Extreme sleep state misperception: From psychopathology to objective-subjective sleep measures

Study objectives: We tested the hypothesis that patients with extreme sleep state misperception display higher levels of psychopathology and reduced quantitative estimation abilities compared to other patients with insomnia. Secondary aims included the evaluation of group differences in subjective self-reported quality of life and sleep quality and objective sleep parameters. Methods: In this cross-sectional, observational study, 249 patients with insomnia underwent a video-polysomnography with a subsequent morning interview to assess self-reported sleep estimates and filled in a large battery of questionnaires. Patients were classified into High Misperception (HM) and Moderate Misperception (MM) groups, according to the complement of the ratio between self-reported total sleep time and objective total sleep time (Misperception Index). Results: No significant differences emerged in any of the psychopathological measures considered between the HM and the MM group. Similarly, no effect was observed in quantitative estimation abilities. HM patients displayed a significantly increased number of awakenings per hour of sleep and a reduced dream recall rate. Their overall sleep quality and quality of life was significantly impaired. Conclusions: Future research on sleep misperception should focus on factors other than the level of psychopathology and estimation abilities, in particular sleep microstructure and quantitative EEG studies in both REM and NREM slee

Electrophysiological and Neuropsychological Indices of Cognitive Dysfunction in Patients with Chronic Insomnia and Severe Benzodiazepine Use Disorder.

Benzodiazepine (BDZ) misuse is a growing health problem, with 1-2% of patients under BDZ treatment meeting the criteria for use disorder or dependence. Although BDZ addiction potential has been known for decades, much remains unknown its effects on brain functions. The aim of this study was to assess the neuropsychological and neurophysiological profile of a group of chronic insomniacs taking long-term high doses of benzodiazepine. We recruited 17 consecutive patients admitted to our third-level Sleep Medicine Unit for drug discontinuation (7 males, mean age 49.2 ± 11.2 years, mean education 13.7 ± 3.9 years, mean daily diazepam-equivalent BDZ: 238.1 ± 84.5 mg) and 17 gender/age-matched healthy controls (7 males, mean age 46.8 ± 14.1 years, mean education 13.5 ± 4.5 years). We performed a full neuropsychological evaluation of all subjects and recorded their scalp event-related potentials (Mismatch-Passive Oddball-Paradigm and Active Oddball P300 Paradigm). Patients with chronic insomnia and BDZ use disorder showed a profound frontal lobe executive dysfunction with significant impairment in the cognitive flexibility domain, in face of a preserved working, short and long-term memory. In patients, P300 amplitude tended to be smaller, mainly over the frontal regions, compared to controls. BDZ use disorder has a severe cognitive impact on chronic insomnia patients. Long-term high-dose BDZ intake should be carefully evaluated and managed by clinicians in this specific patient population, especially in relation to risky activities

Assessing Sleep Habits in Italian Community-Dwelling Adolescents: Psychometric Properties of the School Sleep Habits Survey Scales

Background. In the field of adolescent sleep research, different sleep surveys have been implemented; however, psychometric properties of these instruments have been investigated only minimally. Methods. In order to assess the psychometric properties of the Sleep–Wake Problems Behaviour Scale (SWP), the Sleepiness Scale (SLS), and the Morningness/Eveningness Questionnaire (ME), a moderately large sample of community-dwelling Italian adolescents (N = 778; 59.8% female; mean age = 15.77 years) was administered the Italian translation of the School Sleep Habits Survey. Results. Internal consistency estimates values were satisfactory for all measures; dimensionality analyses suggested a unidimensional structure for SWP, SLS and ME, respectively. Goodness-of-fit statistics for the one-factor model of the SLS, SWP, and ME scale items were adequate for all measures. Non-redundant taxometric analysis results consistently suggested a dimensional latent structure for the SLS, SWP, and ME, respectively. Conclusion. Our findings supported the use of the SLS, SWP, and ME total scores as measures of sleepiness, sleep-wake problem, and morningness/eveningness, at least among Italian community-dwelling adolescents, and encourage practitioners to rely on the conventional percentiles in order to interpret the SLS, SWP, and ME total scores

Obstructive sleep apnea: brain structural changes and neurocognitive function before and after treatment

The paper assesses the effect of obstructive sleep apnea on brain structure and cognitive performance, and the changes after treatment with Continuous Positive Airway Pressure. The main finding is that cognitive impairment is associated with a decrease of grey-matter volume in specific cerebral regions, and that these can be reversed by treatment with an increase of grey-matter volume in specific hippocampal and frontal brain regions. These changes are significantly correlated with the improvement in specific neuropsychological tests (executive-functioning and short-term memory), underlining the importance of early diagnosis and treatment of sleep apnea. Specific neuropsychological measures represent valuable tools for the assessment of therapy success, and can offer the evidence that adherence to treatment can lead not only to clinical, but also to brain-structural, recovery. Objectives: To investigate the cognitive deficits and the corresponding brain morphology changes in OSA, and the modifications after treatment, using combined neuropsychological testing and Voxel-Based-Morphometry. Methods: 17 treatment-naïve sleep apnea patients and 15 age-matched healthy controls. All underwent a sleep study, cognitive tests and magnetic resonance imaging. After threemonths treatment, cognitive and imaging data were collected to assess therapy efficacy. Measurements and Main Results: Neuropsychological results in pre-treatment OSA showed impairments in most cognitive areas, as well as in mood and sleepiness. These impairments were associated with focal reductions of grey-matter volume in the left hippocampus (enthorinal cortex), left posterior parietal cortex and right superior frontal gyrus. After treatment, we observed significant improvements involving memory, attention and executive-functioning that paralleled grey-matter volume increases in hippocampal and frontal structures. Conclusions: The cognitive and structural deficits in obstructive sleep apnea may be secondary to sleep deprivation and repetitive nocturnal intermittent hypoxemia. These negative effects may be recovered by consistent and throughout treatment. Our findings highlight the importance of early diagnosis and successful treatment of this disorder

Sleep apnea: Altered brain connectivity underlying a working-memory challenge

Obstructive sleep apnea (OSA) is characterized by the frequent presence of neuro-cognitive impairment. Recent studies associate cognitive dysfunction with altered resting-state brain connectivity between key nodes of the executive and default-mode networks, two anti-correlated functional networks whose strength of activation increases or decreases with cognitive activity, respectively. To date no study has investigated a relationship between cognitive impairment in OSA and brain connectivity during an active working-memory challenge. We thus investigated the effect of OSA on working-memory performance and underlying brain connectivity.OSA patients and matched healthy controls underwent functional magnetic resonance imaging (fMRI) scanning while performing a 2-back working-memory task. Standard fMRI analyses highlighted the brain regions activated at increasing levels of working-memory load, which were used as seeds in connectivity analyses. The latter were based on a multiregional Psycho-Physiological-Interaction (PPI) approach, to unveil group differences in effective connectivity underlying working-memory performance.Compared with controls, in OSA patients normal working-memory performance reflected in: a) reduced interhemispheric effective connectivity between the frontal “executive” nodes of the working-memory network, and b) increased right-hemispheric connectivity among regions mediating the “salience-based” switch from the default resting-state mode to the effortful cognitive activity associated with the executive network. The strength of such connections was correlated, at increasing task-demands, with executive (Stroop test) and memory (Digit Span test) performance in neuro-cognitive evaluations.The analysis of effective connectivity changes during a working-memory challenge provides a complementary window, compared with resting-state studies, on the mechanisms supporting preserved performance despite functional and structural brain modifications in OSA. Keywords: Obstructive sleep apnea, Executive functions, Working-memory, fMRI, Cognitive disorders, Brain connectivit

Prevalence of habitual snoring and sleep-disordered breathing in preschool-aged children in an Italian community

Objective: To measure the prevalence of habitual snoring and sleep-disordered breathing in preschool-aged children. Study design: Cross-sectional survey with parental report and overnight ambulatory monitoring of children 3 to 6 years of age in 8 kindergartens (n = 604). Parents reported the child's information through an interviewer-based questionnaire or by a brief telephone interview. Snoring, oxygen saturation, body position, and heart rate were recorded for 1 night at home. Results: Data were obtained on 98.5% of 604 children (447 questionnaires, 74%; 148 telephone interviews, 24.5%); groups were similar for sex and age. Two hundred sixty-five children had ambulatory monitoring at home. Habitual snoring (always and often) was reported in 34.5% and breathing cessation in 18.6%. Habitual snoring was associated with parental report of daytime symptoms (P = .001) and daytime somnolence (P = .032). Pathologic snoring was present in 12% of children (95% CI, 7.9-16.1). On multivariate analysis, parental report of habitual snoring was the strongest determinant of pathologic snoring (OR, 12.23; 95% CI, 3.56-41.94). Oxygen desaturation index ≥5 per hour was found in 13% of children (95% CI, 8.7-17.3). Conclusions: Parental report of habitual snoring is very common. Children with habitual snoring are more likely to have objectively measured snoring and daytime morbidity

Extreme sleep state misperception: from psychopathology to objective-subjective sleep measures

Study objectives: We tested the hypothesis that patients with extreme sleep state misperception display higher levels of psychopathology and reduced quantitative estimation abilities compared to other patients with insomnia. Secondary aims included the evaluation of group differences in subjective self-reported quality of life and sleep quality and objective sleep parameters. Methods: In this cross-sectional, observational study, 249 patients with insomnia underwent a videopolysomnography with a subsequent morning interview to assess self-reported sleep estimates and filled in a large battery of questionnaires. Patients were classified into High Misperception (HM) and Moderate Misperception (MM) groups, according to the complement of the ratio between self-reported total sleep time and objective total sleep time (Misperception Index). Results: No significant differences emerged in any of the psychopathological measures considered between the HM and the MM group. Similarly, no effect was observed in quantitative estimation abilities. HM patients displayed a significantly increased number of awakenings per hour of sleep and a reduced dream recall rate. Their overall sleep quality and quality of life was significantly impaired. Conclusions: Future research on sleep misperception should focus on factors other than the level of psychopathology and estimation abilities, in particular sleep microstructure and quantitative EEG studies in both REM and NREM sleep

The paradox of paradoxical insomnia: A theoretical review towards a unifying evidence-based definition

Paradoxical insomnia is one of the most intriguing yet challenging subtypes of insomnia. Despite being recognized for a long time by the international community, it is still unclear whether this entity really exists, which are its features and boundaries. Much of the debate is fuelled by the lack of a consensus on its precise definition. To help filling some of the existing gaps, a systematic review of the literature was conducted, through which 19 different quantitative definitions were obtained. These definitions were then applied to two distinct datasets. The first consisted of 200 chronic primary insomnia patients, diagnosed according to the DSM-IV-TR criteria. The second consisted of 200 age- and sex-matched healthy persons without insomnia. For each dataset, available data from the objective sleep parameters and their subjective estimation were imported and analysed in MATLAB. Depending on the definition used, the prevalence of paradoxical insomnia ranged from 8 to 66%, while agreement between different definitions ranged from −0.19 to 0.9 (using Cohen's kappa coefficient). Based on the results garnered, necessary features for a quantitative definition of paradoxical insomnia were identified. Several open questions remain, such as whether there is a minimum number of hours a patient should sleep to fulfill the criteria for a diagnosis of paradoxical insomnia, and whether sleep latency can be used in the definition along with total sleep time. We conclude by advocating continued study of paradoxical insomnia and sleep state misperception and by providing specific directions for future research. The current understanding of paradoxical insomnia and, more broadly, of sleep state misperception, is greatly hampered by the lack of agreement on a quantitative and evidence-base measure of the discrepancy between subjective and objective sleep evaluation. The current study provides a critical analysis about the strength and the limitations of the available definitions, using both a data-driven and a theory-driven approach. The overarching goal is to motivate a rigorous discussion involving the main experts of the field, to build a consensus, and develop an evidence-based measure of sleep state misperception and/or of paradoxical insomnia