EEG signature and phenomenology of alpha/theta neurofeedback training versus mock feedback

Alpha/theta (a/t) neurofeedback training has in the past successfully been used as a complementary therapeutic relaxation technique in the treatment of alcoholism. In spite of positive clinical outcomes, doubts have been cast on the protocol's specificity when compared to alternative relaxation regimes. This study investigated the basic tenet underlying the a/t training rationale, that accurate a/t feedback representation facilitates the generation of these frequency components. Two groups of healthy volunteers were randomly assigned to either (a) real contingent a/t feedback training or (b) a noncontingent mock feedback control condition. The groups were compared on measures of theta/alpha (t/a) ratios within and across training sessions, as well as activational self-report scales after each session. The contingent a/t feedback group displayed significant within-session t/a ratio increments not evident in the mock control group, as well as higher overall t/a ratios in some but not all of the training sessions. No differences were found between the groups in terms of subjective activational phenomenology, in that both groups reported significantly lower levels of activation after training sessions. The data demonstrate that irrespective of considerations of clinical relevance, accurate a/t neurofeedback effectively facilitates production of higher within-session t/a ratios than do noncontingent feedback relaxation.     

Combined Heart Rate Variability and Pulse Oximetry Biofeedback for Chronic Obstructive Pulmonary Disease: Preliminary Findings

The purpose of this study was to examine the feasibility of an intervention that included heart rate variability (HRV) biofeedback and walking with pulse oximetry feedback to improve functioning and quality of life for patients with chronic obstructive pulmonary disease (COPD). Twenty patients with COPD participated in 5 weekly sessions of HRV biofeedback and 4 weekly sessions of walking practice with oximetry feedback, with instructions for daily home practice. Primary outcomes measures were the distance walked in 6 min (6MWD) and overall quality of life, as measured by the St. George's Respiratory Questionnaire (SGRQ). Secondary outcomes included measures of self-efficacy, self-reported disability, anxiety, depression, dyspnea before and after the 6MWD, and HRV at the frequency of respiration during spontaneous and paced breathing. After 10 weeks of training, participants showed statistically and clinically significant improvements in 6MWD and quality of life. Significant changes were also seen in self-efficacy, disability, dyspnea before and after the 6MWD, and HRV amplitude during spontaneous breathing. We conclude that our intervention is feasible for patients with COPD and that further research using a randomized controlled design is warranted.     

血管紧张素Ⅱ对家兔心率变异的影响

目的:研究血管紧张Ⅱ(AngⅡ)对家兔心率变异(HRV)影响的机制。方法:分别给家兔静脉输注生理盐水,AngⅡ,溴化六烃季胺(HEXB),HEXB+AngⅡ检测安静状态下连续5 min的心电图并进行HRV的时域和频域分析。结果:血管紧张素Ⅱ组的时域指标SDNN和RMSSD较对照组明显降低,频域指标低频(LF)升高,而高频(HF)和总功率(TP)明显降低;HEXB+AngⅡ组与HEXB组相比无明显区别。结论:交感神经阻断剂HEXB不能影响AngⅡ的作用,AngⅡ主要通过抑制中枢自主神经的传出,降低迷走神经张力来降低HRV。     

Circadian rhythm of airways caliber and its autonomic modulation

ABSTRACT

The autonomic nervous system (ANS) is one of the effector pathways for circadian variation of many physiological parameters. Autonomic tone and airways caliber have been reported to exhibit circadian variation in separate studies. A simultaneous investigation of heart rate variability (HRV) and airway caliber might ascertain how airway caliber is modulated by autonomic tone. This study was planned to identify the variations in airway caliber and autonomic function tone during a 24-hour span. A total of 56 healthy male subjects with almost similar daily routines were studied. Time domain, frequency domain and nonlinear analysis of R-R interval from 5 min electrocardiogram (ECG) was done seven times during the daytime wake span at 3-hour intervals starting at 05:00 h in the morning until 23:00 h in the night. Simultaneously peak expiratory flow rate (PEFR) was determined using a mini Wright’s peak flow meter. Rhythmometric analysis was done for PEFR and HRV parameters. Significant circadian variation in low frequency (LF) and high frequency (HF) variance was identified in this group of healthy subjects. The circadian rhythm of LF variance was characterized by a gradual increase and corresponding reciprocal change in HF variance from morning until night. The LF/HF ratio and SD2/SD1 ratio reflecting sympatho-vagal balance showed low to high values from morning to evening. The acrophase of the PEFR temporal pattern is similar to that of LF power and almost opposite in phase to that of HF power. PEFR is positively correlated with LF power. The circadian rhythm of airway caliber co-varies with cardiac autonomic tone. It appears that the temporal pattern of cardiac autonomic tone precedes in time that of airways caliber, thereby suggesting the latter operates under the modulatory effect of the 24-hour pattern in sympatho-vagal balance.     

电刺激迷走神经对蟾蜍心率和心率变异的影响

目的:观察不同频率迷走神经刺激对蟾蜍离体心脏的心率及心率变异的影响。方法:将蟾蜍心脏和右侧迷走交感干离体后,以不同频率电刺激神经,记录心电图曲线并作心率变异性(HRV)分析。结果:交感神经阻断后,电刺激迷走交感干,心率(HR)显著下降(P0.01),全部正常心动周期的标准差(SDNN)和相邻正常心动周期差值的均方根(RMSSD)显著升高(P0.01),不同频率刺激组之间没有明显差异;与对照组相比,各指标变化较大;给药组0.2Hz时高频(HF)显著升高(P0.01),低频/高频比值(LF/HF)明显降低(P0.05),0.8Hz时HF和LF/HF接近刺激前水平。结论:一定范围内增加刺激频率,迷走神经降低心率的作用增强;没有交感神经调节条件下的迷走神经对心率和心率变异的调节可能存在不同的机制。     

扩张型心肌病患者恶性室性心律失常与心率变异性关系分析

目的:了解扩张型心肌病患者恶性心律失常(MVA)与心率变异性(heart rate variability,HRV)的关系,探讨扩心病患者体内自主神经变化的临床意义。方法:选择扩心病患者48例作为研究对象,同时按照年龄配对,取48例正常者作为对照组,对其行24小时动态心电图检查,依据其是否出现恶性心律失常分为恶性室性心律失常(MVA+)组及单纯扩张型心肌病(MVA-)组,分析组间HRV的差异。结果:与对照组比较,单纯扩张型心肌病(MVA-)组HRV时域指标(SDNN、SDANN、RMSSD)均有降低(P<0.05)L与(MVA-)组相比,恶性室性心律失常(MVA+)组HRV相关指标进一步降低(P<0.05)。结论:自主神经功能异常是扩张型心肌病患者恶性心律失常的重要危险因子,可能可以用HRV预测其发生恶性心律失常危险性。     

迷走神经和交感神经系统不同活动状态对心率变异性的影响

实验在氯醛糖加氨基甲酸乙酯麻醉的新西兰兔上进行。记录血压、心率、心电图并对心电Ｒ－Ｒ间期（ＲＲＩ）作功率谱密度（ＰＳＤ）分析。以单调性电刺激和低频率的波动性电刺激分别刺激减压神经、疑核和右侧迷走神经外周端,观察到低频率的波动性刺激对增加ＰＳＤ中低频成分（ＬＦ）的作用比单调性电刺激更大（Ｐ〈０．０５）。注射新福林仅在头一个２５６个心动周期时间内引起总变异性（ＴＶ）、ＬＦ、ＰＳＤ中高频成分（ＨＦ）。Ｌ     

The Effects of Respiratory Sinus Arrhythmia Biofeedback on Heart Rate Variability and Posttraumatic Stress Disorder Symptoms: A Pilot Study

Recent studies have found a significant association between PTSD and low heart rate variability (HRV), a biomarker of autonomic dysregulation. Research indicates that respiratory sinus arrhythmia (RSA) biofeedback increases HRV while reducing related pathological symptoms. This controlled pilot study compared RSA biofeedback to progressive muscle relaxation (PMR) as adjunctive interventions for 38 persons with PTSD symptoms in a residential treatment facility for a substance use disorder. Both groups were assessed at pre-intervention and 4-week post-intervention. Group × time interactions revealed significantly greater reductions in depressive symptoms and increases in HRV indices for the RSA group. Both groups significantly reduced PTSD and insomnia symptoms and a statistical trend was observed for reduced substance craving for the RSA group. Increases in HRV were significantly associated with PTSD symptom reduction. Overall, these results provide preliminary support for the efficacy of RSA biofeedback in improving physiological and psychological health for individuals with PTSD.     

Physiological and psychological assessment of sound

 The psycho-physiological effects of several sound stimulations were investigated to evaluate the relationship between a psychological parameter, such as subjective perception, and a physiological parameter, such as the heart rate variability (HRV). Eight female students aged 21–22 years old were tested. Electrocardiogram (ECG) and the movement of the chest-wall for estimating respiratory rate were recorded during three different sound stimulations; (1) music provided by a synthesizer (condition A); (2) birds twitters (condition B); and (3) mechanical sounds (condition C). The percentage power of the low-frequency (LF; 0.05≤0.15 Hz) and high-frequency (HF; 0.15≤0.40 Hz) components in the HRV (LF%, HF%) were assessed by a frequency analysis of time-series data for 5 min obtained from R-R intervals in the ECG. Quantitative assessment of subjective perception was also described by a visual analog scale (VAS). The HF% and VAS value for comfort in C were significantly lower than in either A and/or B. The respiratory rate and VAS value for awakening in C were significantly higher than in A and/or B. There was a significant correlation between the HF% and the value of the VAS, and between the respiratory rate and the value of the VAS. These results indicate that mechanical sounds similar to C inhibit the para-sympathetic nervous system and promote a feeling that is unpleasant but alert, also suggesting that the HRV reflects subjective perception. Received: 28 June 1996 / Revised: 6 January 1997 / Accepted: 10 January 1997     

Welfare implication of measuring heart rate and heart rate variability in dairy cattle: literature review and conclusions for future research

Heart rate (HR) measurements have been used to determine stress in livestock species since the beginning of the 1970s. However, according to the latest studies in veterinary and behaviour–physiological sciences, heart rate variability (HRV) proved to be more precise for studying the activity of the autonomic nervous system. In dairy cattle, HR and HRV indices have been used to detect stress caused by routine management practices, pain or milking. This review provides the significance of HR and HRV measurements in dairy cattle by summarising current knowledge and research results in this area. First, the biological background and the interrelation of the autonomic regulation of cardiovascular function, stress, HR and HRV are discussed. Equipment and methodological approaches developed to measure interbeat intervals and estimate HRV in dairy cattle are described. The methods of HRV analysis in time, frequency and non-linear domains are also explained in detail emphasising their physiological background. Finally, the most important scientific results and potential possibilities for future research are presented.     

Applied Psychophysiology: Beyond the Boundaries of Biofeedback (Mending a Wall, a Brief History of Our Field, and Applications to Control of the Muscles and Cardiorespiratory Systems)

The field of applied psychophysiology overlaps a number of others, from behavioral and psychosomatic medicine to Eastern disciplines and complementary medicine. Although the proliferation of societies and professional identities across these fields emphasizes this diversity, it also may hinder growth. The history of our field is one of innovation, often at odds with conventional wisdom and practice. It is important that this innovativeness not be sacrificed in a justified quest for professional respectability. This paper reviews the earliest research in biofeedback and applied psychophysiology, and modern applications and interpretations in the areas of muscular and autonomic control, including progressive relaxation and heart rate variability biofeedback, and draws parallels to disciplines of Yoga, QiGong, and Zen practices and their psychophysiological effects.     

Neurofeedback treatment for attention-deficit/hyperactivity disorder in children: a comparison with methylphenidate

Clinical trials have suggested that neurofeedback may be efficient in treating attention-deficit/hyperactivity disorder (ADHD). We compared the effects of a 3-month electroencephalographic feedback program providing reinforcement contingent on the production of cortical sensorimotor rhythm (12–15 Hz) and beta1 activity (15–18 Hz) with stimulant medication. Participants were N = 34 children aged 8–12 years, 22 of which were assigned to the neurofeedback group and 12 to the methylphenidate group according to their parents' preference. Both neurofeedback and methylphenidate were associated with improvements on all subscales of the Test of Variables of Attention, and on the speed and accuracy measures of the d2 Attention Endurance Test. Furthermore, behaviors related to the disorder were rated as significantly reduced in both groups by both teachers and parents on the IOWA-Conners Behavior Rating Scale. These findings suggest that neurofeedback was efficient in improving some of the behavioral concomitants of ADHD in children whose parents favored a nonpharmacological treatment.     

正常人和无睡眠呼吸异常慢病患者睡眠期间的呼吸源性心率变异初步报告*

目的: 整体整合生理学医学新理论-呼吸循环代谢等系统一体化调控提出了呼吸为循环指标变异性起源的假说,我们对人睡眠期间的呼吸和心率变异分别分析,探索心率变异的起源。方法: 本研究回顾性分析了2014年以来行心肺运动试验（CPET）、多导睡眠图（PSG）鼻气流和心电图监测的8例无疾病诊断的正常人和10例无睡眠呼吸异常的慢性疾病患者,分析夜晚睡眠期间鼻气流的呼吸周期与心电图R-R间期心率变异周期的关系。一个完整的呼吸周期包括吸气过程和紧接着的呼气过程,分析计算呼吸周期数、平均呼吸周期时间等指标。心率由心电图的R-R间期计算获得,连续一次心率由最低点上升至最高点,再由最高点下降至最低点,为一个心率变异周期,计算心率变异周期数、平均心率变异时间、心率变异平均幅度等指标。比较同一人呼吸和心率变异指标之间的相互关系,以及两组人群之间的异同。结果: 正常人峰值摄氧量、无氧阈等CPET核心指标均显著优于无睡眠呼吸异常的慢性疾病患者（P<0.05）。正常人AHI（（1.7±1.3）次/小时）和无睡眠呼吸异常慢性疾病患者AHI（（2.9±1.2）次/小时）无差异（P>0.05）。正常人呼吸周期数与心率变异周期数（（6581.63±1411.90）次、（6638.38±1459.46）次）、平均呼吸周期时间与平均心率变异周期时间（（4.19±0.57）s、（4.16±0.62）s）均高度一致,无差异（P>0.05）。无睡眠呼吸异常的慢性疾病患者上述指标比较（（7354.50±1443.50）次与（7291.20±1399.31）次、（4.20±0.69）s与（4.23±0.68）s）也是高度一致,无统计学差异（P>0.05）。正常人呼吸周期数/心率变异周期数（0.993±0.027）与无睡眠呼吸异常的慢性疾病患者呼吸周期数/心率变异周期数（1.008±0.024）比值均接近1。正常人心率变化平均幅度（（5.74±3.21） bpm）略高于无睡眠呼吸异常的慢性疾病患者（（2.88±1.44） bpm,P<0.05）。结论: 正常人和无睡眠呼吸异常的慢性疾病患者无论功能状态如何,心率变异与呼吸存在极其相似的一致性,其心率变异的始发因素均为呼吸所致。     

A Pilot Study on the Effects of Heart Rate Variability Biofeedback in Patients with Depression and in Healthy Subjects

Decreased vagal activity and increased sympathetic arousal have been proposed as major contributors to the increased risk of cardiovascular mortality in patients with depression. It was aim of the present study to assess the feasibility of using heart rate variability (HRV) biofeedback to treat moderate to severe depression. This was an open-label study in which 14 patients with different degrees of depression (13 f, 1 m) aged 30 years (18–47; median; range) and 12 healthy volunteers attended 6 sessions of HRV biofeedback over two weeks. Another 12 healthy subjects were observed under an active control condition. At follow up BDI was found significantly decreased (BDI 6; 2–20; median 25%–75% quartile) as compared to baseline conditions (BDI 22;15–29) in patients with depression. In addition, depressed patients had reduced anxiety, decreased heart rate and increased HRV after conduction of biofeedback (p < 0.05). By contrast, no changes were noted in healthy subjects receiving biofeedback nor in normal controls. In conclusion, HRV biofeedback appears to be a useful adjunct for the treatment of depression, associated with increases in HRV.     

大鼠缺血性脑损伤引起学习记忆障碍及心率变异性改变

本研究通过建立高脂缺血性脑损伤大鼠模型,进行水迷宫实验和心率变异性（heart rate variability,HRV）的功率谱分析,探讨脑损伤前后大鼠学习记忆的变化及缺血对自主神经的影响。23只成年雄性Wistar大鼠随机分为对照组（n=10）、高脂组（n=6）和高脂缺血组（n=7）。高脂组和高脂缺血组大鼠均饲以高脂饲料制成高血脂大鼠模型。各组大鼠进行水迷宫实验后,高脂缺血组用双侧颈总动脉结扎（2-VO）法制作缺血再灌注模型,同时记录心电图。7d后各组大鼠再次进行水迷宫实验和记录心电图,对HRV序列进行基于快速傅立叶转换（fast Fourier transformation,FFT）的功率谱分析。结果：（1）第一次水迷宫测试,3组大鼠空间探索实验和定位航行实验结果无统计学差异;第二次水迷宫实验,高脂缺血组与其它两组相比,空间探索实验中平台所在象限的记忆频度明显下降（P〈0．01）,定位航行实验中平台所在象限的记忆频度显著下降（P〈0．01）,10圆环记忆得分显著下降（P〈0．001）,但高脂组与对照组相比无明显差异。（2）高脂缺血组缺血后心率持续下降;缺血时HRV中频段功率（0．2加．6Hz）呈现明显下降的趋势,高频段功率（0．6-2．5Hz）缓慢下降,中频／高频功率比值明显下降（P〈0．05）。（3）缺血7d后高脂缺血组与高脂组相比,心率明显加快,HRV的中频段功率无显著变化,高频段功率明显下降,中频／高频功率比值显著增高（P〈0．05）。结果表明,缺血过程中高脂缺血组大鼠的自主神经活动降低,交感神经活动相对于迷走神经活动减弱。缺血7d后,由于海马区神经元对缺血敏感易受损,造成高脂缺血组大鼠学习记忆障碍,同时引发迷走神经活动下降,大鼠交感．迷走神经系统平衡失调。     

Hypersensitivity to RF fields emitted from CDMA cellular phones: A provocation study

With the number of cellular phone users rapidly increasing, there is a considerable amount of public concern regarding the effects that electromagnetic fields (EMFs) from cellular phones have on health. People with self‐attributed electromagnetic hypersensitivity (EHS) complain of subjective symptoms such as headaches, insomnia, and memory loss, and attribute these symptoms to radio frequency (RF) radiation from cellular phones and/or base stations. However, EHS is difficult to diagnose because it relies on a person's subjective judgment. Various provocation studies have been conducted on EHS caused by Global System for Mobile Communications (GSM) phones in which heart rate and blood pressure or subjective symptoms were investigated. However, there have been few sham‐controlled provocation studies on EHS with Code Division Multiple Access (CDMA) phones where physiological parameters, subjective symptoms, and perception of RF radiation for EHS and non‐EHS groups were simultaneously investigated. In this study, two volunteer groups of 18 self‐reported EHS and 19 non‐EHS persons were tested for both sham and real RF exposure from CDMA cellular phones with a 300 mW maximum exposure that lasted half an hour. We investigated not only the physiological parameters such as heart rate, respiration rate, and heart rate variability (HRV), but also various subjective symptoms and the perception of EMF. In conclusion, RF exposure did not have any effects on physiological parameters or subjective symptoms in either group. As for EMF perception, there was no evidence that the EHS group better perceived EMF than the non‐EHS group. Bioelectromagnetics 30:641–650, 2009. © 2009 Wiley‐Liss, Inc.     

Radio frequency electromagnetic field exposure in humans: Estimation of SAR distribution in the brain,effects on sleep and heart rate

In two previous studies we demonstrated that radiofrequency electromagnetic fields (RF EMF) similar to those emitted by digital radiotelephone handsets affect brain physiology of healthy young subjects exposed to RF EMF (900 MHz; spatial peak specific absorption rate [SAR] 1 W/kg) either during sleep or during the waking period preceding sleep. In the first experiment, subjects were exposed intermittently during an 8 h nighttime sleep episode and in the second experiment, unilaterally for 30 min prior to a 3 h daytime sleep episode. Here we report an extended analysis of the two studies as well as the detailed dosimetry of the brain areas, including the assessment of the exposure variability and uncertainties. The latter enabled a more in depth analysis and discussion of the findings. Compared to the control condition with sham exposure, spectral power of the non-rapid eye movement sleep electroencephalogram (EEG) was initially increased in the 9-14 Hz range in both experiments. No topographical differences with respect to the effect of RF EMF exposure were observed in the two experiments. Even unilateral exposure during waking induced a similar effect in both hemispheres. Exposure during sleep reduced waking after sleep onset and affected heart rate variability. Exposure prior to sleep reduced heart rate during waking and stage 1 sleep. The lack of asymmetries in the effects on sleep EEG, independent of bi- or unilateral exposure of the cortex, may indicate involvement of subcortical bilateral projections to the cortex in the generation of brain function changes, especially since the exposure of the thalamus was similar in both experiments (approx. 0.1 W/kg).     

Heart Rate Orcadian Rhythm as a Biological Marker of Desynchronization in Major Depression: A Methodological and Preliminary Report

Heart rate (HR) was continuously monitored during successive 24-hr periods in 19 healthy subjects and 26 major depressed patients (DSM III-R). Recordings were performed after a 2-week wash-out period and the morningness or eveningness typology of each subject was determined. The chronobiological parameters and rhythm percentage (RP) were calculated by the single cosinor method from the smoothed HR curves of each subject. In normal subjects, HR follows a circadian rhythm (RP > 65%) with the lowest values at night. Morning type subjects have an earlier peak time (13:30) than evening type subjects (17:30). Major depressive patients were split into two groups; in the first one HR circadian rhythm was still present (RP > 63%) with a decrease in amplitude (24%) while in the second group, no circadian rhythm of HR could be detected (RP < 25%, decrease in amplitude > 70%). In the group of patients with a persisting HK circadian rhythm, no veritable phase advance was observed. Our results suggest that circadian HR rhythm, which can be easily studied with non-invasive methods, might represent a chronobiological marker of some depressions. Given the lag that exists between the rhythms of morning type and evening type subjects, our study also stresses the importance of taking into account this behavioural trait in chronobiological studies.     

呼中林区森林景观的历史变域模拟及评价

在大兴安岭地区呼中区,将物种的年龄和分布信息进行随机化处理后,应用空间直观景观模型LANDIS对森林景观进行长时间(2500a)模拟,取物种演替稳定时间段作为模拟历史变域的数据来源.分别在景观水平和年龄类型水平上利用景观指数空间分析、主成分分析和核密度估计方法分析景观格局历史变域的模拟结果,并在二维空间坐标内,将研究区1990年、2000年森林景观特征与之比较.结果表明,各树种面积比例在模拟900a后都达到稳定状态,可作为无干扰条件下森林景观特征的历史变域;由于长期采伐,研究区1990年景观的斑块面积和破碎化程度都偏离了该历史变域,其中,过熟林偏离最明显,其斑块面积远小于历史变域,破碎化程度非常严重;虽然1990年后的采伐管理方案比之前的更为合理,但2000年的森林景观仍旧继续偏离历史变域.