[Chronobiological aspects of bipolar disorder]. / Chronobiologische Aspekte der bipolaren Störung.

BACKGROUND: Numerous symptoms of bipolar disorder are regulated by the circadian rhythm. Because of this association it is assumed that disruption of the circadian rhythm may be part of the pathomechanism of bipolar disorder. OBJECTIVES: A comparison and subsequent critical discussion of the current data situation on chronobiological aspects of bipolar disorder are presented. METHODS: A narrative literature search was carried out and the main findings are presented in a summarized form. RESULTS: There are a large number of animal and human studies investigating the connection between disorders of the circadian rhythm and bipolar disorder. Especially chronotype, the environmental factor light and sleep disorders seem to be associated with the development of bipolar disorder. CONCLUSIONS: The neurobiology of bipolar disorder shows numerous chronobiological aspects. There is evidence for a direct connection of disruption of the circadian rhythm and development and progression of bipolar disorder; however, at present there is no proof for the specificity of these findings for bipolar disorder. Future studies should consolidate the evidence on the impact of disorders of the circadian rhythm on the pathomechanism of bipolar disorder.

Sleep quality does not mediate the negative effects of chronodisruption on body composition and metabolic syndrome in healthcare workers in Ecuador.

BACKGROUND AND AIMS: The objective of the present work was to determine to what extent sleep quality may mediate the association between chronodisruption (CD) and metabolic syndrome (MS), and between CD and body composition (BC). METHODOLOGY: Cross-sectional study which included 300 adult health workers, 150 of whom were night shift workers and thereby exposed to CD. Diagnosis of MS was made based on Adult Treatment Panel III criteria. Sleep quality was measured using the Pittsburgh Sleep Quality Index. Body mass index (BMI), fat mass percentage, and visceral fat percentage were measured as indicators of body composition (BC). Data were analyzed using logistic, linear regression and structural equation models. RESULTS: The odds of health workers exposed to CD to suffer MS was 22.13 (IC95 8.68-66.07) when the model was adjusted for age, gender, physical activity and energy consumption. CD was also significantly associated with an increase in fat mass and visceral fat percentages, but not to BMI. Surprisingly, there was not enough evidence supporting the hypothesis that sleep quality contributes to the association between CD and MS or between CD and BC. CONCLUSIONS: Sleep quality does not mediate the negative effects of CD on MS nor on BC.

Sleep Fragmentation and Cognitive Trajectories After Critical Illness.

BACKGROUND: ICU survivors can experience both cognitive dysfunction and persistent sleep disturbances after hospitalization. Sleep disturbances have been linked with cognitive impairment in various patient populations, and the apolipoprotein E (APOE) genotype has been linked to sleep-related impairments in cognition. RESEARCH QUESTION: Is there an association between sleep, long-term cognition, and APOE status in ICU survivors? STUDY DESIGN AND METHODS: We enrolled 150 patients from five centers who had been mechanically ventilated for at least 3 days; 102 patients survived to ICU discharge. Actigraphy and cognitive testing were undertaken at 7 days, 6 months, and 12 months after ICU discharge, and sleep duration, quality, and timing were estimated by actigraphy. APOE single nucleotide polymorphisms were assessed for each patient. RESULTS: Actigraphy-estimated sleep fragmentation, but not total sleep time or interdaily stability (estimate of circadian rhythmicity), was associated with worse cognitive impairment at 7 days of ICU discharge. No actigraphy-estimated variable of sleep estimation at 7 days post-ICU discharge predicted cognitive impairment or persistent sleep abnormalities at 6 and 12 months of follow-up in subsequently assessed survivors. Possessing the APOE ε4 allele was not significantly associated with sleep disturbances and its presence did not modify the risk of sleep-related cognitive impairment at follow-up. INTERPRETATION: Sleep fragmentation estimated by actigraphy was associated with worse cognitive performance in hospital, but not at later time intervals. Further research is needed to better delineate the relationship between persistent sleep disturbances and cognition in larger numbers of ICU survivors. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT02086877; URL: www.clinicaltrials.gov.

Association of Circadian Abnormalities in Older Adults With an Increased Risk of Developing Parkinson Disease.

Importance: Disruption in circadian activity rhythms is very common in older adults, particularly among those with neurodegenerative diseases, including Parkinson disease (PD). However, whether circadian disruption could be a prodrome for PD is unclear. Objective: To determine the association between rest-activity rhythm (RAR) and risk of incident PD and to explore whether this association is independent of nighttime sleep disturbances. Design, Setting, and Participants: The ancillary sleep study of the longitudinal cohort Osteoporotic Fractures in Men Study (MrOS) was conducted from December 1, 2003, to March 31, 2005. Of the 3135 community-dwelling men enrolled in the MrOS sleep study, 3049 had technically adequate RAR data; of these, 119 were excluded for having prevalent PD or missing incident data, leaving 2930 men without PD at baseline. Data were analyzed from February 1 through August 31, 2019. Exposures: Twenty four-hour RAR parameters (amplitude, mesor, robustness, and acrophase) generated by wrist actigraphy-extended cosinor analysis. Main Outcomes and Measures: Incident PD based on physician diagnosis. Multivariable logistic regression was used to determine the association between quartiles of RAR parameters and risk of incident PD. Results: Among the 2930 men included in the analysis (mean [SD] age, 76.3 [5.5] years), 78 (2.7%) developed PD during 11 years of follow-up. After accounting for all covariates, the risk of PD increased with decreasing circadian amplitude (strength of the rhythm) (odds ratio [OR] per 1-SD decrease, 1.77; 95% CI, 1.30-2.41), mesor (mean level of activity) (OR per 1-SD decrease, 1.64; 95% CI, 1.22-2.21), or robustness (how closely activity follows a cosine 24-hour pattern) (OR per 1-SD decrease, 1.54; 95% CI, 1.14-2.07) (P < .005 for trend). Those in the lowest quartile of amplitude, mesor, or robustness had approximately 3 times the risk of developing PD compared with those in the highest quartile of amplitude (OR, 3.11; 95% CI, 1.54-6.29), mesor (OR, 3.04; 95% CI, 1.54-6.01), and robustness (OR, 2.65; 95% CI, 1.24-5.66). The association remained after further adjustment for nighttime sleep disturbances and duration in the lowest compared with the highest quartile (OR for amplitude, 3.56 [95% CI, 1.68-7.56]; OR for mesor, 3.24 [95% CI, 1.52-6.92]; and OR for robustness, 3.34 [95% CI, 1.45-7.67]). These associations were somewhat attenuated, but the pattern remained similar after excluding PD cases developed within 2 years after baseline in the lowest compared with the highest quartile (OR for amplitude, 2.40 [95% CI, 1.15-5.00]; OR for mesor, 2.76 [95% CI, 1.35-5.67]; and OR for robustness, 2.33 [95% CI, 1.07-5.07]). Acrophase was not significantly associated with risk of PD. Conclusions and Relevance: In this cohort study, reduced circadian rhythmicity was associated with an increased risk of incident PD, suggesting it may represent an important prodromal feature for PD. Future studies are needed to determine whether circadian disruption could also be a risk factor for PD and whether strategies to improve circadian function affect the risk of PD.

The relationship between diurnal blood pressure abnormalities and target organ damage in normotensive subjects. Which is more important? Increased blood pressure levels or circadian blood pressure abnormalities.

Objective: Circadian blood pressure (CBP) abnormalities are well-known risk factors for many diseases such as cardiovascular, cerebrovascular, and chronic kidney disease. The object of this study was to evaluate the relationship between abnormalities in CBP rhythm and target organ damage (TOD) in normotensive non-dipper (non-DP) subjects.Methods: The 24-h ambulatory BP monitoring (ABPM) and echocardiography were performed and urinary albumin excretion (UAE) was measured in 127 normotensive dipper (DP) (42 males, 85 females) and 337 (89 males, 248 females) normotensive non-DP subjects.Results: When we compared DP and non-DP subjects; Pulse wave velocity (PWV) (7.12 ± 1.72 vs 7.57 ± 1.87 m/s, p = 0.02), the percentile of corrected PWV (cPWV) (7.1 vs. 20.2, p= 0.001) and the percentile of corrected augmentation index (cAIx) (23.5 vs. 33.9, p = 0.03), left ventricle mass index (LVMI) (78.00 ± 23.27 vs. 95.59 ± 18.29 g/m2, p = 0.01), relative wall thickness (RWT)(0.36 ± 0.13 vs 0.46 ± 0.09, p = 0.01), percentile of proteinuria (8.6 vs 29.2%, p = 0.00) were higher in non-DP group. In the correlation analyses, the PWV, LVMI, RWT were negatively correlated with the rate of systolic fall in nighttime (%)(-0.15, p = 0.01 vs. -0.23, p = 0.02 vs. -0.27, p = 0.00). It was observed that cPWV, cAIx, and UAE were independently associated with age and non-DP status (NDS), in logistic regression analysis.Conclusions: Our results suggested that normotensive persons with CBP abnormalities had TOD. In light of the data of this article, non-dipper status is detected in the early period and if the provision of diurnal blood pressure rhythm may reduce the incidence of future adverse events in nondipper normotensive subjects.

Challenging Circadian Rhythm Disorder Cases.

The complex interplay of the sleep and circadian systems, which are substantially differentially regulated, provides for plasticity that is expressed in health and disease. The classic circadian rhythm disorders are readily recognizable, but atypical forms can be identified by actigraphy and melatonin profilometry. Although the dim-light melatonin onset test maps the start of the biological night, 24-hour mapping can define the limits of the biological night, whereas other forms of strategic testing can identify conditions such as iatrogenic hypermelatoninemia. Routine testing in clinical practice can expand the range of identifiable circadian rhythm disorders.

Decreased need for sleep as an endophenotype of bipolar disorder: an actigraphy study.

Reports of subjective sleep impairments have been replicated in adults with bipolar disorder (BD), young BD patients, and even children of parents with BD. Furthermore, circadian rhythm alterations are a core feature of BD. Despite the impairment in circadian rhythms and altered sleep included in various heuristic developmental models of BD, thus far, biomarkers have not been sufficiently objectively validated. Thus, here, we assessed the rest-activity circadian rhythmicity and sleep macrostructure using actigraphy in a sample of unaffected child and adolescent offspring of bipolar parents (BO; n = 43; 21 females; 11.0 ± 3.2 years) and controls (n = 42; 17 females; 11.1 ± 3.4 years) comparable in sex (p = .4) and age (p = .7). All participants wore a MotionWatch 8 (Camntech, Cambridge, UK) actigraph on their nondominant wrist for ≥ 14 days and completed sleep diaries. Psychopathology was assessed by the Kiddie Schedule for Affective Disorders and Schizophrenia and by subjective scales. The main areas of interest were rest-activity circadian rhythmicity, chronotype and sleep macrostructure. Subgroup analyses (child and adolescent subgroups) were conducted to identify physiological differences in sleep between these age groups. The BO and controls did not differ in the presence of current mood (p = .5) and anxiety (p = .6) disorders. The BO had shorter sleep time on free days (p = .007; effect size, Cohen´s d = 0.56), lower sleep efficiency on free days (p = .01; d = 0.47), lower prolongation of time in bed on free days (p = .046; d = 0.41), and lower social jet lag (p = .04; d = 0.5) than the controls. A longer sleep time on school days (p < .001; d = 0.21), lower prolongation of sleep time between school and free days (p = .008; d = 0.74), and larger difference in sleep onset latency between school days and free days (p = .009; d = 0.52) were observed in the adolescent BO than in the controls. The child BO had poorer sleep quality on free days than the controls (p = .02; d = 0.96). In all cases, the results remained significant after controlling for subthreshold mood and anxiety symptoms. The BO had less variable rest-activity rhythm than controls (p = .04; d = 0.32). No other significant differences between the BO and controls were observed in the rest-activity circadian rhythmicity and chronotype. The results showed decreased physiological catch-up sleep on free days in the BO, which may indicate a decreased need for sleep in this population. Thus, the decreased need for sleep observed in the unaffected BO may represent an endophenotype of BD.

APOE ɛ4 and REM Sleep Behavior Disorder as Risk Factors for Sundown Syndrome in Alzheimer's Disease.

BACKGROUND: Sundown syndrome (SS) in patients with Alzheimer's disease (AD) is characterized by aggravation of behavioral problems at sunset. Disturbance of the circadian rhythm, a possible cause of SS, also facilitates amyloidopathy and reduces sleep quality. However, the associations of SS with amyloidopathy and sleep quality remain unclear. OBJECTIVE: To investigate the prevalence of SS in patients with AD, the association between SS and APOEɛ4 carrier, representing an enhanced amyloid pathology, and the relationship between SS and sleep quality in AD. METHODS: We included 104 patients with late-onset AD and known APOE genotype. All participants underwent a structured interview via informant-based questionnaires to assess sleep quality and the presence of SS. Binary logistic regression analysis was performed to determine odds ratios (ORs) of APOEɛ4 carrier and parameters of sleep quality for SS. RESULTS: The prevalence of SS in AD was 27.8% (n = 29). Patients with SS were significantly more likely to be APOEɛ4 carriers and to have rapid eye movement sleep behavior disorder (RBD) and a higher Clinical Dementia Rating (CDR) score compared to those without SS. In the multivariate regression analysis, APOEɛ4 carrier (OR 3.158, CI 1.022-9.758), RBD (OR 2.166, CI 1.073-4.371), and higher CDR score (OR 2.453, CI 1.084-5.550) were associated with an increased risk of SS. CONCLUSION: The prevalence of SS in patients with AD was 27.8%. The presence of the APOEɛ4 allele, RBD, and more severe dementia are associated with an increased risk of SS in AD.

Validation of a touchscreen psychomotor vigilance task.

OBJECTIVE: The purpose of this study was to compare a psychomotor vigilance task developed for use on touchscreen devices with the original PVT-192 in conditions of acute sleep loss and circadian desynchronization. BACKGROUND: The Psychomotor Vigilance Task (PVT) is considered the gold standard fatigue detection test and is used frequently in fatigue research. With the rapid development of new technologies it is essential to develop a PVT available on different platforms such as touchscreen devices. The advantage of such PVT is that it can be implemented on small devices and can be easily used in field studies. METHODS: Ten participants completed a 5-min PVT (NASA-PVT) on a touchscreen device and a 5-min PVT on the original PVT-192. On the day of the experiment, participants arrived in the lab approximately two hours after their habitual wake time. Participants completed a constant routine protocol under dim lighting, while maintaining a constant posture. The 5-min PVT-192 and NASA-PVT were taken every two hours for at least 24h. RESULTS: The NASA-PVT and PVT-192 were sensitive to extended wakefulness in the same manner. The reaction times were slower and the lapses were higher as time progressed on both NASA-PVT and PVT-192 (p<0.001). Overall, there was a sharp decline in performance after 16h of being awake which coincided with the time the participants were usually going to bed and the worst performance occurred after 24h of wakefulness for both PVTs (p<0.001). CONCLUSIONS: Overall, our data suggest that the NASA-PVT is a valid tool for assessing fatigue in field studies.

Sleep Disorders.

Sleep disorders are frequent and can have serious consequences on patients' health and quality of life. While some sleep disorders are more challenging to treat, most can be easily managed with adequate interventions. We review the main diagnostic features of 6 major sleep disorders (insomnia, circadian rhythm disorders, sleep-disordered breathing, hypersomnia/narcolepsy, parasomnias, and restless legs syndrome/periodic limb movement disorder) to aid medical practitioners in screening and treating sleep disorders as part of clinical practice.

Rest-activity rhythm profiles associated with manic-hypomanic and depressive symptoms.

Rest-activity rhythm (RAR) disturbances are associated with mood disorders. But there remains a need to identify the particular RAR profiles associated with psychiatric symptom dimensions. Establishing such profiles would support the development of tools that track the 24-h sleep-wake phenotypes signaling clinical heterogeneity. We used data-driven clustering to identify RAR profiles in 145 adults aged 36-82 years (mean = 60, standard deviation = 9). Then we evaluated psychiatric symptom dimensions (including positive and negative affect, depressive, manic-hypomanic, panic-agoraphobic, and substance use symptoms) associated with these empirically-derived RAR profiles. Clustering identified three sub-groups characterized, on average, by: (1) earlier and more robust RARs ("earlier/robust," n = 55, 38%); (2) later and irregular RARs ("later/irregular," n = 31, 21%); and (3) later RARs and a narrower active period ("later/narrower," n = 59, 41%). Compared with the "earlier/robust" group: the "later/irregular" group had higher levels of lifetime manic-hypomanic symptoms (ß (standard error) = 0.80 (0.22) higher standardized symptom units, p = 0.0004) and lifetime depression symptoms (ß (standard error) = 0.73 (0.21) higher standardized symptom units, p = 0.0009); the "later/narrower" group had more lifetime depression symptoms (ß (standard error) = 0.48 (0.18) higher standardized symptom units, p = 0.0076). These associations persisted after adjustments for sleep continuity and duration, suggesting that RARs are distinct behavioral correlates of clinical heterogeneity. Longitudinal studies are needed to confirm whether RAR characteristics contribute to the risk of manic and/or depressive episodes, and whether they reflect the consequences of psychiatric disturbance (e.g., on quality of life or disability). Opportunities to monitor or intervene on objectively-assessed RARs could facilitate better mental health related outcomes.

An overview of sleep and circadian dysfunction in Parkinson's disease.

Sleep and circadian alterations are amongst the very first symptoms experienced in Parkinson's disease, and sleep alterations are present in the majority of patients with overt clinical manifestation of Parkinson's disease. However, the magnitude of sleep and circadian dysfunction in Parkinson's disease, and its influence on the pathophysiology of Parkinson's disease remains often unclear and a matter of debate. In particular, the confounding influences of dopaminergic therapy on sleep and circadian dysfunction are a major challenge, and need to be more carefully addressed in clinical studies. The scope of this narrative review is to summarise the current knowledge around both sleep and circadian alterations in Parkinson's disease. We provide an overview on the frequency of excessive daytime sleepiness, insomnia, restless legs, obstructive apnea and nocturia in Parkinson's disease, as well as addressing sleep structure, rapid eye movement sleep behaviour disorder and circadian features in Parkinson's disease. Sleep and circadian disorders have been linked to pathological conditions that are often co-morbid in Parkinson's disease, including cognitive decline, memory impairment and neurodegeneration. Therefore, targeting sleep and circadian alterations could be one of the earliest and most promising opportunities to slow disease progression. We hope that this review will contribute to advance the discussion and inform new research efforts to progress our knowledge in this field.

Exploratory and Confirmatory Factor Analyses of Delirium Symptoms in a Sample of Nursing Home Residents.

OBJECTIVE: This study examined the latent constructs of delirium symptoms among nursing home (NH) residents in the United States. METHOD: Cross-sectional NH assessment data (Minimum Data Set 2.0) from the 2009 Medicare Current Beneficiary Survey were used. Data from two independent, randomly selected subsamples of residents ≥65 years were analyzed using exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). RESULTS: There were 367 and 366 individuals in the EFA and CFA, respectively. Assessment of multiple model fit statistics in CFA indicated that the two-factor structure provided better fit for the data than a one-factor solution. The two factors represented cognitive and behavioral latent constructs as suggested by the related literature. A correlation of .72 between these constructs suggested moderate discriminant validity. CONCLUSION: This finding emphasizes the importance of health care providers to be attentive to both cognitive and behavioral symptoms when diagnosing, treating, and managing delirium.

Chronic Insomnia Disorder.

PURPOSE OF REVIEW: Neurologists, along with all health care providers, commonly encounter patients with insomnia, which is a condition that impacts patients' underlying neurologic conditions in a bidirectional manner. While chronic insomnia is one of the most common sleep disturbances, only a small proportion of individuals with this condition discuss their sleep problems with their providers. When insomnia is described, it is more often in relationship to another medical problem, as opposed to an independent condition. In neurology practice, multiple factors including pain, movement disorders, sleep apnea, and medications that act on the central nervous system often contribute to insomnia. An all-inclusive approach is necessary when evaluating sleep problems in patients with insomnia. RECENT FINDINGS: The US Food and Drug Administration (FDA) has approved several medications for the treatment of insomnia that target specific receptor systems in the brain and incorporate several unique pharmacodynamic and pharmacokinetic profiles that can represent customized therapy for specific insomnia phenotypes. FDA-approved medications for insomnia include γ-aminobutyric acid (GABA)-modulating benzodiazepine receptor agonists, a melatonin receptor agonist, a histamine receptor antagonist, and the newest approved option, a hypocretin (orexin) receptor antagonist. SUMMARY: This article provides an evidence-based multidisciplinary approach to the treatment of insomnia, highlighting the rationale and utility of cognitive-behavioral therapy and pharmacologic interventions. Neurologists should be proactive in assessing the impact of underlying comorbidities on insomnia, particularly in the setting of psychiatric conditions such as depression, sleep disorders such as circadian rhythm disorders, and medical problems such as nocturia.

Biological dysrhythm in remitted bipolar I disorder.

BACKGROUND: Recent treatment guidelines support treatment of biological rhythm abnormalities as a part of treatment of bipolar disorder, but still, literature examining various domains (Sleep, Activity, Social, and Eating) of biological rhythm and its clinical predictors are less. OBJECTIVES: The main aim of our study is to compare various domains of biological rhythm among remitted bipolar I subjects and healthy controls. We also explored for any association between clinical variables and biological rhythm among bipolar subjects. METHODS: 40 subjects with Bipolar I disorder and 40 healthy controls who met inclusion and exclusion criteria were recruited for the study. Diagnoses were ascertained by a qualified psychiatrist using MINI 5.0. Sociodemographic details, biological rhythm (BRIAN-Biological Rhythm Interview of assessment in Neuropsychiatry) and Sleep functioning (PSQI- Pittsburgh Sleep Quality Index) were assessed in all subjects. RESULTS: Mean age of the Bipolar subjects and controls were 41.25±11.84years and 38.25±11.25 years respectively. Bipolar subjects experienced more biological rhythm disturbance when compared to healthy controls (total BRIAN score being 34.25±9.36 vs 28.2±6.53) (p=0.002). Subsyndromal depressive symptoms (HDRS) had significant positive correlation with BRIAN global scores(r=0.368, p=0.02). Linear regression analysis showed that number of episodes which required hospitalization (ß=0.601, t=3.106, P=0.004), PSQI (ß=0.394, t=2.609, p=0.014), HDRS (ß=0.376, t=2.34, t=0.036) explained 31% of variance in BRIAN scores in remitted bipolar subjects. CONCLUSION: Biological rhythm disturbances seem to persist even after clinical remission of bipolar illness. More studies to look into the impact of subsyndromal depressive symptoms on biological rhythm are needed.

Comparative validity of the Internet and paper-and-pencil versions of the Night Eating Questionnaire.

OBJECTIVE: This study examined the psychometric properties of the Internet and paper-and-pencil versions of the Mandarin Chinese version of the Night Eating Questionnaire (C-NEQ) and compared these measures' validity. METHOD: The C-NEQ was evaluated through two different media: 626 participants completed the C-NEQ on the Internet and 160 participants completed the paper-form C-NEQ at the psychiatric outpatient clinics. A subgroup completed both versions of the C-NEQ (n=50). The Night Eating Syndrome History and Inventory was used to identify individuals with night eating syndrome (NES). RESULTS: The paper-and-pencil and Internet versions of the C-NEQ both showed good internal consistency, reliability, and concurrent validity. Reliability between the Internet and the paper-and-pencil versions of the C-NEQ was excellent (ICC=.96). Diagnostic analysis of the C-NEQ's performance using the Receiver Operation Curve method showed excellent results in both versions; the area under the curve did not differ significantly between the versions. Regarding detecting NES, the Internet version had a higher optimal cutoff point than the paper-and-pencil version (23 and 22, respectively). CONCLUSIONS: The Internet and paper-and-pencil versions of the C-NEQ both showed strong reliability and validity; however the two versions appear to differ marginally regarding usage in NES detection.

Dynamic light application therapy to reduce the incidence and duration of delirium in intensive-care patients: a randomised controlled trial.

BACKGROUND: Disturbed circadian rhythm is a potentially modifiable cause of delirium among patients in intensive-care units (ICUs). Bright-light therapy in the daytime can realign circadian rhythm and reduce the incidence of delirium. We investigated whether a high-intensity dynamic light application (DLA) would reduce ICU-acquired delirium. METHODS: This was a randomised, controlled, single-centre trial of medical and surgical patients admitted to the ICU of a teaching hospital in the Netherlands. Patients older than 18 years, expected to stay in the ICU longer than 24 h and who could be assessed for delirium were randomised to DLA or normal lighting (control), according to a computer-generated schedule. The DLA was administered through ceiling-mounted fluorescent tubes that delivered bluish-white light up to 1700 lux between 0900 h and 1600 h, except for 1130-1330 h, when the light was dimmed to 300 lux. The light could only be turned off centrally by investigators. Control light levels were 300 lux and lights could be turned on and off from inside the room. The primary endpoint was the cumulative incidence of ICU-acquired delirium. Analyses were by intention to treat and per protocol. The study was terminated prematurely after an interim analysis for futility. This study is registered with Clinicaltrials.gov, number NCT01274819. FINDINGS: Between July 1, 2011, and Sept 9, 2013, 734 patients were enrolled, 361 in the DLA group and 373 in the control group. Delirium occurred in 137 (38%) of 361 DLA patients and 123 (33%) of 373 control patients (odds ratio 1·24, 95% CI 0·92-1·68, p=0·16). No adverse events were noted in patients or staff. INTERPRETATION: DLA as a single intervention does not reduce the cumulative incidence of delirium. Bright-light therapy should be assessed as part of a multicomponent strategy. FUNDING: None.

A Study of Biological Rhythm Disturbances in Polish Remitted Bipolar Patients using the BRIAN, CSM, and SWPAQ Scales.

BACKGROUND/AIMS: The Biological Rhythms Interview of Assessment in Neuropsychiatry (BRIAN) is a novel tool allowing for a complex assessment of biological rhythms. We compared patients with bipolar disorder (BD) and healthy control subjects (HC) using the Polish version of the BRIAN scale. METHOD: Fifty-four remitted BD patients (17 males and 37 females aged 52 ± 13 years) and 54 healthy control subjects (25 males and 29 females aged 42 ± 14 years) were studied. In addition to the BRIAN scale, the Composite Scale of Morningness (CSM) and the Sleep-Wake Pattern Assessment Questionnaire (SWPAQ) were employed. RESULTS: The Polish version of the BRIAN scale displayed high feasibility and consistency, showing that the patients had greater biological rhythm disturbances than the controls. After regression analysis, significant differences were obtained for the BRIAN subscales activity and predominant chronotype, and for the SWPAQ items quality of night-time sleep and ability to stay awake. We obtained positive correlations between higher BRIAN scores and morningness and eveningness, but the correlations with vigilance and the ability to stay awake (on the SWPAQ) were negative. CONCLUSIONS: Using the BRIAN scale, we confirmed the greater disturbances of biological rhythm in Polish remitted bipolar patients, compared with healthy controls. The differences between these 2 groups in sleep-awake patterns were also demonstrated by the SWPAQ scores. In contrast to other studies, we were unable to confirm an evening chronotype as a discriminating factor between remitted bipolar patients and healthy subjects. This can be explained by the older age and the use of lithium by a significant proportion of the patients.

The Clinical Usefulness of Sleep Studies in Children.

Sleep disordered breathing is common in children and has the potential to have a significant impact on cognition, activity and social interaction. The overnight in-laboratory polysomnography (PSG) continues to be the gold standard instrument for the investigation of sleep-disordered breathing in children. It has the ability to rule in or rule out the need for intervention for common conditions such as obstructive sleep apnoea, assess the role of sleep quality in children and adolescents with hypersomnolence, provide physiologic data in children with hypoventilation as may be seen in neuromuscular disease and assist in the assessment of children with structural airway and lung abnormalities. Polysomnography is valuable and the only reliable method to differentiate habitual snoring from many levels of sleep apnoea syndrome [1]. The American Academy of Paediatrics recommends that, in order to diagnose and manage OSA syndrome, all children should be screened for snoring and complex cases should be referred to a specialist. PSG is the diagnostic gold standard and adenotonsillectomy is the first line of treatment [2]. There is no evidence to support nap studies or ambulatory sleep studies in children [3]. With adequate staffing, expertise, and a child and family-friendly environment, children of any age can undergo a sleep study.