack of a valid instrument for doing so. The current study evaluated the psychometric and functional properties of a 10-item Pain-Related Beliefs and Attitudes about Sleep (PBAS) scale.

METHODS

The PBAS scale was administered to four clinical samples of chronic pain patients with comorbid insomnia: to examine the scale's psychometric properties (n = 137), test-retest reliability (n = 26), sensitivity to treatment (n = 20), and generalizability (n = 62). All participants completed the PBAS together with validated measures of pain interference, insomnia severity, and cognitive-behavioral processes hypothesized to underpin insomnia.

RESULTS

The PBAS scale was found to be reliable, with adequate internal consistency and temporal stability. Factor analysis suggested a 2-factor solution representing beliefs about "pain as the primary cause of insomnia" and the "inevitable consequences of insomnia on pain and coping." The PBAS total score was positively correlated with scores from the Insomnia Severity Index (ISI) scale, Dysfunctional Beliefs and Attitudes about Sleep (DBAS) scale, and the Anxiety and Preoccupation about Sleep Questionnaire (APSQ). It was a significant predictor of insomnia severity and pain interference. A significant reduction in PBAS was also observed in patients after receiving a hybrid cognitive-behavioral intervention for both pain and insomnia.

CONCLUSIONS

Pain-related sleep beliefs appear to be an integral part of chronic pain patients' insomnia experience. The PBAS is a valid and reliable instrument for evaluating the role of these beliefs in chronic pain patients.

Preferential attention towards the eye-region amongst individuals with insomnia

People with insomnia often perceive their own facial appearance as more tired compared with the appearance of others. Evidence also highlights the eye-region in projecting tiredness cues to perceivers, and tiredness judgements often rely on preferential attention towards this region. Using a novel eye-tracking paradigm, this study examined: (i) whether individuals with insomnia display preferential attention towards the eye-region, relative to nose and mouth regions, whilst observing faces compared with normal-sleepers; and (ii) whether an attentional bias towards the eye-region amongst individuals with insomnia is self-specific or general in nature. Twenty individuals with DSM-5 Insomnia Disorder and 20 normal-sleepers viewed 48 neutral facial photographs (24 of themselves, 24 of other people) for periods of 4000 ms. Eye movements were recorded using eye-tracking, and first fixation onset, first fixation duration and total gaze duration were examined for three interest-regions (eyes, nose, mouth). Significant group × interest-region interactions indicated that, regardless of the face presented, participants with insomnia were quicker to attend to, and spent more time observing, the eye-region relative to the nose and mouth regions compared with normal-sleepers. However, no group × face × interest-region interactions were established. Thus, whilst individuals with insomnia displayed preferential attention towards the eye-region in general, this effect was not accentuated during self-perception. Insomnia appears to be characterized by a general, rather than self-specific, attentional bias towards the eye-region. These findings contribute to our understanding of face perception in insomnia, and provide tentative support for cognitive models of insomnia demonstrating that individuals with insomnia monitor faces in general, with a specific focus around the eye-region, for cues associated with tiredness.

I sleep with my Mind's eye open: Cognitive arousal and overgeneralization underpin the misperception of sleep

BACKGROUND AND OBJECTIVES

Misperception of sleep (e.g., underestimation of sleep time relative to objective measures) is a common feature of insomnia and other psychopathologies. To elucidate the mechanisms underlying this tendency, we examined the role of pre-sleep cognitive arousal and overgeneralization.

METHODS

We monitored the sleep of 54 community dwellers (the majority being university students), using actigraphy and a sleep diary for 7 days. Immediately after this period, the participants provided an additional global evaluation of their sleep for the past week. In this global evaluation, participants were asked to estimate their average number of hours of sleep and the duration of time taken to fall asleep (sleep onset latency) across the past seven nights.

RESULTS

Single-night misperceptions (difference between actigraphy and sleep diary estimations) of sleep time and sleep onset latency were significantly associated with pre-sleep cognitive arousal, but not with overgeneralization. In contrast, global misperception of sleep (difference between sleep diary and global estimations) were associated with overgeneralization, but not with cognitive arousal.

LIMITATIONS

Our sample mainly consisted of female university students, which limits the generalizability of the results.

CONCLUSIONS

Misperception of sleep occurs in two cases: (1) in the case of a single night due to excessive arousal, and (2) in the case of multiple nights due to overgeneralization.

Objective sleep disturbances are associated with greater waking resting-state connectivity between the retrosplenial cortex/ hippocampus and various nodes of the default mode network

BACKGROUND

Psychological models highlight the bidirectional role of self-referential processing, introspection, worry and rumination in the development and maintenance of insomnia; however, little is known about the underlying neural substrates. Default mode network (DMN) functional connectivity has been previously linked to these cognitive processes.

METHODS

We used fMRI to investigate waking DMN functional connectivity in a well-characterized sample of patients with primary insomnia (PI) and good sleeper controls.

RESULTS

We included 20 patients with PI (8 men and 12 women, mean age 42.7 ± 13.4 yr) and 20 controls (8 men and 12 women, mean age 44.1 ± 10.6 yr) in our study. While no between-group differences in waking DMN connectivity were observed, exploratory analyses across all participants suggested that greater waking connectivity between the retrosplenial cortex/hippocampus and various nodes of the DMN was associated with lower sleep efficiency, lower amounts of rapid eye movement sleep and greater sleep-onset latency.

LIMITATIONS

Owing to the cross-sectional nature of the study, conclusions about causality cannot be drawn.

CONCLUSION

As sleep disturbances represent a transdiagnostic symptom that is characteristic of nearly all psychiatric disorders, our results may hold particular relevance to previous findings of increased DMN connectivity levels in patients with psychiatric disorders.

Neurobiological Correlates of Psychological Treatments for Insomnia

Abstract. Sleep disorders and sleep disturbances are considered nowadays a major public health problem. Within sleep problems, insomnia is the most common health complaint. The maintenance of insomnia symptoms may lead to a clinical disorder – Insomnia Disorder (ID). A significant amount of literature has shown the efficacy and effectiveness of psychological treatments for ID. Often, the evaluation of therapeutic processes and outcomes focuses on subjective measures such as sleep diaries. In this work, we review the few published studies that evaluate modifications in neurobiological domain related to evidence-based psychological interventions, namely cognitive-behavioral therapy for insomnia (CBT-I). The search was carried out consulting Scopus, PubMed, and ISI Web of Knowledge databases. Only 12 studies were found. From the reviewed papers it was observed that the results are diverse, perhaps due to significant differences pertaining to the methodologies used. However, one interesting finding emerged: daytime experiments on insomnia comprising mainly cognitive tasks denoted hypofunction in ID patients, whereas nighttime experiments mainly associated with affective/emotional tasks denoted hyperarousal. We suggest that the study of the neural changes prompted by CBT-I is a major topic in the domain of psychotherapy and sleep medicine. Despite the scarce studies on neurobiological mechanisms of CBT-I, the results achieved until now are promising and should be taken into account in the future. Nonetheless, more research on this topic is needed.

Factors associated with self-reported need for treatment of sleeping difficulties: a survey of the general Swedish population

OBJECTIVE

This study aims to investigate factors associated with the self-reported need for treatment of sleeping difficulties in the general population.

METHODS

This study consisted of a cross-sectional telephone survey of 1550 people randomly selected from the total population of Sweden. The survey, conducted by the Swedish national statistics agency, Statistics Sweden, was completed by 1115 people aged 18-85 years. Participants were asked about sleep patterns, daytime symptoms, physical and mental health disorders, use of prescribed hypnotics, help-seeking behaviors, and sociodemographic characteristics. They were also asked whether they thought they needed treatment for sleeping difficulties.

RESULTS

A total of 12.5% of the participants reported a need for treatment because of sleeping difficulties. Significantly more women than men reported such a need (OR 1.46, 95% CI 1.02-2.10). Additionally, in univariate analyses, older age (age 60-69), sick leave, retirement, and unemployment were associated with a self-reported need for treatment, as were several sleep complaints, daytime symptoms, and physical and mental health disorders. A logistic regression model showed that difficulty initiating sleep (OR 6.29, 95% CI 3.67-10.78) was the factor most strongly associated with a self-reported need for treatment for sleeping difficulties. Other important factors were nonrestorative sleep (OR 3.70, 95% CI 2.05-6.69), mental health disorders (OR 3.01, 95% CI 1.59-5.67), and fatigue (OR 2.95, 95% CI 1.53-5.68).

CONCLUSIONS

There was considerable self-reported need for treatment for sleeping difficulties in the population. Difficulty initiating sleep was the factor most strongly associated with this need, followed by nonrestorative sleep, mental health disorders, and fatigue.

Treating Sleep Problems in Patients with Schizophrenia

BACKGROUND

Sleep disturbance is increasingly recognized as a major problem for patients with schizophrenia but it is rarely the direct focus of treatment. The main recommended treatment for insomnia is cognitive behavioural therapy, which we have been evaluating for patients with current delusions and hallucinations in the context of non-affective psychosis.

AIMS

In this article we describe the lessons we have learned about clinical presentations of sleep problems in schizophrenia and the adaptations to intervention that we recommend for patients with current delusions and hallucinations.

METHOD

Twelve factors that may particularly contribute to sleep problems in schizophrenia are identified. These include delusions and hallucinations interfering with sleep, attempts to use sleep as an escape from voices, circadian rhythm disruption, insufficient daytime activity, and fear of the bed, based upon past adverse experiences. Specific adaptations for psychological treatment related to each factor are described.

CONCLUSIONS

Our experience is that patients want help to improve their sleep; sleep problems in schizophrenia should be treated with evidence-based interventions, and that the interventions may have the added benefit of lessening the psychotic experiences. A treatment technique hierarchy is proposed for ease of translation to clinical practice.

[Chronic insomnia: treatment methods based on the current "3P" model of insomnia]

Authors consider one of the popular models of the pathogenesis of chronic insomnia--"3P" model. It explains the origin and course of insomnia on the basis of interaction of three factors: predisposing, precipitating and perpetuating. The role of each group of factors and its connection to the cerebral hyperarousal state is discussed. Different variants of cognitive-behavioral therapy and pharmacological treatment of chronic insomnia are described.

Perfectionistic Tendencies in Insomnia Patients' Behavior During Psychometric Testing

According to self-report questionnaire studies, insomnia patients differ from healthy controls with respect to several personality traits. The current study aimed at exploring how these personality traits may translate into behavior. Insomnia patients' behavior during psychometric testing (n = 163) was investigated in comparison to healthy controls (n = 81), patients with other sleep disorders (n = 80), and patients with obsessive-compulsive disorder (n = 36). In line with our hypotheses, insomnia patients made more additional comments than healthy controls and more corrections than patients with other sleep disorders during sleep-related questionnaire completion. Furthermore, insomnia patients calculated the sum score of a depression questionnaire more frequently than both healthy controls and patients with other sleep disorders. These findings further support the assumption of an altered personality profile in patients with primary insomnia. Future work should aim to elucidate what personality factors these novel behavioral markers may reflect.

Information processing during NREM sleep and sleep quality in insomnia

Insomnia sufferers (INS) are cortically hyperaroused during sleep, which seems to translate into altered information processing during nighttime. While information processing, as measured by event-related potentials (ERPs), during wake appears to be associated with sleep quality of the preceding night, the existence of such an association during nighttime has never been investigated. This study aims to investigate nighttime information processing among good sleepers (GS) and INS while considering concomitant sleep quality. Following a multistep clinical evaluation, INS and GS participants underwent 4 consecutive nights of PSG recordings in the sleep laboratory. Thirty nine GS (mean age 34.56±9.02) and twenty nine INS (mean age 43.03±9.12) were included in the study. ERPs (N1, P2, N350) were recorded all night on Night 4 (oddball paradigm) during NREM sleep. Regardless of sleep quality, INS presented a larger N350 amplitude during SWS (p=0.042) while GS showed a larger N350 amplitude during late-night stage 2 sleep (p=0.004). Regardless of diagnosis, those who slept objectively well showed a smaller N350 amplitude (p=0.020) while those who slept subjectively well showed a smaller P2 (p<0.001) and N350 amplitude (p=0.006). Also, those who reported an objectively bad night as good showed smaller P2 (p< 0.001) and N350 (p=0.010) amplitudes. Information processing seems to be associated with concomitant subjective and objective sleep quality for both GS and INS. However, INS show an alteration in information processing during sleep, especially for inhibition processes, regardless of their sleep quality.

Remember to do: insomnia versus control groups in a prospective memory task

Primary insomnia is characterized by difficulty in falling asleep and/or remaining asleep, by early morning awakening and/or nonrestorative sleep, and resultant daytime dysfunction in the absence of specific physical, mental, or substance-related causes. However, the studies on daytime cognitive functioning of insomnia patients report inconclusive results. This retrospective study aimed to compare the performance of insomnia patients (N = 54) to that of controls (N = 113) in a naturalistic prospective memory task. Task performance was defined by the percentage of times the event-marker button of an actigraph was pressed, at lights-off time and at wake-up time. The performance pattern in the prospective memory task was similar in both groups. In addition, the task was performed better at lights-off time than at wake-up time regardless of group. Post-hoc subgroup analysis showed that there were more insomnia patients who performed the task perfectly (i.e., 100%) than controls. Performance at wake-up time was significantly correlated to objective sleep quality (i.e., sleep efficiency) only in insomnia patients.

Cortical Structural Connectivity Alterations in Primary Insomnia: Insights from MRI-Based Morphometric Correlation Analysis

The etiology and maintenance of insomnia are proposed to be associated with increased cognitive and physiological arousal caused by acute stressors and associated cognitive rumination. A core feature of such hyperarousal theory of insomnia involves increased sensory processing that interferes with the onset and maintenance of sleep. In this work, we collected structural magnetic resonance imaging data from 35 patients with primary insomnia and 35 normal sleepers and applied structural covariance analysis to investigate whether insomnia is associated with disruptions in structural brain networks centered at the sensory regions (primary visual, primary auditory, and olfactory cortex). As expected, insomnia patients showed increased structural covariance in cortical thickness between sensory and motor regions. We also observed trends of increased covariance between sensory regions and the default-mode network, and the salience network regions, and trends of decreased covariance between sensory regions and the frontoparietal working memory network regions, in insomnia patients. The observed changes in structural covariance tended to correlated with poor sleep quality. Our findings support previous functional neuroimaging studies and provide novel insights into variations in brain network configuration that may be involved in the pathophysiology of insomnia.

Insomnia disorder

Insomnia disorder affects a large proportion of the population on a situational, recurrent or chronic basis and is among the most common complaints in medical practice. The disorder is predominantly characterized by dissatisfaction with sleep duration or quality and difficulties initiating or maintaining sleep, along with substantial distress and impairments of daytime functioning. It can present as the chief complaint or, more often, co-occurs with other medical or psychiatric disorders, such as pain and depression. Persistent insomnia has been linked with adverse long-term health outcomes, including diminished quality of life and physical and psychological morbidity. Despite its high prevalence and burden, the aetiology and pathophysiology of insomnia is poorly understood. In the past decade, important changes in classification and diagnostic paradigms have instigated a move from a purely symptom-based conceptualization to the recognition of insomnia as a disorder in its own right. These changes have been paralleled by key advances in therapy, with generic pharmacological and psychological interventions being increasingly replaced by approaches that have sleep-specific and insomnia-specific therapeutic targets. Psychological and pharmacological therapies effectively reduce the time it takes to fall asleep and the time spent awake after sleep onset, and produce a modest increase in total sleep time; these are outcomes that correlate with improvements in daytime functioning. Despite this progress, several challenges remain, including the need to improve our knowledge of the mechanisms that underlie insomnia and to develop more cost-effective, efficient and accessible therapies.

Open-Loop Neurofeedback Audiovisual Stimulation: A Pilot Study of Its Potential for Sleep Induction in Older Adults

This pilot study tested the efficacy of a 30-min audio-visual stimulation (AVS) program for the treatment of chronic insomnia in older adults. Chronic insomnia has been conceptualized as entailing increased cortical high frequency EEG activity at sleep onset and during NREM sleep. We hypothesized that an AVS program gradually descending from 8 to 1 Hz would potentially reduce the excessive cortical activation that is thought to contribute to difficulties with initiating and maintaining sleep. Accordingly, we conducted an intervention study of AVS using a pre-post design. Eight older adults (88 ± 8.7 years) complaining of chronic insomnia self-administered a 30-min AVS program nightly at bedtime for one month. Sleep was assessed at baseline and throughout the 4-week intervention. After using AVS for 4 weeks, significant improvement was reported in insomnia symptoms (ISI, p = 0.002) and sleep quality (PSQI, p = 0.004); with moderate to large effect sizes (Partial Eta2: 0.20-0.55)(Cohen's d: 0.7-2.3). The training effect (self-reported sleep improvement) was observed at the end of week one and persisted through the 1-month intervention. The results from this pilot study suggest that further exploration of AVS as a treatment for insomnia is warranted.

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.

Psychiatric comorbidity and aspects of cognitive coping negatively predict outcome in cognitive behavioral treatment of psychophysiological insomnia

Cognitive behavioral treatment is the gold standard treatment for insomnia, although a substantial group does not respond. We examined possible predictors for treatment outcome in psychophysiological insomniacs, with a focus on the presence of clearly defined psychiatric comorbidity. This was a longitudinal uncontrolled case series study comprising 60 patients with chronic psychophysiological insomnia consecutively referred to a tertiary sleep medicine center, to receive cognitive behavioral treatment for insomnia (CBT-I). Remission of insomnia was defined as a posttreatment Insomnia Severity Index score below 8. As an alternative outcome, we used a clinically relevant decrease on the Insomnia Severity Index (drop of > 7 points). Personality, coping, and social support questionnaires were assessed before the start of the treatment and were compared between treatment responders and nonresponders. To examine whether these variables were predictive for negative treatment outcome, logistic regression analyses were applied. Treatment nonresponders had a significantly higher prevalence of psychiatric comorbidity. Logistic regression analyses showed that the presence of psychiatric comorbidity was strongly predictive for negative treatment outcome (odds ratios: 20.6 and 10.3 for the 2 outcome definitions). Additionally, higher scores on the cognitive coping strategy called "refocus on planning" were associated with worse CBT-I outcome. Current psychiatric comorbidity is strongly predictive for negative treatment outcome. The presence of a psychiatric disorder must therefore be one of the leading arguments in the choice of treatment modalities that are being proposed to patients with insomnia.

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.

The pathophysiology of insomnia

Insomnia disorder is characterized by chronic dissatisfaction with sleep quantity or quality that is associated with difficulty falling asleep, frequent nighttime awakenings with difficulty returning to sleep, and/or awakening earlier in the morning than desired. Although progress has been made in our understanding of the nature, etiology, and pathophysiology of insomnia, there is still no universally accepted model. Greater understanding of the pathophysiology of insomnia may provide important information regarding how, and under what conditions, the disorder develops and is maintained as well as potential targets for prevention and treatment. The aims of this report are (1) to summarize current knowledge on the pathophysiology of insomnia and (2) to present a model of the pathophysiology of insomnia that considers evidence from various domains of research. Working within several models of insomnia, evidence for the pathophysiology of the disorder is presented across levels of analysis, from genetic to molecular and cellular mechanisms, neural circuitry, physiologic mechanisms, sleep behavior, and self-report. We discuss the role of hyperarousal as an overarching theme that guides our conceptualization of insomnia. Finally, we propose a model of the pathophysiology of insomnia that integrates the various types of evidence presented.

The development of insomnia or the plasticity of good sleep? A preliminary study of acute changes in sleep and insomnia resulting from an analogue trauma

The present preliminary study aimed to shed light on the mechanisms underlying the development of insomnia. An analogue stressor (i.e., trauma video) was used to prevent presleep cognitive de-arousal. Subsequent changes in nocturnal sleep and sleep-related attentional processing were examined. Thirty-four participants were randomly assigned to either a cognitive arousal (trauma video; age: M = 22.9, SD = 4.3, 6 male, 11 female) or control (pleasant video; age: M = 23.8, SD = 5.8, 7 male, 10 female) condition. Although no significant differences were found for presleep cognitive de-arousal (p = .39), the cognitive arousal group experienced a significant worsening in sleep latency (p = .048, partial η(2) = .12) and an increase in sleep-related attentional bias (p = .032, d = 0.51) following the manipulation. However, changes in sleep and attentional bias were not maintained. Vulnerability to stress did not significantly account for any change in attentional bias, arousal, or sleep. These findings challenge current conceptualizations of the development of insomnia, yet also supporting the notion that good sleep is a default state that protects individuals from sleep disturbance.

How are normal sleeping controls selected? A systematic review of cross-sectional insomnia studies and a standardized method to select healthy controls for sleep research

There appears to be some inconsistency in how normal sleepers (controls) are selected and screened for participation in research studies for comparison with insomnia patients. The purpose of the current study is to assess and compare methods of identifying normal sleepers in insomnia studies, with reference to published standards. We systematically reviewed the literature on insomnia patients, which included control subjects. The resulting 37 articles were systematically reviewed with reference to the five criteria for normal sleep specified by Edinger et al. In summary, these criteria are as follows: evidence of sleep disruption, sleep scheduling, general health, substance/medication use, and other sleep disorders. We found sleep diaries, polysomnography (PSG), and clinical screening examinations to be widely used with both control subjects and insomnia participants. However, there are differences between research groups in the precise definitions applied to the components of normal sleep. We found that none of the reviewed studies applied all of the Edinger et al. criteria, and 16% met four criteria. In general, screening is applied most rigorously at the level of a clinical disorder, whether physical, psychiatric, or sleep. While the Edinger et al. criteria seem to be applied in some form by most researchers, there is scope to improve standards and definitions in this area. Ideally, different methods such as sleep diaries and questionnaires would be used concurrently with objective measures to ensure normal sleepers are identified, and descriptive information for control subjects would be reported. Here, we have devised working criteria and methods to be used for the assessment of normal sleepers. This would help clarify the nature of the control group, in contrast to insomnia subjects and other patient groups.

Patients with primary insomnia in the sleep laboratory: do they present with typical nights of sleep?

The validity of sleep laboratory investigations in patients with insomnia is important for researchers and clinicians. The objective of this study was to examine the first-night effect and the reverse first-night effect in patients with chronic primary insomnia compared with good sleeper controls. A retrospective comparison of a well-characterised sample of 50 patients with primary insomnia and 50 good sleeper controls was conducted with respect to 2 nights of polysomnography, and subjective sleep parameters in the sleep laboratory and the home setting. When comparing the first and second sleep laboratory night, a significant first-night effect was observed across both groups in the great majority of the investigated polysomnographic and subjective variables. However, patients with primary insomnia and good sleeper controls did not differ with respect to this effect. Regarding the comparison between the sleep laboratory nights and the home setting, unlike good sleeper controls, patients with primary insomnia reported an increased subjective sleep efficiency on both nights (in part due to a reduced bed time) and an increased subjective total sleep time on the second night. These results suggest that even the second sleep laboratory night does not necessarily provide clinicians and researchers with a representative insight into the sleep perception of patients with primary insomnia. Future studies should investigate whether these findings also hold for other patient populations.

Reduced anterior internal capsule white matter integrity in primary insomnia

Chronic insomnia is one of the most prevalent central nervous system diseases, however, its neurobiology is poorly understood. Up to now, nothing is known about the integrity of white matter tracts in insomnia patients. In this study, diffusion tensor imaging (DTI) was used in a well-characterized sample of primary insomnia (PI) patients and good sleeper controls to fill this void. Voxelwise between-group comparisons of fractional anisotropy (FA) were performed in 24 PI patients (10 males; 14 females; 42.7 ± 14.5 years) and 35 healthy good sleepers (15 males; 20 females; 40.1 ± 9.1 years) with age and sex as covariates. PI patients showed reduced FA values within the right anterior internal capsule and a trend for reduced FA values in the left anterior internal capsule. The results suggest that insomnia is associated with a reduced integrity of white matter tracts in the anterior internal capsule indicating that disturbed fronto-subcortical connectivity may be a cause or consequence of the disorder.

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.

Cognitive impairment in individuals with insomnia: clinical significance and correlates

STUDY OBJECTIVES

The aims of this study were to (1) investigate the nature of cognitive impairment in individuals with insomnia, (2) document their clinical significance, (3) examine their correlates, and (4) explore differences among individuals with insomnia with and without cognitive complaints.

DESIGN

Participants underwent 3 consecutive nights of polysomnography. On the morning following the third night, they completed a battery of questionnaires and neuropsychological tests.

PARTICIPANTS

The sample included 25 adults with primary insomnia (mean age: 44.4 ± 11.5 y, 56% women) and 16 controls (mean age: 42.8 ± 12.9 y, 50% women) matched for sex, age, and education.

INTERVENTION

N/A.

MEASUREMENT AND RESULTS

Participants completed neuropsychological tests covering attention, memory, working memory, and executive functions, as well as questionnaires assessing the subjective perception of performance, depression, anxiety, fatigue, sleepiness, and hyperarousal. There were significant group differences for the attention and episodic memory domains. Clinically significant deficits were more frequent in the insomnia group. Within the insomnia group, individuals with cognitive complaints exhibited significantly poorer performance on a larger number of neuropsychological variables. All impaired aspects of performance were significantly associated with either subjective or objective sleep continuity, and some were also independently related to sleep microstructure (i.e., relative power for alpha frequencies) or selected psychological variables (i.e., beliefs or arousal).

CONCLUSIONS

These findings suggest clinically significant alterations in attention and episodic memory in individuals with insomnia. Objective deficits were more pronounced and involved more aspects of performance in a subgroup of individuals with cognitive complaints. These deficits appear associated with sleep continuity, and may also be related to sleep microstructure and dysfunctional beliefs.

[Insomnia--state of the science]

Diagnostic systems such as the international classification of diseases (ICD-10) or the diagnostic and statistical manual of mental disorders (DSM IV) have frequently been criticized as not adequately reflecting the complexity and heterogeneity of insomnia. Progress was made through the introduction of the international classification of sleep disorders (ICSD-2) and the research diagnostic criteria (RDC). The DSM-5 introduced the new category of insomnia disorder, thus relinquishing the traditional dichotomy of primary versus secondary insomnia. Recent basic research indicates that genetic and epigenetic factors are involved in the etiology of insomnia; the so-called three P model (i.e. predisposing, precipitating and perpetuating factors) and the hyperarousal concept have gained much attention in trying to explain the pathophysiology of insomnia. With respect to the cognitive-behavioral therapy of insomnia (CBT-I), a plethora of empirical evidence supports the first-line character of this type of treatment for insomnia. Unfortunately, CBT-I is still administered to only a minority of afflicted patients, probably due to a lack of resources in the healthcare system. As a consequence, stepped-care models to improve insomnia therapy encompass self-help programs, internet-based treatment avenues, community-centered activities (specially trained nurses) and as a last resort medical specialists/psychotherapists and sleep experts to deal with insomnia.