右胸电导纳容积波法估测肺动脉楔嵌压和左室舒张末压的实验研究

目的：进一步证实右胸电导纳容积波法估测肺动脉楔嵌压（PAWP）和左室舒张末压（LVEDP）的准确性,方法：选择健康杂种犬8只．用心导管术测定PAWP和LVEDP,分析右胸电导纳容积波参数与心导管测值的相关性．结果：PAWP与ha（a波高度）、ha／hz（hz=z波高度）的相关系数分别为0．83（P＜0．01）和0．81（P＜0．01）;LVEDP与hc（c波高度）、hc／hz的相关系数分别为0．75（P＜0．05）和0．83（P＜0．05）．结论：右胸电导纳容积波法是评价左心功能的一种无创方法．     

一种无创测定桡动脉脉搏波速度的方法及影响脉搏波速度的因素

提出了一种无创测定桡动脉脉搏波速度的有效方法．实验测定的结果表明,弦脉的脉搏波速度比同龄组平脉有显著性增大（P＜0．01或P＜0．05）,细脉的脉搏波速度比同龄组平脉有所减小（P＜0．05）,而滑脉与同龄组的平脉相比无显著性差异（P＞0．05）;脉搏波速度与动脉血压之间具有很大的相关性。最后结合临床诊断的意义分析和讨论了影响脉搏波速度的可能因素。     

脑导纳微分环流入相面积值的探讨

目的:本项研究的目的是探讨脑导纳微分环快流入相和慢流入相面积和对血管弹性判定的诊断价值.方法:应用深圳市辉大高科技发展有限公司研制和生产的HD-ENG导纳式双侧脑血流图自动检测仪对高血压患者进行脑导纳环检测,并与正常组比较.结果:研究结果显示高血压病患者的脑导纳微分环的流入相的面积与正常组有显著性差异;而高血压有动脉硬化和无动脉硬化患者之间却不存在显著性差异.     

血压波功率谱熵与年龄的关系

以10位年轻(21岁-34岁)与10位年老(68岁-81岁)的经过严格筛选的健康人为研究对象,同步记录每位受试者在仰卧时的血压波、心电图、呼吸波信号,计算出所有信号的功率谱熵.结果是:年轻组的血压波功率谱熵明显大于年老组(P＜0.01),而心电图与呼吸波的功率谱熵没有显著差异(P＞0.1).这一结果预示着血压波功率谱熵可作为心率波动的一种新的度量.     

伴学习困难注意缺陷多动障碍儿童α波竞争图特点

目的：探讨伴学习困难注意缺陷多动障碍（ADHD）儿童α波竞争图特点及其神经生理机制。方法：应用脑电超慢涨落分析技术，对90例不伴学习困难ADHD儿童和45例伴学习困难ADHD儿童的α波进行分析处理，比较两组的检测结果：结果：1．伴学习困难组8Hz优势几率明显高于不伴学习困难组，差异有显著性（t=-0.29,P=0.030)；2．伴学习困难组10hz优势几率明显低于不伴学习困难组，差异有显著性（t=2.16,P=0.032);3．伴学习困难组主频为9Hz,α波能量分布曲线左移、低平，而不伴学习困难组主频为10Hz,次频为9Hz;4．伴学习困难组各脑区熵值均高于不伴学习困难组，尤其在O2，T6导联，两组差异具有显著性（P＜0．05），结论：伴学习困难ADHD儿童α波竞争图特点是：α波慢化、认知参量10Hz明显减少、主频左移、脑有序度低。这些特点可能为ADHD儿童出现学习困难的神经生理基础。     

医用阻抗／导纳图呼吸波消除仪的研制

本文介绍以ＭＣＳ－５１系列单片机为基础的医用阻抗、导纳图呼吸波消除仪的研制。它采用ＣＰＵ并行处理结构，对反映血液循环状态的阻抗或导纳波进行动态处理，以消除呼吸波等生理干扰信号。该仪器具有模入、模出接口，可与各种医用阻抗仪及心脏功能检测仪配接。     

右胸电导纳容积波法估测肺动脉楔嵌压和左室舒张末？…

目的：进一步证实右胸电导纳容积波法估测肺动脉楔嵌压和左室舒张末压的准确性，方法；选择健康杂种犬８只，用心导管术测定ＰＡＷＰ和ＬＶＥＤＰ，分析右胸电导纳容积波参数与心导管测值的相关性。结果：ＰＡＷＰ与ｈａ（ａ波高度），ｈａ／ｈｚ（ｈｚ＝ｚ）波高度的相关系数分别为０．８３和０．８１ＬＶＥＤＰ与ｈｃ，ｈｃ／ｈｚ的相关系数分别为０．７５和０．８３。结论：右胸电导纳容积波法是评价左心功能的的一种无创方法。     

小鼠Ⅱ导联QRS波群功率谱与心率相关性的研究

本研究了正常小鼠组（n=20)和实验小鼠组（n=10)Ⅱ导联QRS波群功率谱与心率的相关性，发现正常小鼠组Ⅱ导联QRS波群中10^2-10^3Hz、80－300Hz的高频相对能量都与心率呈显正相关（P＜0．001）；实验小鼠组Ⅱ导联QRS波群中仅10^2-10^3Hz的高频相对能量与心率呈显正相关（P＜0．05）。     

老年慢性精神分裂症患者脑电地形图初步研究

目的：为探讨老年慢性精神分裂症患者（SCS）与正常老人在脑电地形图（BEAM）检查中的各自特点。方法：使用16道地形图仪，对39例正常老人和24例SCS患者的BEAM作了检测。结果：在头颅模式图中，SCS患者的BEAM趋向凹字形低密度带。在前颞区θ频域及枕区和中央区δ频域均右侧高于左侧（P＜0．05）。与正常老人相比，SCS患者δ与θ波功率在主要记录点均增高（P＜0．05或P＜0．01）。α波功率在F3、F4、P3、P4以及Fp1、F7记录点下降（P＜0．01或P＜0．05）。β波功率在主要记录点（Fp1、Fp2、T3、T4、T5、T6、O1、O2、F3、F4）上降低也有显著性差异（P＜0．05）。SCS患者BEAM－EEG比EEG提高阳性检出率12．5％。结论：SCS患者的BEAM－EEG具有不同于正常衰老的改变。     

P波离散度测定正常值的研究

目的 :测定 P波离散度 ( Pd)制定正常值范围。方法 :采用同步十二导联心电图机测定 10 0例健康成人和 3 0例有阵发性房颤病史患者的 P波离散度 ,测量 Pd正常值范围。结果 :心房颤动组 P波离散度增高 ( 4 7.8± 7.6ms) ,与健康成人 ( 2 0 .6± 10 .5 ms)差异有非常显著性意义 ( P<0 .0 1) ;Pd在男女性别及各年龄段之间差异无显著性 ( P>0 .0 5 )。结论 :P波离散度小于 40 ms为正常范围     

Characterization of arterial stenosis and elasticity by analysis of high-frequency pressure wave components

We describe a novel method for assessing stenosis severity based on pressure wave measurements. Pressure waves for several degrees of stenosis at different distances proximal to the stenosis were recorded from in vitro and in vivo models. Signal analysis was performed using power spectral density, and radial compliance was also measured. Pressure wave components at the acoustic frequency band (400-2500Hz) changed gradually and were dependent upon the distance from the stenosis and its severity. The shift of the pressure components could also demonstrate the elastic properties of tubes and arteries and explain the effect of a bifurcation in the system.     

Electroencephalogram power density and slow wave sleep as a function of prior waking and circadian phase

Human sleep electroencephalograms, recorded in four experiments, were subjected to spectral analysis. Waking prior to sleep varied from 12 to 36 h and sleep was initiated at different circadian phases. Power density of delta and theta frequencies in rapid-eye-movement (REM) sleep and non-REM (NREM) sleep increased monotonically as a function of prior waking. The increase of power density in the theta frequencies contrasts with the reported decrease of theta activity as detected by period-amplitude analysis. Slow wave activity (power density, 0.25-4.0 Hz) in NREM sleep during the first 3 h of sleep did not deviate significantly from the homeostatic process S of the two-process model of sleep regulation. In contrast, visually scored slow wave sleep, stages 3 and 4, deviated from this prediction at some circadian phases. It is concluded that, in accordance with the two-process model of sleep regulation, slow wave activity in NREM sleep depends on prior waking and is not significantly influenced by circadian phase.     

Walsh functions for simplifying computation of blood pressure wave power spectra

The rate of convergence of Walsh functions and sine functions to recorded blood pressure waves was determined to evaluate the applicability of Walsh functions for spectral analysis of pulsatile blood pressure. The advantages of Walsh function series for such analysis are that their calculation is much faster and can be performed on small computers. Walsh function series were computed for blood pressure waves recorded from anesthetized dogs. It was found that 13 terms of the Walsh series represented 98% of the power in the wave. An equal number of Fourier terms contained 99% of the power. Angiotensin induced hypertension produced an increase in the amplitude of the lower terms of the Walsh function series, showing that this method is sensitive to physiologic alterations in blood pressure. It is concluded that Walsh functions are a computationally faster alternative to sine functions for spectral analysis of pulsatile blood pressure. Supported by a New York University School of Medicine Honors Program Summer Research Fellowship funded by PHS General Research Grant FR 05399-10 and the John A. Hartford Foundation.     

Slow-wave sleep: do young adult men and women age differently?

The differential effects of ageing on polysomnographic and EEG spectral characteristics of sleep were explored in men and women between the ages of 20 and 40. Men and women in their twenties were found to have similar percentages of slow-wave sleep (SWS) (% Stage 3 and 4) and mean EEG slow wave activity (quantified by spectral analysis). Significant reductions in the percentage of SWS and mean slow wave activity over the night occurred in men during their thirties but not in the women. This suggests that gender difference in SWS may emerge between age 30 and 40 in young adults. Men in this sample were also found to have significant increases in Stage 2 sleep, and decreases in REM sleep time, REM activity, REM density and REM intensity. No significant effects of age were found for women in any visually scored sleep variables. Both men and women had age related reductions in spectral power in the spindle frequencies. Taken together, these findings suggest that the sleep of men and women over age 20–40 may age differently.     

Pulse wave amplitude drops during sleep are reliable surrogate markers of changes in cortical activity

Background:During sleep, sudden drops in pulse wave amplitude (PWA) measured by pulse oximetry are commonly associated with simultaneous arousals and are thought to result from autonomic vasoconstriction. In the present study, we determine whether PWA drops were associated with changes in cortical activity as determined by EEG spectral analysis.Methods:A 20% decrease in PWA was chosen as a minimum for a drop. A total of 1085 PWA drops from 10 consecutive sleep recordings were analyzed. EEG spectral analysis was performed over 5 consecutive epochs of 5 seconds: 2 before, 1 during, and 2 after the PWA drop. EEG spectral analysis was performed over delta, theta, alpha, sigma, and beta frequency bands. Within each frequency band, power density was compared across the five 5-sec epochs. Presence or absence of visually scored EEG arousals were adjudicated by an investigator blinded to the PWA signal and considered associated with PWA drop if concomitant.Results:A significant increase in EEG power density in all EEG frequency bands was found during PWA drops (P < 0.001) compared to before and after drop. Even in the absence of visually scored arousals, PWA drops were associated with a significant increase in EEG power density (P < 0.001) in most frequency bands.Conclusions:Drops in PWA are associated with a significant increase in EEG power density, suggesting that these events can be used as a surrogate for changes in cortical activity during sleep. This approach may prove of value in scoring respiratory events on limited-channel (type III) portable monitors.Citation:Delessert A; Espa F; Rossetti A; Lavigne G; Tafti M; Heinzer R. Pulse wave amplitude drops during sleep are reliable surrogate markers of changes in cortical activity. SLEEP 2010;33(12):1687-1692.     

Lateral inhibition in neural networks and the shape of EEG alpha rhythm waves

Baseline EEG traces were recorded from the right occipital area with the eyes closed in 15 subjects. Rhythmic stimulation with bright, diffuse flashes of light was applied through the closed eyelids at specific points in the alpha-wave phase (trigger photic stimulation). Ten versions of stimulation were used, with application at different phases for 1 min at each phase. Responses occurring in conditions of stimulation in different phases were compared using the mean alpha wave amplitude in each version and the wave shape in terms of the level of asymmetry of the leading and trailing fronts. When flashes were delivered at the middle of the descending front of the potential (positivization), changes in wave shape were most marked and were very different from those seen in the other nine stimulation phases. This effect was most marked in subjects with low-amplitude alpha rhythms. These results suggest that the individual level of the alpha rhythm in a given subject and the dynamics of the wave shape can be explained by the characteristics of the structure of the system of recurrent-lateral inhibition. Translated from Rossiiskii Fiziologicheskii Zhurnal imeni I. M. Sechenova, Vol. 94, No. 2, pp. 152–162, February, 2008.     

Pressure peaking in pulsatile flow through arterial tree structures

An analytical iterative scheme is presented for computing the local characteristics of pressure and flow waves as they progress along a tree structure and become modified by wave reflections. Results are obtained to illustrate the phenoenon of pressure peaking under two different sets of circumstances. In the first case, the propagation of a single harmonic wave along a simple tree is considered, where wave reflections modify the amplitude of the pressure wave as it travels. In the second case, the propagation of a composite wave along a tree with multiple branches is considered, where wave reflections modify the shape of the wave as it travels and cause it to peak. The results demonstrate unambiguously that the root cause of this phenomenon is wave reflections caused by stepwise decreases in admittance, as has been previously suggested, rather than due to nonlinear interactions, as has also been previously suggested. It is shown clearly that even when wave reflections combine linearly, they lead to considerable peaking in the pressure waveform.     

The pattern of slow wave activity in spontaneously occurring long sleep

SUMMARY  The aim of the present study was to estimate the time course of slow wave activity (SWA) in naturally occurring long sleep episodes (ad lib). Sixteen male shift workers were subjected to 24 h ambulatory polysomnography in connection with an afternoon shift. The EEG was subjected to spectral analysis (FFT) as well as to traditional sleep stage scoring. SWA (0.5-4.5 Hz band, both nonREM and REM sleep) declined exponentially and reached an asymptote by the fifth or sixth sleep cycle. However, half the subjects showed a reduced SWA in the first cycle, with a subsequent recovery in the second cycle. The SWA reduction of the first cycle was associated with a reduced REM-latency and it was suggested that uncontrolled external influences of the real life settings may have affected SWA in the first cycle. It was concluded that the decline of SWA across time may deviate from an exponential shape under real life conditions.     

指端脉搏波的非损伤测量和频谱分析

本文介绍了一种应用光学传感器和幅度调制技术进行外周动脉中脉搏波测量的原理、测量电路以及数据分析系统,利用指端脉搏波的FFT功率谱分析心搏和呼吸的频率特性,并判断心率的稳定性。     

Effect of pentobarbital on spectral characteristics and phase ratios of wave oscillations of cardiac contraction period and time of atrioventricular conduction in cats

Effects of pentobarbital on spectral characteristics and phase ratios of wave oscillations of the cardiac contraction period (RR interval) and time of atrioventricular conduction (AV interval) were studied in experiments of cats. Pentobarbital moderately reduced the mean values of both intervals and significantly reduced their standard deviations and spectral powers in all frequency bands (high-frequency, low-frequency, and very low-frequency). Pentobarbital treatment led to deceleration of breathing, the frequency range of respiratory oscillations of RR and AV intervals shifted in some cases from high to low frequencies; evaluation of spectral power in the intermittent band corresponding to respiration frequency (instead of standard fixed high-frequency band) showed that pentobarbital suppressed the respiratory oscillations in these bands. Pentobarbital induced inversion of phase ratio between respiratory oscillations of RR and AV intervals: oscillations of both intervals before pentobarbital coincided by phase, while after pentobarbital injection they were in antiphase. The mechanisms of the latter phenomenon deserve further investigation. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 141, No. 3, pp. 255–258, March, 2006