Analysis of postarousal EEG activity during somnambulistic episodes

Early studies found that electroencephalographic (EEG) recordings during somnambulistic episodes were characterized by a combination of alpha, theta, and delta frequencies, without evidence of clear wakefulness. Three postarousal EEG patterns associated with slow-wave sleep (SWS) arousals were recently identified in adults with sleepwalking and sleep terrors. The goal of the present study was to evaluate the distribution of these postarousal EEG patterns in 10 somnambulistic patients (three males, seven females, mean age: 25.1, SD: 4.1) evaluated at baseline and following 38 h of sleep deprivation. A total of 44 behavioral arousals were recorded in the laboratory; seven episodes at baseline (five from SWS, two from stage 2 sleep) and 37 episodes during recovery sleep (30 from SWS, seven from stage 2 sleep). There was no significant difference in the distribution of postarousal EEG patterns identified during baseline and recovery sleep. One pattern, comprised of diffuse rhythmic and synchronous delta activity, was preferentially associated with relatively simple behavioral episodes but did not occur during episodes from stage 2 sleep. Overall, delta activity was detected in 48% of the behavioral episodes from SWS and in 22% of those from stage 2. There was no evidence of complete awakening during any of the episodes. The results support the view of somnambulism as a disorder of arousal and suggest that sleepwalkers' atypical arousal reactions can manifest themselves in stage 2 sleep in addition to SWS.     

EEG delta power during sleep in young and old rats

Delta EEG power density, which has been viewed as a measure of intensity of NREM sleep, declines across the lifetime in humans, cats, and hamsters, but data in rats have been unclear. It is also uncertain whether older rats differ from younger animals in the degree of change in delta power during recovery sleep following short-term sleep deprivation. We have examined delta power density in NREM sleep under baseline conditions and following 48 h of sleep deprivation in young (3 months), middle-aged (12 months), and older (24 months) rats. The presence or absence of age effects was highly dependent on the method of normalizing the data. When expressed as a fraction of total NREM EEG power, there was no age effect on baseline delta power density, or on the change from baseline to recovery conditions. When expressed as a multiple of delta power in REM under the same condition, the younger rats had higher delta power density than the middle-aged and older rats. For all the ages combined, there was an increase in delta power density in the recovery condition. When examined by age, the younger rats (which started from a higher level of delta power density than the other groups) did not have an increase in delta during recovery; the middle-aged rats tended to, and the older rats (which started from lower baseline levels) significantly increased delta power density in the recovery condition. This suggests that the lower delta power seen during baseline in older rats is not due to decreased ability to generate delta activity.     

Sleep bruxism based on self-report in a nationwide twin cohort

The relative roles of genetic and environmental factors in bruxism are not known. In 1990 a questionnaire sent to the Finnish Twin Cohort yielded responses from 1298 monozygotic and 2419 dizygotic twin pairs aged 33–60 years. We used structural equation modelling to estimate genetic and environmental components of variance in the liability to bruxism. There was a significant gender difference both in childhood (P =0.001) and adult (P =0.007) bruxism. Females compared to males reported childhood bruxism ‘often’ 5.2% vs 4.1% and ‘sometimes’ 17.4% vs 17.3%, and as adults ‘weekly’ 3.7% vs 3.8% and ‘monthly’ 3.9% vs 4.6%, respectively. Bruxism in childhood and adulthood is highly correlated (0.86 in males and 0.87 in females). The proportion of total phenotypic variance in liability to bruxism attributed to genetic influences in childhood bruxism was 49% (95% CI 37–60%) in males and 64% (55–71%) in females, and for adults 39% (27–50%) among males and 53% (44–62%) among females. The correlation between the genetic effects on childhood bruxism and the genetic effects on adult bruxism was estimated in a bivariate model to be 0.95 (95% CI 0.94–0.96) in males and 0.89 (0.88–0.90) in females. Bruxism appears to be quite a persistent trait. There are substantial genetic effects on bruxism both in childhood and as adults, which appear to be highly correlated.     

Age-related changes in cardiac autonomic control during sleep

Aging is commonly associated with decreased sleep quality and increased periodic breathing (PB) that can influence heart rate variability (HRV). Cardiac autonomic control, as inferred from HRV analysis, was determined, taking into account the sleep quality and breathing patterns. Two groups of 12 young (21.1 +/- 0.8 years) and 12 older (64.9 +/- 1.9 years) volunteers underwent electroencephalographic, cardiac, and respiratory recordings during one experimental night. Time and frequency domain indices of HRV were calculated in 5-min segments, together with electroencephalographic and respiratory power spectra. In the elderly, large R-R oscillations in the very-low frequency (VLF) range emerged, that reflected the frequency of PB observed in 18% of the sleep time. PB occurred more frequently during rapid eye movement sleep (REM) sleep and caused a significant (P < 0.02) increase in the standard deviation of normal R-R intervals (SDNN) and absolute low-frequency (LF) power. With normal respiratory patterns, SDNN, absolute VLF, LF, and high frequency (HF) power fell during each sleep stage (P < 0.01) compared with young subjects, with no significant sleep-stage dependent variations. An overall decrease (P < 0.01) in normalized HF/(LF + HF) was observed in the elderly, suggesting a predominant loss of parasympathetic activity which may be related to decreased slow-wave sleep duration. These results indicate that two distinct breathing features, implying different levels of autonomic drive to the heart, influence HRV in the elderly during sleep. The breathing pattern must be considered to correctly interpret HRV in the elderly.     

慢性不完全性睡眠剥夺对幼鼠学习记忆的影响

目的：探讨慢性不完全性睡眠剥夺对幼鼠学习记忆能力的影响及其可能机制。方法：建立慢性不完全性睡眠剥夺动物模型，并测定其空间学习记忆能力，同时对幼鼠大脑前额皮质及海马神经元性一氧化氮合酶(nNOS)的表达进行分析。结果：睡眠剥夺组幼鼠完成预定任务所需的时间及发生错误的次数均超过正常对照组。睡眠剥夺组的nNOS在前额皮质区域阳性、强阳性表达面积及在海马区域强阳性表达面积均大于正常对照组。结论：慢性不完全性睡眠剥夺会影响幼鼠的学习记忆能力，而前额皮质及海马中nNOS表达水平的下降可能是慢性不完全性睡眠剥夺影响未成熟脑学习记忆能力的机制之一。     

睡眠信念与态度量表在失眠患者健康教育中的应用

目的: 采用睡眠个人信念与态度量表探索患者睡眠障碍与哪些歪曲的信念有关,针对歪曲的信念进行睡眠实践教育,达到促进睡眠的目的.方法: 连续收集62例以失眠为主诉的患者,随机分成试验组与对照组,各31例,两组均在药物治疗及心理治疗基础上进行睡眠健康教育.试验组针对患者自身存在的歪曲信念态度进行健康教育,而对照组只进行常规的健康宣教.入组前及入组后每周,应用睡眠个人信念与态度量表(Dysfunctional Beliefs and Attitudes about Sleep Scale,DBAS)、匹茨堡睡眠指数量表(Pittsburgh Sleep Quality Index,PSQI)对两组进行测评,同时让患者评价睡眠时间、睡眠质量、睡眠效果和对健康教育接受程度.结果: 健康教育4周后试验组和对照组DBAS得分均高于人组时[(111.0±8.7)vs.(88.9±12.3)、(93.5±17.2)vs.(81.3±19.2),P:0.001、0.010],而PSQI得分均低于入组时[(5.5±2.1)vs.(10.9±4.4)、(9.0 ±2.1)vs.(11.5±3.6),均P=0.001];健康教育4周后对照组的DBAS得分低于实验组,而PSQI得分高于实验组.健康教育后试验组对睡眠时间、睡眠质量、睡眠效果满意的比例均明显提高,睡眠时间满意的比例由18/31到30/31,对睡眠质量满意比例由8/31变为23/31,对睡眠效果满意比例由8/31到21/31(均P＜0.05).试验组对睡眠时间满意的比例明显高于对照组(30/31 vs.14/31,P＜0.01),对健康教育的接受程度也明显高于对照组(18/31 vs.5/31,P＜0.05).结论: 试验组健康教育后患者的睡眠信念有了明显的改善,睡眠质量有了提高.     

Evolution of sleep and sleep EEG after hemispheric stroke

The evolution of subjective sleep and sleep electroencephalogram (EEG) after hemispheric stroke have been rarely studied and the relationship of sleep variables to stroke outcome is essentially unknown. We studied 27 patients with first hemispheric ischaemic stroke and no sleep apnoea in the acute (1-8 days), subacute (9-35 days), and chronic phase (5-24 months) after stroke. Clinical assessment included estimated sleep time per 24 h (EST) and Epworth sleepiness score (ESS) before stroke, as well as EST, ESS and clinical outcome after stroke. Sleep EEG data from stroke patients were compared with data from 11 hospitalized controls and published norms. Changes in EST (>2 h, 38% of patients) and ESS (>3 points, 26%) were frequent but correlated poorly with sleep EEG changes. In the chronic phase no significant differences in sleep EEG between controls and patients were found. High sleep efficiency and low wakefulness after sleep onset in the acute phase were associated with a good long-term outcome. These two sleep EEG variables improved significantly from the acute to the subacute and chronic phase. In conclusion, hemispheric strokes can cause insomnia, hypersomnia or changes in sleep needs but only rarely persisting sleep EEG abnormalities. High sleep EEG continuity in the acute phase of stroke heralds a good clinical outcome.     

REM sleep deprivation increases preference for novelty in rats.

As a further test of the hypothesis that REM deprivation decreases fear, the behavior of 40 male rats was measured in a Y-maze adapted to test for preference for novelty. Prior to this test, the animals were exposed for 4 days to one of four treatments, i.e., either a dry environment control, a wet environment control, a 2-day REM deprivation period or a 4-day REM deprivation period. During the test both number of grid crossing in the novel and non-novel arms of the Y-maze and three indices of emotionality were recorded. The results were congruent with data we had reported earlier and offered convincing evidence in support of the hypothesis.     

正常成人上呼吸道CT测量及其意义

目的：确定正常人的上呼吸道CT扫描下各平面的横截面积、经线长度以及咽壁厚度，为临床服务。方法：无明显睡眠呼吸疾病史的成年人（男115、女110），采用Philips Tomoscan AV Expander E1螺旋CT，对鼻咽顶部到声门之间的区域进行连续扫描，测量软腭后区、悬雍垂后区、舌后区和会厌后区的气道横截面积、失状径、冠状径、咽侧壁和咽后壁软组织厚度，以单侧95％可信区间确定各测量指标的参考值。结果：在上呼吸道各个扫描平面，绝大多数气道的形状均为横椭圆形，冠状径大于失状径，在软腭后区、悬雍垂后区、舌后区和会厌后区中，失状径大于冠状径者分别占总人数的3．11％、10．67％、0．8％和0％。各年龄组间比较，绝大多数测量指标差异不显著，男子组和女子组间比较，除软腭后区外，大多数测量指标差异显著。故分别制定了男、女各测量指标的还范围。结论：成人上呼吸道CT测量以及正常范围的确定为临床判定OSAS患者上呼吸道解剖性狭窄的部位提供了客观依据，男性OSAS发病率明显高于女性有其相关的生理基础。     

Blood pressure analysis

SUMMARY  Arterial blood pressure is influenced by sleep-related breathing disorders. As cardiovascular consequences can be diagnosed by an accurate recording and analysis of blood pressure, new recording methodologies and an approach to analysis are presented here. Invasive continuous blood pressure recording is the common reference for all methodologies. As blood pressure varies rapidly in parallel with sleep-related breathing disorders it is indispensible to record blood pressure continuously. To introduce non-invasive methodology the Finapres system was used during sleep studies; a validation study showed severe limitations. This study was followed by the validation of an improved system called Portapres, which is portable, has two finger cuffs and a hydrostatic height compensation.
Analysis of continuous blood pressure in patients with sleep apnoea is carried out to detect mechanisms which influence the cardiovascular risk. Spectrum analysis of systolic blood pressure showed two different major oscillations present in patients with obstructive sleep apnoea. One oscillation (<0.06 Hz) occurs in parallel with each apnoeic episode and the other oscillation (0.2-0.4 Hz) occurs in parallel with the obstructive efforts during each apnoea and in parallel with respiration during periods of snoring. These two oscillations were so specific that the use of non-invasive continuous blood pressure recording allowed an estimation of the extent of underlying breathing disorders, and assessment of cardiovascular risk in a patient with obstructive apnoea in terms of hypertension and on the basis of ambulatory monitoring.