Deficits in attention performance are associated with insufficiency of slow-wave sleep in insomnia

Nocturnal Delta Power is Associated With Lower Next-Day Pain But Not Pain Catastrophizing: Results From a Cohort of Female Participants With Temporomandibular Joint Pain

Existing data demonstrate reduced delta power during sleep in patients with depression and chronic pain. However, there has been little examination of the relationship between delta power and pain-reports, or pain-catastrophizing. We recruited female participants (n = 111) with insomnia and temporomandibular disorder, and measured nocturnal and daytime measures of pain and pain catastrophizing, and calculated relative nocturnal delta (0.5-4 Hz) power during sleep. We fit linear regression models, and further examined the moderating effect of depressive symptom severity. Lower relative delta power across the whole night was significantly associated with greater nocturnal pain (B = -20.276, P = .025, R2 = 0.214). Lower relative delta power during the first-third of the night, was associated with greater nocturnal pain (B = -17.807, p = 0.019, R2 = 0.217), next-day pain (B = 13.876, P = .039, R2 = 0.195), and next-morning pain (B = -15.751, P = .022, R2 = 0.198). Lower relative delta power during the final-third of the night was significantly associated with greater nocturnal (B = -17.602, P = .029, R2 = 0.207) and next-morning pain (3rd: B = -14.943, P = .042, R2 = 0.187). Depressive symptom severity did not moderate these relationships. Delta power was not significantly associated with nocturnal or daytime pain catastrophizing. These findings demonstrate that greater relative delta power during sleep is associated with lower nocturnal and next-day pain in patients with temporomandibular disorder. This data may guide the use of sleep interventions in clinical pain populations, with the aim of improving pain outcomes. PERSPECTIVE: This article presents data demonstrating an association between increased nocturnal delta power and reduced next-day pain. These findings may help promote interventions which aim to increase nocturnal delta power in clinical pain populations, with the goal of improving pain outcomes.

Functional connectivity correlates of attentional networks in insomnia disorder: A pilot study

Insomnia disorder has been associated with poor executive functioning. Functional imaging studies of executive functioning in insomnia are scarce and inconclusive. Because the Attentional Network Test relies on well-defined cortical networks and sensitively distinguishes different aspects of executive function, it might reveal brain functional alterations in relatively small samples of patients. The current pilot study assessed functional connectivity during the Attentional Network Test performed using magnetic resonance imaging in 12 participants with insomnia and 13 self-defined good sleepers. ANCOVAs were used to evaluate group differences in performance and functional connectivity in the regions of interest representing the attentional networks (i.e. alerting, orienting and executive control) at p < 0.05, uncorrected. During the orienting part, participants with insomnia showed weaker connectivity of the precentral gyrus with the superior parietal lobe (false discovery rate-corrected), while they showed stronger connectivity between premotor and visual regions. Individual differences in connectivity between premotor and visual regions correlated inversely with reaction time. Reaction times suggested more efficient executive control in participants with insomnia compared with good sleepers. During the executive control part, participants with insomnia showed stronger connectivity of thalamic parts of the arousal circuit with the middle frontal and the occipital gyri. Conversely, connectivity between the inferior and superior frontal gyri was weaker. Participants with insomnia seem to recruit more cortical resources in visuo-motor regions to orient attention than good sleepers do, and seem to have enhanced executive control that relates to stronger connectivity of arousal-related thalamic areas. This latter result should be treated with caution and requires confirmation.

The Short and Long-Term Effect of Sound Therapy on Visual Attention in Chronic Tinnitus Patients

Sound therapy is one of the most common tinnitus treatments that can be used either to mask or to shift attention away from the tinnitus percept. However, the actual benefit of sound therapy and the mechanisms leading to the benefits remain limited. The objective of this study was to investigate the short-term (15 min) and long-term (2 months) effects of sound therapy on visual attention in chronic tinnitus patients. Visual attention was evaluated with the behavioral Attention Network Task, while the tinnitus-related distress was evaluated with the Tinnitus Handicap Inventory (THI) to quantify the effect of sound therapy. The study included 20 participants with chronic and bothersome tinnitus (>6 months, THI > 18) and 20 matched control participants. All participants took part in a first session consisting of a baseline condition, a short-term sound therapy condition and a silent control condition. The tinnitus participants also took part in a second session that evaluated the long-term effect of the therapy. A reduction in the tinnitus-related distress was found after the long-term use of sound therapy. Furthermore, a reduction in the differential index of the executive control (EC) attention network, indicating improved attention, was found after long-term use of sound therapy in the sound condition but not in the silent control condition. In contrast to earlier research, no differences were found between the tinnitus group and the control group for the baseline measurement of the EC attention network. Overall, the results suggest that there is no link between the visual attention networks and the sound therapy’s effect on tinnitus-related distress.

The associations of insomnia symptoms with daytime behavior and cognitive functioning in children with attention-deficit/hyperactivity disorder

STUDY OBJECTIVES

The current study aimed to examine the association of insomnia symptoms with daytime behavior and cognitive functioning in children with attention-deficit/hyperactivity disorder (ADHD).

METHODS

Thirty-six children with ADHD and insomnia symptoms, 27 children with ADHD without insomnia symptoms, and 21 age-matched healthy controls were recruited in this study (age range: 6-12 years, 70% male). They were assessed by parent-report questionnaires on insomnia symptoms (Children's Sleep Habits Questionnaire) and ADHD symptoms (Strengths and Weaknesses of ADHD Symptoms and Normal Behavior Scale [SWAN]), and completed a battery of cognitive tests including the Continuous Performance Test (CPT) for sustained attention, Letter-digit test for processing speed, Digit Span forward test and N-back task for working memory, Tower of London (TOL) test for planning skills and Bergs Card Sorting Test (BCST) for set-shifting ability.

RESULTS

Children with ADHD and insomnia symptoms had the highest scores on SWAN total and inattention and hyperactivity subscales, followed by children with ADHD without insomnia and healthy controls (all P < .05). After controlling for potential confounders, children with ADHD and insomnia symptoms showed poorer performance on the CPT and Letter-digit test as compared with children with ADHD without insomnia and healthy controls (all P < .05).

CONCLUSIONS

Insomnia symptoms are associated with more severe ADHD symptoms and cognitive impairments in children with ADHD, especially deficits in sustained attention and processing speed. Future longitudinal studies are needed to explore the long-term impacts of insomnia symptoms and the effects of sleep-focused intervention on cognitive functioning in children with ADHD.

CITATION

Li X, Shea KSC, Chiu WV, et al. The associations of insomnia symptoms with daytime behavior and cognitive functioning in children with attention-deficit/hyperactivity disorder. J Clin Sleep Med. 2022;18(8):2029-2039.

Paradoxical relationship between subjective and objective cognition: the role of sleep

STUDY OBJECTIVES

Subjective memory complaints and objective cognitive dysfunction are common in aging populations, however research investigating the associations between them is inconclusive. Given the high prevalence of sleep complaints in middle-aged/older adults, this research tested whether objective cognition interacted with sleep parameters in its associations with subjective cognition.

METHODS

Cognitively healthy adults aged 50+ completed the Pittsburgh Sleep Quality Index, Cognitive Failures Questionnaire (CFQ) and cognitive tasks: Stroop, Sternberg, and Posner cueing. Multiple regression and simple slope analyses examined whether objective cognition interacted with sleep parameters in its associations with subjective memory.

RESULTS

Stroop performance and sleep (efficiency and disturbances) had interactive associations with CFQ-memory. Specifically, better Stroop performance (faster reaction time, RT-control trials) was associated with more memory complaints at worst and average, but not best sleep efficiency. Additionally, faster RT was associated with more memory complaints only for worst sleep disturbance. Similarly, Sternberg performance and sleep (efficiency and disturbances) had interactive associations with CFQ-memory. Specifically, higher proportion correct was associated with more memory complaints only at worst sleep efficiency and sleep disturbance. Finally, Posner performance and sleep disturbance had an interactive association with CFQ-memory. Faster exogenous orienting was associated with more memory complaints only for worst sleep disturbance.

CONCLUSIONS

Objective cognition interacts with sleep efficiency and sleep disturbances in its associations with subjective memory in mid-to-late life. Findings suggest sleep fragmentation plays a role in the discrepant relationship between objective and subjective cognition. Future studies should investigate this relationship in aging populations with sleep disorders and/or cognitive impairments.

Lessons unlearned: A conceptual review and meta-analysis of the relationship between the Attention Control Scale and Objective Attention Control

Attention control is central to many models of emotion. Among the most common measures of attention, control is the Attention Control Scale (ACS), which has exerted considerable influence in terms of the volume and breadth of research findings, with its use in cognitive-experimental research continuing to increase in recent years. However, there are growing concerns about whether the ACS genuinely indexes attention control. The present paper considers the context and development of the ACS, reviews and meta-analyses the available evidence regarding its association with objective measures of attention control. Meta-analytic results from nine studies (total n = 1274) indicated that the full-scale ACS was not significantly associated with behavioural measures of attentional control (r = .067, p = .093, N = 1274, 95% CI: -.011, .145). Findings indicated likely missing studies with lower correlations suggesting the true association may be smaller. Limited evidence of shared variance between subjective and objective measures of attention control contrasts with considerable evidence that the scale is closely correlated with dispositional traits (e.g. anxiety, agreeableness) that could plausibly influence responding. Thus, on the balance of current findings, we conclude that there is little compelling evidence that responding on the ACS reflects genuine attention control abilities.

Comparison of the effect of lemborexant with placebo and zolpidem tartrate extended release on sleep architecture in older adults with insomnia disorder

STUDY OBJECTIVES

Changes to sleep architecture that occur as a result of the normal aging process may also exacerbate insomnia in older individuals. Therefore, this study assessed the impact of lemborexant compared with placebo and zolpidem tartrate extended release on objective sleep architecture parameters, as measured by polysomnography, in older adults (ages ≥ 55 years) with insomnia disorder from a phase 3 study.

METHODS

Study E2006-G000-304 (SUNRISE 1; NCT02783729) was a global, multicenter, randomized, double-blind, placebo-controlled, active comparator (zolpidem)-controlled, parallel-group study comparing 2 dose levels of lemborexant (5 mg and 10 mg). Sleep architecture was measured using polysomnography. Assessments were collected at baseline during a single-blind placebo run-in and during the first 2 nights and last 2 nights of treatment. Mean values for each sleep stage were based on the 2 consecutive polysomnograms.

RESULTS

Treatment with lemborexant resulted in significantly greater increases from baseline in total sleep time compared with both placebo and zolpidem. Significant increases from baseline in rapid eye movement sleep and significant decreases from baseline in latency to rapid eye movement sleep were also observed with lemborexant compared with placebo and zolpidem.

CONCLUSIONS

These findings suggest that treatment with lemborexant may address some of the alterations in sleep architecture normally observed in older individuals with insomnia.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Study of the Efficacy and Safety of Lemborexant in Subjects 55 Years and Older With Insomnia Disorder (SUNRISE 1); URL: https://clinicaltrials.gov/ct2/show/NCT02783729; Identifier: NCT02783729.

Insomnia, Inattention and Fatigue Symptoms of Women with Premenstrual Dysphoric Disorder

Aim: Premenstrual dysphoric disorder (PMDD) has predictable, cyclic, psychological, and somatic symptoms, such as sleep problems. They result in functional impairment, are aggravated in the late luteal phase of the menstrual cycle, and are resolved by menstruation. The present study evaluated the insomnia, inattention, and fatigue symptoms of PMDD and their fluctuations during the menstrual cycle. Methods: A total of 100 women were diagnosed as having PMDD based on psychiatric interviews and a prospective investigation of three menstrual cycles. A total of 96 individuals without PMDD were recruited as controls. Their symptoms, namely insomnia, inattention, and fatigue as well as functional impairment were assessed by using the premenstrual symptoms screening tool, the Pittsburgh insomnia rating scale, the attention and performance self-assessment scale, and the fatigue-assessment scale during both premenstrual and follicular phases. Results: In both the premenstrual and follicular phases, women with PMDD experienced more severe insomnia, inattentiveness, and fatigue than did women in the control group. A paired t-test demonstrated that women with PMDD had more severe severity insomnia, inattentiveness, and fatigue in the luteal phase than in the follicular phase. A repeated-measures analysis of variance demonstrated that the interaction period of PMDD and a menstrual cycle was significantly associated with insomnia, inattentiveness, and fatigue. A further correlation analysis demonstrated that all three symptoms were positively associated with self-reported functional impairment due to PMDD. Conclusions: Our results demonstrated that women with PMDD experienced an exacerbation of insomnia, memory problems, difficulty maintaining focus, and fatigue in the premenstrual phase. These symptoms are correlated with PMDD symptoms severity and functional impairment, and as such, they should be evaluated, and interventions should be employed in the late luteal phase of women with PMDD.

Cognitive deficit is correlated with sleep stability in insomnia: A cardiopulmonary coupling study

OBJECTIVES

To assess the correlation of cognitive function with sleep stability and depressive-anxious symptoms in insomnia patients.

METHODS

Twenty-two insomnia patients with cognitive impairment (insomnia-CI), 21 insomnia patients with normal cognition (insomnia-CN), and 15 matched healthy control subjects (HCs) were enrolled and completed neuropsychological tests, the Hamilton Depression and Anxiety Scales (HAMD and HAMA), the Epworth Sleepiness Scale, the Pittsburgh Sleep Quality Index (PSQI),the Insomnia Severity Index (ISI), and the cardiopulmonary coupling (CPC) examination. Ratios of high-frequency coupling (HFC), low-frequency coupling (LFC), and very low-frequency coupling (VLFC) measured by CPC analysis represent stable sleep, unstable sleep, and wake/rapid eye movement (REM) sleep, respectively.

RESULTS

The HAMD, HAMA, PSQI, and ISI scores were higher in the insomnia-CN patients than in the HCs (all p < .01). However, no differences were found in the HFC, LFC, and VLFC ratio between the HCs and insomnia-CN groups. Compared with the insomnia-CN patients, insomnia-CI patients exhibited higher scores on the HAMD, HAMA (all p < .01), and PSQI (p < .05), performed worse on the Auditory Verbal Learning Test, Trial Making Test B, and Stroop Test B (all p < .01), had a lower HFC ratio, and had a higher LFC ratio in the CPC analysis (all p < .01). Furthermore, in the insomnia patients, poorer cognition was correlated with a decreased HFC ratio and an increased VLFC ratio (r = .356, p = .019; r = -.339, p =.026, respectively) and increased HAMD and HAMA scores (r = -.507, p < .001; r = -.561, p < .001, respectively); a higher VLFC ratio was correlated with an increased ISI score (r = .346, p = .023).

CONCLUSIONS

Cognitive deterioration in insomnia patients was associated with a decreased stable sleep ratio, an increased wake/REM sleep ratio and more severe symptoms of depression and anxiety. CPC analysis can reflect the severity of insomnia.

Systematic decrease of slow-wave sleep after a guided imagery designed to deepen sleep in low hypnotizable subjects

Slow-wave sleep is one of the most important restorative components of sleep and central for our health and cognitive functioning. Although the amount of slow-wave sleep depends on sleep drive, age and other factors, also the pre-sleep mental state might influence sleep depth. We had shown that a pre-sleep hypnotic suggestion to sleep more deeply increased slow-wave sleep duration in hypnotizable subjects. In contrast, low-hypnotizable participants decreased sleep depth after this intervention. A possible reason might be an aversion to and active resistance against hypnosis. To overcome this potential opposition, we introduced the procedure as 'guided imagery'. We replaced the hypnotic induction by a breathing relaxation. Importantly, the suggestion 'to sleep more deeply' remained identical. We expected that these changes would make it easier for low-hypnotizable subjects to benefit from the suggestion. In contrast, young healthy low-hypnotizable participants did not show positive effects. Similar to our previous studies, they exhibited a reduced slow-wave sleep duration after the intervention. Additionally, the ratio between slow-wave activity and beta band power decreased. Subjective sleep quality remained unaffected. Our results indicate that suggestions to sleep more deeply result in decreased sleep depth in low-hypnotizable participants regardless of the mental technique (guided imagery versus hypnosis). Thus, the aversion against hypnosis per se cannot explain the detrimental effect of the intervention on slow-wave sleep in low-hypnotizable subjects. The results support the notion that our mental state before sleep can influence subsequent slow-wave sleep. However, the mechanisms of the contradictory decrease in low-hypnotizable subjects remain unknown.

Effect of magnetic stimulation of Shenmen point on cognitive function of chronic insomnia: A randomized controlled clinical trial

BACKGROUND

Chronic insomnia (CI) can lead to cognitive dysfunction and bring great pain to patients' life. There is no effective intervention for cognitive dysfunction caused by CI. Shenmen (HT7) is the first choice for insomnia treatment. However, the effect and mechanism of this acupoint on cognitive function after insomnia is not clear. Therefore, the purpose of this study is to explore whether magnetic stimulation of HT7 can improve cognitive impairment of CI by regulating prefrontal lobe and its mechanism.

METHODS/DESIGN

This is a randomized controlled clinical trial. Seventy-two subjects aged 18 to 65 years old with primary insomnia and more than 3 months were randomly divided into 2 groups according to the ratio of 1:1, and 36 healthy controls were included. The control group was given sleep hygiene and cognitive therapy in behavioral cognitive therapy technology, while the experimental group was given the behavioral cognitive therapy technology intervention and magnetic stimulation of HT7 acupoint for 30 times (2 times / d, 5 times / wk for 20 days), while the healthy control group had no intervention measures. Before treatment and 20 days after treatment, we evaluated the working memory (1-back test), episodic memory (Complex Figure Test), and problem-solving ability (Hanoi tower test) processed by prefrontal lobe to explore the effect of magnetic stimulation on cognitive function of CI and its possible mechanism. At the same time, insomnia severity index was used to evaluate sleep state, Becker depression scale was used to evaluate depression, and Beck anxiety scale was used to evaluate anxiety. Chi-squared test or rank sum test was used to collect the data of patients. If P value is less than or equal to .05, the difference will be considered statistically significant.

CONCLUSION

This study explored the effect and mechanism of magnetic stimulation of Shenmen (HT7) on cognitive function of CI, and confirmed that magnetic stimulation of HT7 can be used as an alternative therapy to improve cognitive impairment of CI.

TRIAL REGISTRATION NUMBER

ChiCTR2000034280.

Characteristics of Sleep Structure Assessed by Objective Measurements in Patients With Amnestic Mild Cognitive Impairment: A Meta-Analysis

Objectives: This study aims to explore the differences of sleep structure between patients with amnestic mild cognitive impairment (aMCI) and elderly people with normal cognition, which will help to provide evidence for the relationship between sleep disturbances and cognitive impairment.

Methods: A systematic review and meta-analysis were conducted on the literature on sleep parameters obtained by polysomnography or actigraphy in patients with aMCI. The PubMed and EMBASE databases were searched up to April 2020. Inclusion and exclusion criteria were established according to evidence-based medicine methods, and data of all eligible studies were meta-analyzed using the Review Manager 5.3 software.

Results: Among the 1,171 literature articles on sleep structure of patients with MCI, eight case-control studies met the inclusion criteria and were included in this meta-analysis. A total of 278 subjects were included, of which 103 were patients with aMCI and 175 were elderly people with normal cognition. The results showed that sleep efficiency (SE) and slow wave sleep (SWS) of patients with aMCI were significantly lower than those of healthy elderly people. Compared with the control group, the percentage of stage 1 of non-rapid eye movement (N1%) in the aMCI patients group increased, and the percentage of stage 2 of non-rapid eye movement (N2%) decreased.

Conclusions: Patients with aMCI may experience more severe sleep disturbances than normal cognitive elderly people. There were specific changes, especially in SE and SWS, in the sleep structure of patients with aMCI when compared to those with normal cognition.

Effect of Sleep Disorder on Delirium in Post-Cardiac Surgery Patients

BACKGROUND

Post-cardiac surgery patients exhibit a higher incidence of postoperative delirium (PD) compared to non-cardiac surgery patients. Patients with various cardiac diseases suffer from preoperative sleep disorder (SPD) induced by anxiety, depression, breathing disorder, or other factors.

OBJECTIVE

To examine the effect of sleep disorder on delirium in post-cardiac surgery patients.

METHODS

We prospectively selected 186 patients undergoing selective cardiac valve surgery. Preoperative sleep quality and cognitive function of all eligible participants were assessed through the Pittsburgh Sleep Quality Index (PSQI) and the Montreal Cognitive Assessment, respectively. The Confusion Assessment Method for Intensive Care Unit was used to assess PD from the first to seventh day postoperatively. Patients were divided into two groups according to the PD diagnosis: (1) No PD group and (2) the PD group.

RESULTS

Of 186 eligible patients, 29 (15.6%) were diagnosed with PD. A univariate analysis showed that gender (p = 0.040), age (p = 0.009), SPD (p = 0.008), intraoperative infusion volume (p = 0.034), postoperative intubation time (p = 0.001), and intensive care unit stay time (p = 0.009) were associated with PD. A multivariate logistic regression analysis demonstrated that age (odds ratio (OR): 1.106; p = 0.001) and SPD (OR: 3.223; p = 0.047) were independently associated with PD. A receiver operating characteristic curve demonstrated that preoperative PSQI was predictive of PD (area under curve: 0.706; 95% confidence interval: 0.595-0.816). A binomial logistic regression analysis showed that there was a significant association between preoperative 6 and 21 PSQI scores and PD incidence (p = 0.009).

CONCLUSIONS

Preoperative SPD was significantly associated with PD and a main predictor of PD.

Hyperarousal Is Associated with Socioemotional Processing in Individuals with Insomnia Symptoms and Good Sleepers

Despite complaints of difficulties in waking socioemotional functioning by individuals with insomnia, only a few studies have investigated emotion processing performance in this group. Additionally, the role of sleep in socioemotional processing has not been investigated extensively nor using quantitative measures of sleep. Individuals with insomnia symptoms (n = 14) and healthy good sleepers (n = 15) completed two nights of at-home polysomnography, followed by an afternoon of in-lab performance testing on tasks measuring the processing of emotional facial expressions. The insomnia group self-reported less total sleep time, but no other group differences in sleep or task performance were observed. Greater beta EEG power throughout the night was associated with higher intensity ratings of happy, fearful and sad faces for individuals with insomnia, yet blunted sensitivity and lower accuracy for good sleepers. Thus, the presence of hyperarousal differentially impacted socioemotional processing of faces in individuals with insomnia symptoms and good sleepers.

Connections Between Insomnia and Cognitive Aging

Insomnia is a common sleep disorder among older adults, and a risk factor for poor physical and mental health. However, the relationship between insomnia and cognitive health is not well understood. Here, we review observational studies that have investigated whether insomnia is associated with deficits in objective cognitive performance and an increased risk of dementia, magnetic resonance imaging studies that have assessed grey matter volumes and white matter microstructure, and interventional studies that have explored whether the treatment of insomnia can improve cognitive outcomes. There are inconsistent findings regarding impaired performance in objective cognitive tests and reduced grey matter volumes, and limited, emerging, evidence that suggests that insomnia is associated with an increased risk of dementia and reduced white matter integrity. Although the interventional literature is still in its infancy, there is some indication that treatment may have an impact on vigilance. Well-powered studies examining sources of heterogeneity are warranted.

Impaired emotional memory and decision-making following primary insomnia

Previous studies have indicated that sleep plays an important role in emotional memory and decision-making. However, very little attention has been given to emotional memory and decision-making in patients with primary insomnia (PI). We investigated whether PI influences the accuracy of emotional memory and social decision-making.We examined 25 patients with PI and 20 healthy controls (HC) using an emotional picture memory task and the Iowa Gambling Task (IGT). In the emotional picture memory task, participants completed two testing sessions: an emotional picture evaluation and a delayed recognition phase. During the emotional picture evaluation phase, participants were presented with 48 pictures with different valence (16 positive, 16 neutral, and 16 negative), which they had to evaluate for emotional valence and arousal. During the recognition phase, participants were asked to make a yes/no memory assessment of a set of pictures, which contained the 48 target pictures intermingled with 48 non-target pictures.The performance of the participants with PI was the same as that of the HC in the emotional picture evaluation task. However, the PI group showed worse recognition of the positive and neutral pictures than did the HC group, although recognition of negative pictures was similar in the 2 groups. In the IGT, participants in the PI group more frequently selected cards from the risky decks as the game progressed and selected more disadvantageous cards than did participants in the HC group after the first block.Our findings suggest that insomnia had different effects on memory, depending on the valence of the memory. Specifically, memory performance was impaired for positive and neutral items, but the recognition of negative stimuli seemed to be more resistant to the effects of insomnia. Our results also suggest that decision-making, which is known to be mediated by the ventromedial prefrontal cortex, including decision-making under conditions of uncertainty, may be vulnerable in PI.

Tired and lack focus? Insomnia increases distractibility

Chronic insomnia is associated with subjective daytime cognitive dysfunction, but objective corroborative data are often lacking. In this study, we use Perceptual Load Theory to objectively assess distractibility in participants with insomnia ( N = 23) compared with age- and sex-matched controls ( N = 23). Following overnight supervised sleep observation, all participants completed a selective attention task which varied in the level of perceptual load and distractor congruency. The insomnia group was found to be more distracted than controls, whereas their selective attention mechanism appeared to be intact, with reduced distractor processing under high load for both groups. Insomnia symptom severity was positively correlated with participant distractibility. These findings suggest that there are insomnia-related daytime cognitive impairments that are likely to arise from compromised cognitive control rather than an ineffective selective attention mechanism. This task may be clinically useful in assessing daytime impairments, and potentially treatment response, in those with insomnia.

Altered Regional Homogeneity in Chronic Insomnia Disorder with or without Cognitive Impairment

BACKGROUND AND PURPOSE

Many studies have shown that insomnia is an independent factor in cognitive impairment, but the involved neurobiological mechanisms remain unclear. We used regional homogeneity to explore the specific neurobiologic indicators of chronic insomnia disorder with mild cognitive impairment.

MATERIALS AND METHODS

Thirty-nine patients with insomnia were divided into a group with and without cognitive impairment; we also included a control group (n = 28). Abnormalities in brain functional activity were identified by comparing the regional homogeneity values for each brain region among the groups.

RESULTS

Subjective insomnia scores were negatively correlated with cognitive impairment after controlling for age, sex, and educational effects. Regions with significant differences in regional homogeneity values in the 3 groups were concentrated in the right medial prefrontal cortex, the right superior frontal gyrus, and the left superior occipital gyrus. Meanwhile, subjective insomnia scores were negatively correlated with the strength of the decreased regional homogeneity in the right medial prefrontal cortex. The increased regional homogeneity value in the right superior frontal gyrus was positively correlated with the Montreal Cognitive Assessment score in patients.

CONCLUSIONS

Our results indicate that decreased regional homogeneity values in the medial prefrontal cortex and increased regional homogeneity values in the cuneus may be important neurobiologic indicators of chronic insomnia disorder and accompanying cognitive impairment. Overall, our study described the regional homogeneity of the whole brain in chronic insomnia disorder with mild cognitive impairment and could be the basis for future studies.

Patients with chronic insomnia disorder have increased serum levels of neurofilaments, neuron-specific enolase and S100B: does organic brain damage exist?

OBJECTIVES

The aims of this study were to investigate whether serum levels of neurofilaments heavy chain (NfH) and light chain (NfL), neuron-specific enolase (NSE) and S100 calcium binding protein B (S100B): (1) change, (2) alleviate in post-therapy and (3) are associated with sleep quality and cognitive dysfunction, in patients with chronic insomnia disorder (CID).

METHODS

Forty CID outpatients constituted free-therapy group (ft-CID), in which twenty-four patients completed follow-up after six-month treatment to form re-visiting group (rv-CID), and twenty healthy good sleepers constituted control group (HC). All subjects completed questionnaires, polysomnography, Chinese-Beijing Version of Montreal Cognitive Assessment (MoCA-C) and Nine Box Maze Test (NBMT) to assess sleep and neuropsychological function. The serum levels of NfH, NfL, NSE and S100B were detected using enzyme-linked immunosorbent assay.

RESULTS

The ft-CID had higher levels of NfH, NfL, NSE and S100B than the HC. Of note, the levels of NfH, NfL and NSE were significantly reduced in the rv-CID compared to the ft-CID, but not the level of S100B. Principal components analysis revealed that in these serum biomarkers, NfL and S100B had a substantial correlation with subjective and objective sleep parameters.

CONCLUSIONS

The CID patients had elevated serum levels of NfH, NfL, NSE and S100B, indicating existence of damaged brain microstructure, including neurons, astrocytes and neuronal terminals, which were associated with the insomniac severity or/and cognitive dysfunction and could significantly reduce after effective therapy apart from the S100B.

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.