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.     

Attentional bias in people with acute versus persistent insomnia secondary to cancer

This study investigated the role of attentional bias in the development of persistent insomnia. Two groups of people with cancer who developed sleep-onset problems 0-3 months and 12-18 months after diagnosis completed a computerized emotional Stroop task comprising cancer-related and sleep-related word cues and self-complete measures. Both groups demonstrated attentional bias for cancer-related words, but only the persistent insomnia group demonstrated attentional bias for sleep-related words. High levels of presleep cognitive arousal were evident in both groups despite lower levels of psychological distress in the persistent insomnia group. Results suggest that secondary, sleep-related mental preoccupation may inhibit recovery to normal sleep after stress-related acute sleep disturbance. Findings are discussed in relation to current models of insomnia.     

Attentional Bias in People With Acute Versus Persistent Insomnia Secondary to Cancer

This study investigated the role of attentional bias in the development of persistent insomnia. Two groups of people with cancer who developed sleep-onset problems 0-3 months and 12-18 months after diagnosis completed a computerized emotional Stroop task comprising cancer-related and sleep-related word cues and self-complete measures. Both groups demonstrated attentional bias for cancer-related words, but only the persistent insomnia group demonstrated attentional bias for sleep-related words. High levels of presleep cognitive arousal were evident in both groups despite lower levels of psychological distress in the persistent insomnia group. Results suggest that secondary, sleep-related mental preoccupation may inhibit recovery to normal sleep after stress-related acute sleep disturbance. Findings are discussed in relation to current models of insomnia.     

The Impact of Sleep-Related Attentional Bias on Polysomnographically Measured Sleep in Primary Insomnia

Study Objectives:

Although sleep-related attentional bias has been shown to be evident in primary insomnia, the association with objectively measured sleep has not been investigated. In the present study, we used polysomnography (PSG) to fill this void.

Design:

Patients with primary insomnia and healthy controls were studied using a visual dot probe task (VDP) and an emotional Stroop task (EST). Additionally, polysomnography was carried out in a sub-sample (n = 22) of patients in the subsequent night.

Setting:

Department of Psychiatry and Psychotherapy of the University of Freiburg Medical Center.

Participants:

Thirty patients with primary insomnia and 30 matched healthy controls.

Interventions:

N/A

Measurements and Results:

Patients with primary insomnia demonstrated a significant sleep-related attentional bias compared to controls in the EST but no significant group effects were found for the VDP. VDP attentional bias scores were positively correlated with measures of sleep pressure, including total sleep time, sleep efficiency, and the amount of slow wave sleep. EST attentional bias scores were not correlated with subsequent PSG parameters, and we did not observe a correlation between attentional bias scores on the two tasks.

Conclusions:

The unexpected relationship between increased attentional bias, in the VDP task, and improved markers of sleep duration and continuity, may be indicative of a homeostatic craving for sleep in those with high attentional bias. This awaits further testing in multiple night studies, to shed light on the mechanisms and implications of sleep-related attentional bias.

Citation:

Spiegelhalder K; Kyle SD; Feige B; Prem M; Nissen C; Espie CA; Riemann D. The impact of sleep-related attentional bias on polysomnographically measured sleep in primary insomnia. SLEEP 2010;33(1):107-112.     

Verarbeitung schlafbezogener Stimuli

Previous work suggests that people with poor sleep quality, especially patients with primary insomnia, show an attentional preference for sleep-related stimuli (sleep-related attentional bias). Studies investigating this effect have generally used standardised reaction time experiments, in which the effects of a large number of sleep-related stimuli were averaged. Here, we analysed the data of two studies in order to investigate the contribution of single sleep-related stimuli (words) to sleep-related attentional bias. Results showed that effect sizes of the stimuli were relatively stable between the two studies. Knowing effect sizes of individual stimuli is important for the construction of future attentional paradigms, as well as providing a better understanding of the magnitude and content of sleep-related attentional bias.     

Attentional bias towards sleep‐related stimuli in insomnia disorder: a behavioural and ERP study

Many studies have used behavioural experiments to show an attentional bias towards sleep‐related stimuli in people with insomnia disorder. A measurement of event‐related potential is needed to investigate the cognitive processing mechanism of the attentional process. The present study used the emotional Stroop paradigm and event‐related potentials to measure attentional bias towards sleep‐negative, sleep‐positive and sleep‐unrelated neutral words. The study comprised 16 participants with insomnia disorder and 15 participants who were good sleepers. Behavioural data indicated that there was a significant interference effect of sleep‐positive words between the insomnia group and the good sleepers, and a marginally significant interference effect from sleep‐negative words between groups. In the insomnia group, event‐related potential data showed that sleep‐negative words elicited higher amplitudes of P1 and N1 components than did sleep‐positive and sleep‐unrelated words. Our results provide evidence for the early cognitive processing of sleep‐negative stimuli, which suggests that the psychological treatment of insomnia could benefit from addressing early hypervigilance towards these stimuli.     

Who is pre‐occupied with sleep? A comparison of attention bias in people with psychophysiological insomnia,delayed sleep phase syndrome and good sleepers using the induced change blindness paradigm

Cognitive models of insomnia suggest that selective attention may be involved in maintaining the disorder. However, direct assessment of selective attention is limited. Using the inducing change blindness (ICB) paradigm we aimed to determine whether there is attentional preference for sleep-related stimuli in psychophysiological insomnia (PI) relative to delayed sleep phase syndrome (DSPS) and good sleepers (GS). In the ICB task, a visual scene, comprising both sleep-related and neutral stimuli, 'flickers' back and forth with one element (sleep or neutral) of the scene changing between presentations. Therefore, a 2 x 3 totally between-participants design was employed. The dependent variable was the number of flickers it took for the participant to identify the change. Ninety individuals (30 per group) were classified using ICSD-R criteria, self-report diaries and wrist actigraphy. As predicted, PI detected a sleep-related change significantly quicker than DSPS and GS, and significantly quicker than a sleep-neutral change. Unexpectedly, DSPS detected a sleep-related change significantly quicker than GS. No other differences were observed between the two controls. These results support the notion that there is an attention bias to sleep stimuli in PI, suggesting that selective attention tasks such as the ICB may be a useful objective index of cognitive arousal in insomnia. The results also suggest that there may be an element of sleep preoccupation associated with DSPS. Results are discussed with reference to other experiments on attentional processing in insomnia.     

The impact of negative mood state on sleep‐related attentional bias in insomnia

Sleep‐related attentional bias is thought to play a role in the maintenance of insomnia. However, this concept has been questioned by several studies that did not show the presence of sleep‐related attentional bias in clinical insomnia or poor sleepers. Our goal in the present study was to test whether the mood state of individuals with insomnia affects the presence of sleep‐related attentional bias. To this end, 31 individuals with insomnia and 34 good sleepers were randomly assigned to a negative mood‐inducing condition or a control condition. They then completed a visual probe task with three types of pictorial stimuli (general threat, sleep‐related negative pictures and sleep‐related positive pictures). Vigilance, maintenance and the overall bias indexes were calculated based on the reaction time. We found individuals with insomnia only showed a greater overall bias compared with good sleepers following a negative mood induction, regardless of the pictures presented. In addition, we found that a negative mood state was significantly correlated with the overall attentional bias in good sleepers but not in individuals with insomnia. These findings suggest that sleep‐related attentional bias in insomnia can be modulated by mood state. This effect may reflect the dysregulation of top‐down attentional control in individuals with insomnia.     

Attention bias for sleep-related stimuli in primary insomnia and delayed sleep phase syndrome using the dot-probe task

STUDY OBJECTIVES: Cognitive models of primary insomnia (PI) suggest attention bias as a maintaining process. This study used a hallmark measure of attention bias, the dot-probe task, to determine whether attention bias to sleep-related stimuli is present in individuals with PI. Control groups of good sleepers (GS) and individuals with delayed sleep phase syndrome (DSPS), a sleep disorder with no presumed cognitive pathway and, hence, no predicted association with attention bias, were included. DESIGN: A between-groups (PI, DSPS, GS) design was employed. Participants completed a dot-probe task with stimuli comprising sleep-related and neutral words, balanced for length and frequency of usage. It was predicted a priori that PI would show greater attention bias to sleep stimuli compared with GS and DSPS groups. No difference between GS and DSPS was predicted. PARTICIPANTS: Sixty-three individuals completed the study (PI = 21; DSPS = 22; GS = 20), with those in PI and DSPS classified by International Classification of Sleep Disorders criteria according to self-report sleep diaries and actigraphy. GS scored < 5 on the Pittsburgh Sleep Quality Index, reported being good sleepers, and met no criteria for a current or previous sleep disorder. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: As predicted, PI showed increased vigilance for sleep-related stimuli relative to GS and DSPS. No differences between GS and those with DSPS were found. The PI group showed shorter response latencies relative to the GS and DSPS groups. CONCLUSIONS: Results support an association between attention bias and PI. Further work must determine whether or not attention bias is a causal factor. Speeded responses in the PI group suggest heightened arousal, indicating that physiologic factors may play a related role.     

Time course of attentional bias in anxiety: Emotion and gender specificity

Anxiety is characterized by cognitive biases, including attentional bias to emotional (especially threatening) stimuli. Accounts differ on the time course of attention to threat, but the literature generally confounds emotional valence and arousal and overlooks gender effects, both addressed in the present study. Nonpatients high in self‐reported anxious apprehension, anxious arousal, or neither completed an emotion‐word Stroop task during event‐related potential (ERP) recording. Hypotheses differentiated time course of preferential attention to emotional stimuli. Individuals high in anxious apprehension and anxious arousal showed distinct early ERP evidence of preferential processing of emotionally arousing stimuli along with some evidence for gender differences in processing. Healthy controls showed gender differences at both early and later processing stages. The conjunction of valence, arousal, and gender is critical in the time course of attentional bias.     

Impaired sleep-related memory consolidation in primary insomnia--a pilot study

STUDY OBJECTIVES: To compare sleep-related consolidation of procedural memory in patients with primary insomnia and healthy controls. DESIGN: Controlled comparison pilot study. SETTING: Sleep Laboratory of the Department of Psychiatry and Psychotherapy, University of Freiburg, Germany. PATIENTS OR PARTICIPANTS: Seven patients with primary insomnia and 7 sex-, age-, and IQ-matched healthy controls. INTERVENTIONS: Subjects spent 1 night in the sleep laboratory with polysomnographic monitoring. Performance on a mirror tracing task was measured before and after sleep. MEASUREMENTS AND RESULTS: Polysomnography revealed a trend toward disturbed sleep in the patients, compared with the control group, without reaching significance. Performance in the mirror tracing task before sleep did not differ between the groups. Both groups performed significantly better in the retest condition after sleep. Healthy controls showed an improvement of 42.8% +/- 5.8% in the mirror tracing draw time, whereas patients with insomnia showed an improvement of 20.4% +/- 14.8% (multivariate analyses of variance test session x group interaction: F(3,10) = 10.9, p = .002). CONCLUSIONS: These preliminary findings support the view that sleep-associated consolidation of procedural memories may be impaired in patients with primary insomnia.     

Is smoking-related attentional bias a useful marker for treatment effects?

Theoretical models of nicotine abuse suggest that preferential attention allocation towards smoking-related stimuli plays an important role in the development and maintenance of smoking behavior. However, little is known about the impact of standard treatment programs for nicotine cessation on this effect. In the current study, we investigated smoking-related attentional bias using a visual dot probe task and an emotional Stroop task before and after a standard behavioral group therapy. Smokers (n=39) who received treatment, a smoker control group without treatment (n=20) and a non-smoker control group (n=20) were investigated. Although we found a reduction in attentional bias scores after successful treatment, this effect failed to reach statistical significance. Of note, we observed a low test-retest reliability in low-dependence smokers in both tasks which is a substantial limitation for using these paradigms in longitudinal studies. Additionally, there was no significant correlation between the attentional bias scores from both tasks.     

Attentional bias for psoriasis-specific and psychosocial threat in patients with psoriasis

Information processing biases relate to the manner in which people attend to particular types of information more readily than others. This bias, which is central to cognitive models of disorder, has not been explored in patients with psoriasis. The purpose of this study was to examine whether patients with psoriasis show an automatic attentional bias to classes of information relative to controls. Sixty patients and 60 age- and sex-matched controls completed a computer-based attentional interference task (the modified Stroop task). Patients with psoriasis showed significant interference for disease-specific, self-referent, and others' behavior stimuli relative to controls. In terms of information processing biases, the relationship between subject status (psoriasis patient vs. control) and color-naming interference was significantly stronger than that between anxiety, depression and worry, and interference. Recall bias was limited to disease-specific stimuli only. The observed bias to threat is more appropriately accounted for by participant's status (i.e., psoriasis patient or control) than by psychological distress.     

An attentional inhibitory deficit for irrelevant information in obsessive-compulsive disorder: Evidence from ERPs

Previous studies on attentional bias have demonstrated that patients with obsessive–compulsive disorder (OCD) have an overall longer reaction time (RT) for various stimuli. It was hypothesized that this general slowness may indicate the presence of an attentional inhibition deficit in OCD. To test the hypothesis, event-related potentials (ERPs) were recorded in 31 non-medicated OCD patients and 29 age-, handedness- and sex-matched healthy controls while they performed an emotional Stroop task (EST). Relative to the control subjects, the OCD patients had similar interference effects for negative words, but an overall longer RT and larger P2 and P3 amplitudes to all words. These results support the notion that OCD is characterized by an attentional inhibitory dysfunction for irrelevant information.     

Neural time course of threat-related attentional bias and interference in panic and obsessive–compulsive disorders

Attentional biases to threat are considered central to anxiety disorders, however physiological evidence of their nature and time course is lacking. Event-related potentials (ERPs) characterized sensory and cognitive changes while 20 outpatients with panic disorder (PD), 20 with obsessive–compulsive disorder (OCD), and 20 healthy controls (HCs) responded to the color (emotional Stroop task) or meaning of threatening and neutral stimuli. ERPs indicated larger P1 amplitude and longer N1 latency in OCD, and shorter P1 latency in PD, to threatening (versus neutral) stimuli, across instructions to attend to, or ignore, threat content. Emotional Stroop interference correlated with phobic anxiety and was significant in PD. Participants with emotional Stroop interference had augmented P1 and P3 amplitudes to threat (versus neutral) stimuli when color-naming. The results suggest early attentional biases to threat in both disorders, with disorder-specific characteristics. ERPs supported preferential early attentional capture and cognitive elaboration hypotheses of emotional Stroop interference.     

Neural substrate of the cognitive and emotional interference processing in healthy adolescents

Emotion regulation is essential for adaptive functioning and social integration. However, it is not clear to what extent the responsible brain mechanisms are similar to those invoked in cognitive control in a non-emotional context. The aim of this study was to compare the neural circuitry of cognitive and emotional interference resolution in healthy adolescents, employing variants of the counting Stroop task. Cognitive and emotional interference processing engaged predominantly brain regions belonging to the dorsal- and the ventral attentional systems, respectively, and commonly the inferior frontal gyrus, IFG (Broca's area, left BA 45, but also right BA 45). These results suggest that BA 45 is a bridge of interaction between the dorsal- and the ventral attentional systems implicated in top-down orienting of attention and, respectively, in bottom-up processing of salient stimuli. Reaction time data showed that some participants tend to respond faster, while others respond slower to negative emotional compared to neutral trials. The emotional interference maps revealed that fast responders recruit the right temporo-parietal junction and to a larger extent the right BA 45 and the bilateral cuneus, suggesting that they engage more efficient cognitive control mechanisms to override the attentional bias. No anterior cingulate (ACC) activation was observed in either cognitive, or emotional interference; this supports the view that ACC is not involved specifically in mediating Stroop selection.     

The impact of the stimulus features and task instructions on facial processing in social anxiety: An ERP investigation

Social anxiety has been characterized by an attentional bias towards threatening faces. Electrophysiological studies have demonstrated modulations of cognitive processing from 100 ms after stimulus presentation. However, the impact of the stimulus features and task instructions on facial processing remains unclear. Event-related potentials were recorded while high and low socially anxious individuals performed an adapted Stroop paradigm that included a colour-naming task with non-emotional stimuli, an emotion-naming task (the explicit task) and a colour-naming task (the implicit task) on happy, angry and neutral faces. Whereas the impact of task factors was examined by contrasting an explicit and an implicit emotional task, the effects of perceptual changes on facial processing were explored by including upright and inverted faces. The findings showed an enhanced P1 in social anxiety during the three tasks, without a moderating effect of the type of task or stimulus. These results suggest a global modulation of attentional processing in performance situations.     

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.     

控制睡眠行为配合放松训练治疗失眠症临床观察

目的 :验证控制睡眠行为配合放松训练治疗失眠症的效果。方法 :对 44例门诊的失眠症采用控制睡眠行为配合放松训练进行治疗 ,疗程 8周。以作者自制的睡眠情况评定表来判断失眠者的睡眠效率、实际睡眠时间和失眠者的睡眠满意评分。结果 :实际睡眠时间于治疗后第 3周增加明显 (P <0 0 1) ,治疗后第 4、 6、 8周的实际睡眠时间进一步增加 ,均较治疗前 1周显著延长 (P均 <0 0 1) ,睡眠满意评分于治疗后第 4、 6、 8周睡眠较满意率与疗前 1周比增加较为明显 (P均 <0 0 1) ,睡眠较满意率从疗前一周的 2 2 7%增加到第 8周的 86 1%。 44例失眠症有 36例 ( 81 82 % )坚持治疗 8周。结论 :控制睡眠行为配合放松训练法对于治疗失眠症有显著的效果