Correlation dimension of the human sleep electroencephalogram

Sleep electroencephalogram (EEG) was analyzed by nonlinear analysis. Polysomnography of a healthy male subject was analyzed and the correlation dimension was calculated. The mean correlation dimensions decreased from stage 'awake' to stages 1, 2 and 3, and increased during rapid eye movement (REM) sleep. These results were also seen at every sleep cycle. During each sleep cycle the correlation dimensions decreased for slow wave sleep, then increased for REM sleep. The mean correlation dimension of the sleep EEG in the second half of the night was significantly higher than those in the first half of the night. A significant change was seen both during REM sleep as well as in sleep stage 2. Nonlinear analysis may be a useful method in the analysis of the entire sleep electroencephalogram.     

Nocturnal sleep spindle activity in blind subjects

To determine spindle activity during sleep in congenitally blind subjects, electroencephalogram sleep recordings were done on two or three consecutive nights in five subjects aged in their 20s and 30s. The number per minute and the duration of sleep spindles, scored visually, were compared with the data of sighted persons of comparable ages. The results indicated that the total number of sleep spindles a night was ranged from 117 to 585, and the number per minute ranged 0.52 to 2.06 during stage 2. Both values were much less than the values of sighted persons.     

无抽搐电休克治疗对男性抑郁症病人多导睡眠图的影响

目的:探讨无抽搐电休克(MECT)治疗对抑郁症病人睡眠脑电活动的影响。方法:应用多导睡眠图(PSG)对12例男性首发抑郁症病人在MECT治疗前后进行整夜PSG记录,观察MECT治疗前后PSG的变化。结果:与正常对照组比较,病人组睡眠总时间减少、睡眠潜伏期延迟、觉醒增加、快动眼睡眠(REM)时间增多、REM潜伏期缩短、S1和S2增加以及慢波睡眠减少。病人组经过MECT治疗后PSG显示睡眠总时间增加[治疗前:(342±s51)min,治疗后:(437±25)min,t值11.840,P<0.01],睡眠潜伏期缩短[治疗前:(68±12)min,治疗后:(56±7)min,t值4.249,P<0.01],觉醒时间减少[治疗前:(163±43)min,治疗后:(30±7)min,t值10.409,P<0.01],REM睡眠时间减少[治疗前:(164±19)min,治疗后:(120±5)min,t值9.333,P<0.01],S1减少[治疗前:(46±15)min,治疗后:(39±11)min,t值5.071,P<0.01],慢波睡眠增加[治疗前:(34±19)min,治疗后:(99±7)min,t值-13.146,P<0.01]。REM潜伏期和S2未见明显变化(P>0.05)。结论:MECT有改善睡眠的作用。这可能是MECT起到治疗抑郁症的重要机制之一。     

Analysis of automated quantification of motor activity in REM sleep behaviour disorder

Rapid eye movement (REM) sleep behaviour disorder (RBD) is characterized by dream enactment and REM sleep without atonia. Atonia is evaluated on the basis of visual criteria, but there is a need for more objective, quantitative measurements. We aimed to define and optimize a method for establishing baseline and all other parameters in automatic quantifying submental motor activity during REM sleep. We analysed the electromyographic activity of the submental muscle in polysomnographs of 29 patients with idiopathic RBD (iRBD), 29 controls and 43 Parkinson's (PD) patients. Six adjustable parameters for motor activity were defined. Motor activity was detected and quantified automatically. The optimal parameters for separating RBD patients from controls were investigated by identifying the greatest area under the receiver operating curve from a total of 648 possible combinations. The optimal parameters were validated on PD patients. Automatic baseline estimation improved characterization of atonia during REM sleep, as it eliminates inter/intra‐observer variability and can be standardized across diagnostic centres. We found an optimized method for quantifying motor activity during REM sleep. The method was stable and can be used to differentiate RBD from controls and to quantify motor activity during REM sleep in patients with neurodegeneration. No control had more than 30% of REM sleep with increased motor activity; patients with known RBD had as low activity as 4.5%. We developed and applied a sensitive, quantitative, automatic algorithm to evaluate loss of atonia in RBD patients.     

Insomnia and incident depression: role of objective sleep duration and natural history

Longitudinal studies that have examined the association of insomnia with incident depression using objective sleep measures are very limited. The aim of this study was to examine the predictive role of the severity of insomnia for incident depression in a general population sample using psychometric and polysomnographic data. From a random, general population sample of 1741 individuals of the Penn State Adult Cohort, 1137 adults without depression were followed up with a structured telephone interview after 7.5 years. All subjects completed a full medical evaluation, 1‐night polysomnogram and Multiphasic Minnesota Personality Inventory at baseline. The incidence of depression was 15%. Poor sleep (odds ratio = 1.5, P = 0.001) and insomnia (odds ratio = 1.9, P = 0.031) were significantly associated with incident depression. The odds of incident depression were highest (odds ratio = 2.2, P = 0.019) in insomnia with objective short sleep duration and independent of Multiphasic Minnesota Personality Inventory Ego Strength scores, an index of poor coping resources. The persistence of insomnia and worsening of poor sleep into insomnia significantly increased the odds of incident depression (odds ratios ranged from 1.8 to 6.3), whereas their full remission did not (odds ratio ranged from 1.2 to 1.8). Insomnia with short sleep duration is associated with incident depression independent of poor coping resources, whereas the association of insomnia with normal sleep duration with incident depression was mediated by poor coping resources. Persistence and worsening of poor sleep or insomnia, but not their full remission, are significant predictors of incident depression. These data suggest that there is a significant relationship between the severity of insomnia and incident depression.     

Prevalence of pulmonary embolism in patients with obstructive sleep apnea and chronic obstructive pulmonary disease: The overlap syndrome

ObjectiveGrowing evidence indicates that both obstructive sleep apnea (OSA) and chronic obstructive pulmonary disease (COPD) may be closely associated with the prevalence of pulmonary embolism (PE). However, the relationship of overlap syndrome (OS) (coexistence of OSA and COPD) with PE is unclear. The purpose of this study was to investigate whether OS were associated with increased PE prevalence.MethodsWe performed a retrospective chart review of patients who underwent sleep study at Beijing An Zhen Hospital from 2011 to 2014. The association of OS with PE prevalence was estimated by using logistic regression models.ResultsIn contrast to control patients (neither OSA nor COPD), those subjects with OS had higher odds of PE (OR9.61; 95%CI 4.02–21.31, p < 0.001) with significance persisting after adjusting for covariates (OR 5.66; 95%CI 1.80–16.18, p = 0.004). Meanwhile, patients with OS compared with those with isolated OSA also had significantly higher odds of PE in univariate (OR 4.79; 95%CI 2.04–10.33, p = 0.0007) and adjusted models (OR 3.89; 95%CI 1.27–10.68, p = 0.019). In subgroup analysis, patients with OS had higher odds of PE than control group among male subjects (OR 8.12, 95%CI1.86–31.87, p = 0.007) and patients ≥ 58years (OR 5.50, 95%CI 1.51–18.14, p = 0.012) in multivariable models. Percentage of total sleep time with saturation lower than 90% (T90) ≥ 2.6% was significantly associated with prevalence of PE (OR 4.72, 95%CI1.34–19.83, p = 0.015) in subgroup of patients older than 58.ConclusionsOS is independently associated with PE prevalence. Longitudinal studies are needed to better understand the relationship with incident PE.     

Predicting the presence and severity of obstructive sleep apnea based on mandibular measurements using quantitative analysis of facial profiles via three-dimensional photogrammetry

BackgroundIn obstructive sleep apnea (OSA), the upper airway is obstructed during sleep due to obesity and/or posterior collapse of the tongue root. Maxillofacial morphological abnormalities increase the risk of OSA in the Asian population. This study sought to elucidate whether three-dimensional (3D) photogrammetry measurements correlate with the severity of OSA irrespective of sex and degree of obesity.MethodsA prospective pilot study was performed, in which 37 consecutive adult patients (M/F = 28/9) underwent polysomnography and 3D photogrammetry in the supine position for the diagnosis of OSA. Measurements obtained from 3D photogrammetry included mandibular width (Mw), mandibular length (Ml), mandibular depth (Md), mandibular width–length angle (Mwla), and mandibular area (Ma). The effects of sex and body mass index (BMI) on the measurements and their association with the apnea–hypopnea index (AHI) were statistically analyzed. The inter-rater reliability of the measurements was evaluated using intraclass correlation coefficients (ICC).ResultsMwla (R = 0.73, p < 0.01), Mw (R = 0.39, p < 0.05), and Md (R = ?0.34, p < 0.05) were significantly correlated with the severity of OSA. On multivariate analysis, Mwla (p < 0.01) and Md (p < 0.05) remained independent factors for AHI after adjusting for sex, age, BMI, and neck circumference. In addition, diagnosability analysis revealed that Mwla was useful for identifying the presence of OSA (AHI ≥5) (cutoff: 78.6°, sensitivity: 0.938, specificity: 0.800, area under the curve: 0.931). The ICC was >0.9, showing high reliability.ConclusionsThis study suggests that Mwla measured using 3D photogrammetry can predict the presence of OSA and correlates with the severity of OSA, independent of obesity and sex.