Examination of daytime sleepiness and cognitive performance testing in patients with primary insomnia

Challenging subjective excessive daytime sleepiness as an insomnia symptom: a retrospective study

Diagnostic manuals describe insomnia disorder (ID) characterised by fatigue and sleepiness as diurnal consequences of nocturnal symptoms. However, patients with ID do not frequently report sleepiness in the clinical setting. The present study aimed to investigate subjective sleepiness in ID measured through the Epworth Sleepiness Scale (ESS) and its independence towards daytime functioning and fatigue, and to evaluate cognitive behavioural therapy for insomnia (CBT-I) improvement in daytime consequences and their relationship to sleepiness and fatigue. We retrospectively collected the ESS evaluation in a large sample of 105 healthy controls (HCs), 671 patients with ID, and 602 patients with sleep disorders characterised by excessive daytime sleepiness (EDS). Moreover, we conducted a pre-post evaluation of the ESS in a sub-sample of patients with ID who underwent CBT-I. Component 2 of the Insomnia Severity Index and Profile of Mood States-Fatigue Inertia Scale was used to evaluate daytime functioning and fatigue. Patients with ID reported ESS levels comparable to that observed in HCs and significantly lower than the EDS group. No significant correlation arose between ESS and the diurnal impact of the disorder, suggesting the independence between daytime functioning and sleepiness in ID. Contrarily, insomnia severity and diurnal impact significantly correlated with fatigue. Data showed a statistically significant increase in sleepiness after CBT-I, despite significantly improving daytime consequences and fatigue. Although diagnostic manuals report sleepiness and fatigue as daytime consequences of sleep symptoms in patients with ID, these retrospective data indicate a dissociation between these entities. This evidence aligns with the core feature of ID: the hyperarousal status that pervades patients also during wakefulness.

Daytime sleepiness in insomnia: Are we focusing on what truly matters?

Insomnia, the most prevalent sleep disorder, is commonly associated with other mental and somatic disorders, making it a significant health concern. It is characterized by nighttime symptoms and daytime dysfunction, with sleepiness being a potential criterion for the latter. Sleepiness is a normal physiological state that is typically experienced near usual bedtime, in normal circumstances. In insomnia, it seems somewhat logical the idea that there is significant daytime sleepiness. However, the topic has been the subject of various discussions in sleep medicine, with studies yielding contradictory and inconsistent results. In this article, we aim to critically examine daytime sleepiness in individuals with insomnia disorder and propose an alternative approach to addressing it, both in clinical practice and research settings. It is crucial to further investigate the role of daytime sleepiness in insomnia, particularly by focusing on sleepiness perception as a more relevant dimension to explore in majority of patients. It is plausible that certain insomnia phenotypes are objectively sleepy during the day, but more studies are necessary, particularly with well-defined clinical samples. The implications of assessing sleepiness perception in insomnia for clinical practice are discussed, and new avenues for research are suggested.

Doxepin is more effective than zolpidem in improving executive function in patients with insomnia disorder

BACKGROUND : Insomnia disorder is associated with an impairment in cognitive performance. Doxepin and zolpidem have been found to be effective in improving sleep. In this study, we aimed to compare the effects of doxepin and zolpidem on sleep structure and executive function in patients with insomnia disorder.

METHODS

Patients with primary insomnia were randomly assigned to receive doxepin 6 mg/day orally or zolpidem 5-10 mg/day orally. Polysomnography (PSG) and the Pittsburgh Sleep Quality Index (PSQI) were used at baseline and after the 8-week treatment to compare clinical efficacy in the two groups. Safety was assessed using the Treatment Emergent Symptom Scale (TESS). Executive function was evaluated using the Wisconsin sorting card test (WSCT).

RESULTS

Of 120 patients enrolled in the study, 60 participants were assigned to each group. A total of 109 participants (53 in the doxepin group and 56 in the zolpidem group) completed the study. After treatment, the wake after sleep onset (WASO) and total sleep time (TST) values in the doxepin group were 80.3 ± 21.4 min and 378.9 ± 21.9 min, respectively, which were significantly better than those in the zolpidem group (132.9 ± 26.5 min and 333.2 ± 24.2 min, respectively; (P < 0.05)). The sleep onset latency (SOL) value in the zolpidem group (20.3 ± 4.7 min) was significantly better than that in the doxepin group (28.2 ± 5.6 min; P < 0.05). The sleep efficiency (SE) in the doxepin group was 77.8 ± 4.2%, which was significantly better than that in the zolpidem group (68.6 ± 5.0%; P < 0.05). The PSQI score of the doxepin group was 6.1 ± 1.1, which was significantly lower than that in the zolpidem group (7.9 ± 1.9; P < 0.05). The treatment adverse events in the doxepin group was 23.3%, which was significantly higher than that in the zolpidem group (13.3%; P < 0.05). The WSCT showed a significant improvement in persistent errors (PE), random errors (RE), and categories in the two groups after 8-week treatment, and the improvement in RE and the categories was more obvious in the doxepin group (P < 0.05).

CONCLUSIONS

Both doxepin and zolpidem were found to be effective in improving sleep quality, but the effects exhibited different patterns. Doxepin improved executive function more effectively than zolpidem in patients with insomnia disorder.

Disruptions in self-regulatory processes predict depression and sleep disturbance in bereaved young adults

Losing a loved one is both common and profoundly stressful for young adults. Little research has examined the longitudinal course of post-loss cognitive processing, depression, and sleep difficulties. Further, little is known about the context of other stressors or the role of individual regulatory resources, such as attentional regulation, that might determine whether loss-related cognitive processing reduces distress. This prospective study examined changes in depression and sleep disturbance over 9 weeks as a function of within- and between-person variation in stress exposure, loss-related cognitive processing, and attention regulation. Participants were 108 recently bereaved college students completing a lab-based assessment of attention regulation and four self-report surveys, spaced three weeks apart. Results revealed that most participants gradually reduced loss-related processing over the study period, with corresponding improvements in depression and sleep. Stress exposure was associated with increased processing, depression, and sleep disturbance. In exploratory analyses, high attentional alertness and slow re-orienting strengthened the association of within-person loss processing with sleep disturbance. Both within- and between-person variation in stress appear to engender risk for a prolonged course of bereavement. Future research should integrate objective attention measures with self-reported adjustment to stress to illuminate reciprocal links between depression, sleep, and loss-related cognitive processing.

The role of the left dorsolateral prefrontal cortex in conflict control during insomnia disorder

BACKGROUND

Patients with insomnia are often accompanied by cognitive dysfunction, which seriously affects the quality of life of patients. Repetitive transcranial magnetic stimulation (rTMS) can induce brain neuroplasticity, regulate brain cognitive function and inhibitory control ability.

OBJECTIVE

To explore the intervention effect of rTMS on conflict control and sleep quality in patients with insomnia.

METHODS

In this single-blind, randomized controlled trial, 39 people with insomnia disorder were randomly divided into real stimulation group and sham stimulation group. The stimulation parameters were stimulation frequency 1 Hz, stimulation intensity 80 % resting motor threshold (RMT), total pulse number 1500 times, time 25 min, and the whole course of treatment lasted 7 days. The Insomnia Severity Index(ISI)、Pittsburgh Sleep Quality Index(PSQI)、Multidimensional Fatigue Inventory(MFI) and Beck Anxiety Inventory(BAI) were assessed at pretest (baseline) and posttest (day 7 after intervention), and the color-word stroop task was used to measure the conflict control ability of the subjects.

RESULTS

The sleep quality, correct rate and reaction time of the posttest in the real stimulus group were higher than those in the pretest. However, there was no significant difference between the pretest and posttest in the sham stimulation group.

CONCLUSIONS

rTMS stimulation of the left dorsolateral prefrontal cortex (LDLPFC) in patients with insomnia can significantly improve the conflict control ability and sleep quality of patients with insomnia.

Nighttime sleep quality & daytime sleepiness across inpatient psychiatric treatment is associated with clinical outcomes

Prior research has demonstrated the strong link between sleep disturbance and mental health outcomes, including the importance of examining nighttime sleep quality and daytime sleepiness as separate constructs in relation to mental health outcomes. As such, the current study examined patients' self-reported nighttime sleep quality and daytime sleepiness trajectories over the course of inpatient treatment and how these trajectories related to treatment outcomes. Participants were 1,500 adults who voluntarily admitted to an inpatient psychiatric hospital. Mental health outcomes measured were emotion regulation problems, anxiety severity, depression severity, nightmare severity, and suicide risk. Group-based trajectory modeling was used to determine nighttime sleep quality and daytime sleepiness trajectory groups. Multivariate analyses of covariance (MANCOVA) were used to determine between group differences on mental health outcomes. Patients fit into distinct groups based on their trajectories of nighttime sleep quality and daytime sleepiness across inpatient psychiatric treatment: Low, Moderate, and High. Individuals with greater nighttime sleep disturbance and greater daytime sleepiness throughout treatment (High group) demonstrated significantly increased suicide risk, higher nightmare severity, more anxiety, more depression, and more emotion regulation difficulties at discharge. Results suggest an important connection exists between nighttime sleep quality and excessive daytime sleepiness and mental health outcomes for inpatient psychiatry.

Nighttime Sleep Quality and Daytime Sleepiness Predicts Suicide Risk in Adults Admitted to an Inpatient Psychiatric Hospital

As sleep problems have been identified as an important, yet understudied, predictor of suicide risk, the present study analyzed the relationship between daytime sleepiness and nighttime sleep disturbance in a high-risk population of adults admitted to an inpatient psychiatric hospital. Objectives were to (1) examine the time course of subjective daytime sleepiness, nighttime sleep disturbance, and suicide risk throughout inpatient psychiatric treatment, (2) examine pre- to post-treatment changes in sleep disturbance with treatment as usual in an inpatient psychiatric setting, and (3) investigate whether daytime sleepiness and nighttime sleep disturbance predicted suicide risk above and beyond anxiety and depression. Participants were 500 consecutively admitted adults admitted to an intermediate length of stay (4-6 weeks) inpatient psychiatric hospital (47% female; 18-87 years of age). Measures of sleep, suicide risk, depression, and anxiety were completed at admission, weeks 1 through 4, and at discharge. Latent growth curve modeling (LGM) and hierarchal linear modeling (HLM) were conducted. The LGM analysis demonstrated that daytime sleepiness, nighttime sleep disturbance, and suicide risk all improved throughout inpatient treatment. Further, HLM showed that daytime sleepiness predicted suicide risk above and beyond symptoms of anxiety, depression, major sleep medications, and prior suicidal ideation and attempts, while nighttime sleep disturbance predicted suicide risk above and beyond symptoms of anxiety, major sleep medications, and prior suicidal ideation and attempts. Findings indicate the need to reevaluate safety protocols that may impact sleep, particularly that may increase daytime sleepiness, and to develop evidence-based sleep interventions for individuals admitted to inpatient psychiatric hospitals.

Sex differences in the effects of sleep disorders on cognitive dysfunction

Sleep is an essential physiological function that sustains human life. Sleep disorders involve problems with the quality, duration, and abnormal behaviour of sleep. Insomnia is the most common sleep disorder, followed by sleep-disordered breathing (SDB). Sleep disorders often occur along with medical conditions or other mental health conditions. Of particular interest to researchers is the role of sleep disorders in cognitive dysfunction. Sleep disorder is a risk factor for cognitive dysfunction, yet the exact pathogenesis is still far from agreement. Little is known about how sex differences influence the changes in cognitive functions caused by sleep disorders. This narrative review examines how sleep disorders might affect cognitive impairment, and then explores the sex-specific consequences of sleep disorders as a risk factor for dementia and the potential underlying mechanisms. Some insights on the direction of further research are also presented.

Insomnia attenuates response inhibition: Evidence from Go/NoGo research

OBJECTIVE

Varied cognitive dysfunctions including memory, attention, inputs, processing and filtration have been found in insomnia. Meanwhile, evidence from functional neuroimaging have revealed that the abnormal metabolism in prefrontal cortex was associated with probable deficit of executive function. And in our study, we have detected the response inhibition in insomnia patients by Go/NoGo,an Event-related potentials (ERPs) study, in order to explore the impaired executive function, because response inhibition is a hallmark of executive function.

METHODS

We used polysomnography (PSG) to record such objective PSG parameters. Go/NoGo was performed in sequence, different ERP components have been analyzed such as latency or amplitude between insomnia group and control group. And we used Person correlation coefficient R to make analysis between different ERP components and gender, duration, education, BMI and sleep characteristics.

RESULTS

On the behavioral level, we found a little poor performance insomnia participants. On the electrophysiological level, under Go condition, insomnia participants have prolonged latency and smaller amplitude of N2 or P3. While, under NoGo condition, insomnia participants also have longer latency, but higher amplitude of N2 or P3. another major finding was that different correlation was found between gender,anxiety-depression,duration, education,BMI,sleep characteristics and N2 or P3.

DISCUSSION

Our study has revealed that sleep loss may influence the response inhibition ability in insomnia, not only on behavior level, but also on the electrophysiological level. Abnormal changes in inhibition process or inhibition supervision can be represented as N2/P3 components under Go/No-go condition. Additionally, correlation analysis has been found between gender, anxiety-depression, BMI, education, and sleep structure. Thus, sleep loss attenuates response inhibition and impairs executive function in insomnia participants.

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.

Sleeping poorly is robustly associated with a tendency to engage in spontaneous waking thought

We spend approximately-one third of our lives sleeping, and spontaneous thoughts dominate around 20-50% of our waking life, but little is known about the relation between the two. Studies examining this relationship measured only certain aspects of sleep and certain forms of spontaneous thought, which is problematic given the heterogeneity of both conceptions. The scarce literature suggests that disturbed sleep and the frequency of spontaneous waking thoughts are associated, however this could be caused by shared variance with negative affect. We report a comprehensive survey study with a large range of self-reported sleep and spontaneous thought measures (N = 236), showing that poorer sleep quality, more daytime-sleepiness, and more insomnia symptoms, consistently predicted higher tendencies to engage in disruptive spontaneous thoughts, independently of trait negative affect, age and gender. Contrarily, only daytime sleepiness predicted positive-constructive daydreaming. Findings underscore the role of sleep for spontaneous cognition tendencies.

Sleep well, mind wander less: A systematic review of the relationship between sleep outcomes and spontaneous cognition

Despite an upsurge of research on spontaneous cognition, little is known about its associations with sleep-related outcomes. This systematic review, following PRISMA guidelines, examined the relationship between sleep and spontaneous thoughts, across different definitions and measurements of sleep outcomes and spontaneous cognition, and a diversity of methodologies. Twenty-one articles with survey and/or experimental designs were identified. Self-reported disturbed sleep-comprising poor sleep quality, more insomnia symptoms, more daytime sleepiness and a tendency towards eveningness-and experimentally induced sleep deprivation were associated with a tendency to engage in disruptive mind wandering and daydreaming, but not positive-constructive daydreaming. Findings regarding circadian fluctuation in spontaneous thoughts were mixed and inconclusive. This systematic review bridges the gap between the sleep and spontaneous cognition research by contributing to the understanding of potential psychological and cognitive mechanisms of spontaneous cognition, as well as by elucidating the emotional and cognitive consequences of disturbed sleep.

Functional MRI Correlates of Sleep Quality in HIV

OBJECTIVE

To examine resting-state functional MRI (rs-fMRI) networks related to sleep in the context of HIV infection.

METHODS

rs-fMRI data were collected in 40 HIV-infected (HIV+) individuals at baseline (treatment-naive), 12 week (post-treatment) and one year timepoints. A group of 50 age-matched HIV-negative (HIV-) individuals were also imaged at baseline and one year timepoints. The Pittsburgh Sleep Quality Index (PSQI) questionnaire was administered at all timepoints. Using group independent component analysis (ICA), maps of functional networks were generated from fMRI data; from these, sleep-related networks were selected. A generalized linear model (GLM) was used to analyze if these networks were significantly associated with the PSQI score, and if this relationship was influenced by HIV status/treatment or timepoint.

RESULTS

HIV+ individuals had significantly lower PSQI score after treatment (p=0.022). Networks extracted from group ICA analysis included the anterior and posterior default mode network (DMN), central executive network (CEN), bilateral frontoparietal networks (FPNs), and the anterior cingulate cortex salience network (ACC SN). We found the posterior DMN, right FPN, and ACC SN GLMs showed significantly higher goodness-of-fit after incorporating PSQI data (p = 0.0204, 0.044, 0.044, respectively). Furthermore, the correlation between ACC SN and posterior DMN connectivity was significantly decreased in the HIV+ cohort.

CONCLUSION

Functional networks such as the DMN, FPN, CEN, and ACC SN are altered in poor sleep, as measured by the PSQI score. Furthermore, the relationship between these networks and PSQI is different in the HIV+ and HIV- populations.

Fidelity of Information Processing on a Psychomotor Vigilance Task Predicts Changes in Self-Reported Sleepiness Ratings

INTRODUCTION

Daytime sleepiness is a common problem. Although sleepiness is primarily assessed at the self-report unit of analysis, factors that contribute to an individual's experience and report of sleepiness remain poorly understood. While sleepiness is known to impact vigilance performance, the impact of vigilance performance on sleepiness reports is less well understood. We aimed to explore how performance on a psychomotor vigilance task (PVT) relates to changes in self-reported sleepiness in a rested condition.

METHODS

Participants were 66 adults (Mdn=23, range 18-49 years old), 47% female, 88% white, with a wide range of insomnia symptoms. Participants rated their sleepiness on a scale from 1 (not sleepy) to 10 (extremely sleepy) at the start (pre) and the end (post) of a 10-minute computerized PVT. Ordinal regression determined whether mean reciprocal reaction time, a measure of overall performance, or the log-transformed signal-to-noise ratio (LSNR), a measure of fidelity of information processing, predicted post-sleepiness, adjusting for pre-sleepiness, insomnia, and potential confounds.

RESULTS

Lower LSNR predicted greater change in sleepiness (pre-to-post PVT) and higher post-sleepiness even after adjusting for pre-sleepiness, mean reciprocal reaction time, insomnia, and other potential confounds (p<0.05).

DISCUSSION

When adjusting for insomnia symptoms and potential confounds, participants with lower fidelity of information processing reported higher sleepiness than they had reported at the start of the PVT. Possible mechanisms and explanations are discussed in relation to a 3-factor model of sleep-wake states. This line of research may contribute to innovative approaches to assessing and treating sleepiness.

Do hypnotics increase the risk of driving accidents or near miss accidents due to hypovigilance? The effects of sex, chronic sleepiness, sleep habits and sleep pathology

Driving accidents due to hypovigilance are common but the role of hypnotics is unclear in patients suffering from sleep disorders. Our study examined factors influencing accidents and near miss accidents attributed to sleepiness at the wheel (ANMAS). Using data from an online questionnaire aimed at patients with sleep disorders, we analysed the associations between ANMAS, sociodemographic data, symptoms of sleep disorders, severity of insomnia (Insomnia Severity Index (ISI)) symptoms of anxiety and depression (Hospital Anxiety and Depression scale with depression (HADD) and anxiety (HADA) subscales), chronic sleepiness (Epworth sleepiness scale ESS), hypnotic use and information about sleep habits. Hypnotics were hierarchically grouped into Z-drugs, sedative medication, melatonin and over the counter (OTC) alternative treatments. Of 10802 participants; 9.1% reported ANMAS (Men 11.1% women 8.3%) and 24.4% took hypnotics (Z-drugs 8.5%, sedative medication 8%, melatonin 5.6% and alternative treatments 2.5%). Logistic regression analysis identified the following risk factors for ANMAS: moderate (OR 2.4; CI: 2.10-2.79) and severe sleepiness (ESS OR 5.66; CI: 4.74-6.77), depression (HADD OR 1.2; CI: 1.03-1.47), anxiety (HADA OR 1.2;CI: 1.01-1.47), and insufficient sleep (OR1.4; CI: 1.2-1.7). Hypnotics were not associated with an increased risk of ANMAS in patients suffering from insomnia. Risk factors varied according to sex: in females, sex (OR 0.; CI: 0.55-0.74), mild insomnia (OR 0.5; CI: 0.3-0.8) and use of alternative treatments (OR 0.455, CI:0.23-0.89) were protective factors and risk was increased by sleepiness, sleep debt, social jetlag, caffeine use, anxiety and depression. In men no protective factors were identified: sleepiness, sleep debt, and severe insomnia were associated with an increased risk of ANMAS. In clinical practice, all patients with daytime sleepiness and men with severe insomnia should be counselled concerning driving risk and encouraged to avoid sleep debt.

The Attention Network Test Database: ADHD and Cross-Cultural Applications

Attention is a central component of cognitive and behavioral processes and plays a key role in basic and higher-level functioning. Posner's model of attention describes three components or networks of attention: the alerting, which involves high intensity states of arousal; the orienting, which involves the selective direction of attention; and the executive control, which involves cognitive functions such as conflict resolution and working memory. The Attention Network Test (ANT) is a computerized testing measure that was developed to measure these three networks of attention. This project describes the ANT, its widely used variants, and the recently developed ANT Database, a repository of data extracted from all studies that have used the ANT as of 2019. To illustrate the potential uses of the database, two meta-analyses conducted using the ANT Database are described. One explores task performance in children with and without attention deficit/hyperactivity disorder (ADHD). The other one explores regional differences between studies conducted in China, Europe, and the United States. We are currently in the process of integrating the database into a publicly available web interface. When that work is complete, researchers, clinicians, and the general public will be able to use the database to explore topics of interest related to attention.

Dysfunction of processing task-irrelevant emotional faces in primary insomnia patients: an evidence from expression-related visual MMN

PURPOSE

According to the cognitive processing perspectives, patients with insomnia have insufficient neural management of expressional information. In this study, we compared the pre-attentive processing function of task-irrelevant facial expressions in patients with primary insomnia (PI) and matched healthy controls, with expression-related mismatch negativity (EMMN) elicited by emotional faces as the indicator.

METHODS

Using three schematic facial expressions (neutral, happy, and sad) as task-irrelevant stimuli, we investigated the visual processing of PI patients (n = 22) and healthy subjects (n = 22) in an expression-related oddball paradigm designed to elicit the visual N170 and EMMN component. After recording and analyzing the electroencephalogram of all participants, amplitude analysis of N170 and EMMN was eventually conducted under corresponding time window.

RESULTS

Compared with control group, the amplitude of sad-EMMN component was significantly attenuated in patients with PI, while no remarkable difference was observed under the happy condition. In addition, negative cognitive bias was further validated in the control group, but not presented in the PI group.

CONCLUSION

The current data suggest dysfunctional expressional information processing in PI patients, accompanied by the disorganization of high level perceptual strategy of processing facial emotional expression.

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.

Insomnia and Cognitive Performance

Insomnia is the most common sleep problem, affecting between 30% and 50% in the general adult population. Insomnia is characterized by difficulty initiating and maintaining sleep, along with dissatisfaction with sleep quality or quantity. Insomnia complaints are linked to clinically significant distress or impairment in key areas of functioning, especially daytime cognitive performance. Cognitive impairments related to insomnia are subtle, and may represent distinct differences from those seen in other sleep disorders. This article updates and summarizes the recent literature investigating cognitive impairments in individuals with insomnia, and identifies the cognitive domains of functioning that are consistently impaired.

Insomnia and cognitive performance: A systematic review and meta-analysis

Cognitive performance has been extensively investigated in relation to insomnia, yet review of the literature reveals discrepant findings. The current study aimed to synthesize this literature with a systematic review and meta-analysis. 48 studies (k = 50 independent samples, n = 4539 total participants) met inclusion criteria. Omnibus meta-analysis revealed insomnia was associated with poorer overall cognitive performance (Hedge's g = -0.24, p < 0.001). Analyses by cognitive domain revealed insomnia was specifically associated with impairments in subjective cognitive performance (g = -0.35), and objective measures of perceptual function (g = -0.24), manipulation (g = -0.52) and retention/capacity in working memory (g = -0.30), complex attention (g = -0.36), alertness (g = -0.14), episodic memory (g = -0.29), and problem solving in executive functions (g = -0.39). Age, percent female, publication year, and insomnia measure did not consistently moderate findings. Approximately 44% of studies failed to use diagnostic criteria when categorizing insomnia and cognitive measures varied widely. This indicates a need for standardization of methods assessing insomnia and cognitive performance in research. Overall, findings from this meta-analysis indicate insomnia is associated with impairment in objective and subjective cognitive performance, highlighting the utility of treating insomnia to potentially improve cognitive outcomes.

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.

Self-Reported Sleep, Anxiety, and Cognitive Performance in a Sample of U.S. Military Active Duty and Veterans

Unhealthy sleep can interfere with U.S. military service members affective and cognitive functioning, and increase accident and injury risks. This study examined the relationship between U.S. active duty and veterans' (n = 233) self-reported sleep (Pittsburgh Sleep Quality Index), anxiety (Zung Self-Rating Anxiety Scale), and cognitive performance (Automated Neuropsychological Assessment Metric). Statistical analyses included Pearson product moment correlations and multivariate analysis of variance, with Tukey-b post-hoc tests, with a p < 0.05 significance level. Higher education, abstinence from sleep aids, longer time in active duty service, and being on active duty were correlated with better sleep and lower anxiety. Greater sleep disturbance, poor sleep quality, and sleepiness-related daytime dysfunction were associated with greater anxiety and slower response times, and lower response accuracy. Statistically controlling for anxiety diminished the magnitude and significance of the correlations between sleep and cognitive performance, suggesting that reducing anxiety will improve sleep and diminish cognitive performance effects. These findings suggest the need for addressing both sleep and anxiety for those with diagnosed sleep disorders, as well as using a procedural systems approach to decrease anxiety during missions that demand outstanding cognitive performance.

Executive Functions in Insomnia Disorder: A Systematic Review and Exploratory Meta-Analysis

Background: Executive functions (EFs) are involved in the control of basic psychological processes such as attention and memory and also contribute to emotion regulation. Research on the presence of EFs impairments in insomnia yielded inconsistent results. Therefore, we performed a systematic review of the literature on three EFs: inhibitory control, working memory, and cognitive flexibility in adults with insomnia in order to investigate the presence and magnitude of insomnia-related EFs impairments. Methods: PubMed, Scopus, Medline, and PsycINFO were searched. Risk of bias assessment of included studies was performed by two independent researchers. Findings were summarised using both a narrative approach and meta-analysis. Cohen's d was calculated at 95% confidence interval (CI) as effect size of between groups differences. Results: Twenty-eight studies comparing adult individuals with a diagnosis of insomnia and healthy controls on neuropsychological measures of EFs were included. Narrative synthesis revealed substantial variability across study findings. Factors that were primarily hypothesised to account for this variability are: objective sleep impairments and test sensitivity. Exploratory meta-analysis showed impaired performance of small to moderate magnitude in individuals with insomnia as compared to controls in reaction times, but not accuracy rates, of inhibitory control (d = -0.32, 95% CI: -0.52 to -0.13) and cognitive flexibility tasks (d = -0.30, 95% CI: -0.59 to -0.01). Performance in working memory tasks was also significantly impacted (d = -0.19, 95% CI: -0.38 to -0.00). Effects sizes were larger when insomnia was associated with objective sleep impairments, rather than normal sleep. Conclusions: We gathered evidence supporting small to moderate deficits in EFs in individuals with insomnia. Due to the small sample size results should be considered preliminary and interpreted carefully.

Brain iron deposition in primary insomnia-An in vivo susceptibility-weighted imaging study

BACKGROUND

To study the brain iron deposition and its relationships with cognitive impairment and sleep quality in primary insomnia (PI).

METHODS

Thirty-five patients with PI and 35 volunteers underwent MRI scanning using high-resolution susceptibility-weighted imaging sequence. Bilateral anterior cingulate cortices, posterior cingulate cortex, hippocampus, caudate nucleus, globus pallidus, putamen, thalamus, red nucleus, substantia nigra, parietal cortex, and frontal white matter were selected as regions of interest. The phase shift values of the above areas were compared between the two groups. Partial correlations between phase shifts values and neuropsychological scale scores including Pittsburgh Sleep Quality Index, Insomnia Severity Index, Mini Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), Activities of Daily Living Scale, and Clinical Dementia Rating of the PI patients were analyzed.

RESULTS

Compared with the normal controls, the PI patients showed significant lower MMSE and MoCA scores and increased phase shift values in the left caudate nucleus, left putamen, left hippocampus, and bilateral thalamus (p < 0.05). Close correlation was found between the phase shift value of the left hippocampus and the MMSE scores of the PI patients (R = -0.447, p < 0.01).

CONCLUSION

The PI patients exhibited significant cognitive impairment and increased iron deposition in several brain regions. The iron concentration of the left hippocampus is a biomarker of cognitive impairment and may play an important role in the pathophysiological mechanism.

Psychomotor Vigilance Impairment During Total Sleep Deprivation Is Exacerbated in Sleep-Onset Insomnia

PURPOSE

Individuals with primary insomnia frequently report cognitive impairment as a next-day consequence of disrupted sleep. Studies attempting to quantify daytime impairment objectively in individuals with insomnia have yielded mixed results, with evidence suggesting impairments in aspects of executive functioning but not psychomotor vigilance. It has been suggested that persons with insomnia may have latent performance deficits for which they would be able to compensate effectively under normal daytime circumstances - suggesting that any such deficits may be exposed through perturbation. In this context, we used a laboratory-based total sleep deprivation (TSD) paradigm to investigate psychomotor vigilance performance in individuals with chronic sleep-onset insomnia as compared to healthy normal controls.

PARTICIPANTS AND METHODS

Fourteen participants, seven individuals with chronic sleep-onset insomnia (ages 24-40y) and seven age-matched, healthy normal sleepers completed a highly controlled in-laboratory study involving 38 h of TSD. A 10 min and a 3 min version of the psychomotor vigilance test (PVT) were administered every 3 h during TSD.

RESULTS

In both the individuals with sleep-onset insomnia and the age-matched normal sleepers, lapses of attention and false starts on the PVT were relatively infrequent during the first 16 h of the TSD period, but increased significantly when wakefulness was extended beyond 16 h. However, the effects of TSD on PVT performance were considerably exacerbated in the sleep-onset insomnia group, which showed about twice as many lapses of attention, more than twice as many false starts, and approximately twice as big a time-on-task effect on the 10 min PVT as the age-matched normal sleepers group, with similar findings on the 3 min PVT.

CONCLUSION

These findings indicate that daytime impairment reported by individuals with sleep-onset insomnia has an objective performance component that is exposed during TSD. Thus, persons with sleep-onset insomnia could be at increased risk of performance impairment in settings that involve extended wakefulness. This underscores the importance of treating insomnia and suggests that laboratory sleep deprivation studies could serve to document the effectiveness of treatment approaches.

Post-Hoc Analyses of the Effects of Baseline Sleep Quality on SHP465 Mixed Amphetamine Salts Extended-Release Treatment Response in Adults with Attention-Deficit/Hyperactivity Disorder

OBJECTIVE

Sleep problems are common in adults with attention-deficit/hyperactivity disorder (ADHD). The presence of sleep problems at the time of presentation for ADHD treatment could impact the level of improvement in ADHD symptoms or executive function occurring with ADHD pharmacotherapy. Therefore, we examined the influence of baseline sleep quality on the effects of SHP465 mixed amphetamine salts (MAS) extended-release.

METHODS

Adults (18-55 years) with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision-defined ADHD and baseline ADHD Rating Scale IV (ADHD-RS-IV) total scores ≥ 24 were randomized to once-daily SHP465 MAS (12.5-75 mg) or placebo in a 7-week, double-blind, dose-optimization study. Post-hoc analyses evaluated SHP465 MAS treatment effects on ADHD symptoms, using the ADHD-RS-IV, and executive function, using the Brown Attention-Deficit Disorder Scale (BADDS), based on baseline sleep quality as defined by Pittsburgh Sleep Quality Index (PSQI) scores [sleep quality impaired (PSQI total score > 5; PSQI component scores 2 or 3) versus not impaired (PSQI total score ≤ 5; PSQI component scores 0 or 1)]. Analyses were conducted in the intent-to-treat population.

RESULTS

Of 280 enrolled participants, 272 were randomized (placebo, n = 135; SHP465 MAS, n = 137). The intent-to-treat population consisted of 268 participants (placebo, n = 132; SHP465 MAS, n = 136), and 170 participants (placebo, n = 76; SHP465 MAS, n = 94) completed the study. Treatment differences nominally favored SHP465 MAS over placebo in both sleep impairment groups regarding ADHD-RS-IV total score changes (all nominal p < 0.05), except for those with impairment defined by sleep efficiency (p = 0.2696), and regarding BADDS total score changes (all nominal p < 0.05), except for those with impairment defined by sleep duration (p = 0.1332) and sleep efficiency (p = 0.8226). There were no statistically significant differences in SHP465 MAS treatment effects between sleep impairment groups.

CONCLUSIONS

Improvements in ADHD symptoms and executive function occurred with dose-optimized SHP465 MAS, regardless of baseline impairment in some aspects of sleep in adults with ADHD, with no significant differences observed as a function of sleep impairment.

CLINICAL TRIALS REGISTRATION

ClinicalTrials.gov identifier-NCT00150579.

Excessive daytime sleepiness in asthma: What are the risk factors?

OBJECTIVE

Previous studies have found that excessive daytime sleepiness (EDS) is a more common problem in asthmatic subjects than in the general population. The aim of this study was to investigate whether the prevalence of EDS is increased in asthmatic subjects and, if so, to analyse the occurrence of potential risk factors for EDS in asthmatics.

METHODS

Cross-sectional epidemiological study. In 2008, a postal questionnaire was sent out to a random sample of 45,000 individuals aged 16-75 years in four Swedish cities.

RESULTS

Of the 25,160 persons who participated, 7.3% were defined as having asthma. The prevalence of EDS was significantly higher in asthmatic subjects (42.1% vs. 28.5%, p < 0.001) compared with non-asthmatic subjects. Asthma was an independent risk factor for EDS (adjusted OR 1.29) and the risk of having EDS increased with asthma severity. Risk factors for EDS in subjects with asthma included insomnia (OR, 3.87; 95% CI, 3.10-4.84); chronic rhinosinusitis (OR, 2.00; 95% CI, 1.53-2.62); current smoking (OR, 1.60; 95% CI, 1.15-2.22) and obesity (OR, 1.53; 95% CI, 1.09-2.13).

CONCLUSIONS

EDS is a common problem among subjects with asthma. Asthma is an independent risk factor for having EDS. Furthermore, subjects with asthma often have other risk factors for EDS, many of them potentially modifiable.

Impaired visual processing in patients with insomnia disorder revealed by a dissociation in visual search

Insomnia disorder is associated with both subjective and objective daytime impairments. In particular, cognitive impairments are frequently reported. However, little is known about the effects of this pathology on perceptual processes. In this study we aim at evaluating the effect of insomnia disorder on visual processing by employing a visual search paradigm. Twenty-three patients with insomnia disorder and 20 healthy age- and sex-matched control subjects participated in the study. After a polysomnographic recording night patients performed a visual search task in which they had to respond to the presence/absence of a target (letter T) embedded into a set of distractors (letters Os, Xs or Ls). Target's salience and distractors' numerosity were manipulated, while accuracy and reaction times were recorded as dependent variables. The results mainly confirmed the typical effects of a visual search task. An overall delay in performing the task was observed for patients with insomnia disorder. However, distinguishing the reaction times to stimuli containing the target from reaction times to stimuli in which the target was absent, the clinical group differed from controls solely in the condition of target absent. The performance (reaction times) of the subjects correlated with the age in the control group, whereas no correlation between reaction times and age, disease duration and quality of sleep was found in patients with insomnia disorder. These results experimentally demonstrate the presence of a daytime impairment in patients with insomnia disorder revealed by a dissociation in visual search, and are discussed in the light of the hyperarousal concept of insomnia.

Executive dysfunction in patients with chronic primary insomnia treated with clonazepam

Clonazepam (CNZ) is a drug used for insomnia treatment. Our objective was to search CNZ effects on executive functions (EF) in patients with chronic primary insomnia (CPI)-CNZ treated. Ninety participants were studied divided into three groups: a group of patients with CPI only (n = 30), a group of patients with CPI-CNZ treated (n = 30) and a healthy control drug-free subjects group (n = 30). EF were examined by means of E-Prime and by the Tower of London tests. Data of the EF were compared between groups, and correlation calculations between EF and CNZ dose were performed. Patients with CPI-CNZ treated showed more deleterious effects on EF (attention, inhibition, working memory, planning, cognitive flexibility, and monitoring) than patients with CPI only. Attention and cognitive flexibility correlated with CNZ dose. In conclusion, CNZ treatment was associated with deficits in some EF in patients with CPI-CNZ treated compared to CPI only and controls. We found a dose dependency between CNZ and some EF deficits.

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

OBJECTIVE

Cognitive impairment is associated with insomnia. However, there is a lack of evidence suggesting a link between insomnia and cognitive dysfunction in objective testing. The objectives of our current study were to assess the differences in components of attentional performance between primary insomnia patients and normal-sleeping controls and to examine potential predictors of attention impairment in patients with insomnia.

METHODS

We studied 36 patients (age 40.39 ± 12.36 years; 57.1% male) with insomnia and 25 normal-sleeping controls (age 39.88 ± 12.50 years; 52.9% male) who underwent one-night polysomnography followed by Multiple Sleep Latency Test (MSLT) and Attention Network Task (ANT). ANT reflected three attentional networks termed the alerting, orienting, and executive control networks.

RESULTS

After controlling for age, gender, body mass index, depression, anxiety, and education levels, patients with insomnia scored higher on the executive control variable of the ANT compared with normal-sleeping controls (96.75 ± 7.60 vs. 57.00 ± 10.49, p = 0.01). This higher score was independently associated with insufficiency of slow-wave sleep during nighttime sleep (β = -0.38, p = 0.04).

CONCLUSION

Our findings suggest that insomnia is associated with deficits in executive control of attention and that the underlying mechanism may be insufficiency of slow-wave sleep in chronic insomnia.