Correction: Musical Neurofeedback Advancements, Feedback Modalities, and Applications: A Systematic Review
The Effect of Heart Rate Variability Biofeedback on Recovery After Aerobic Exercise
Recovery is a critical factor in athletic performance, and accelerating this process is essential to enable athletes to perform more effectively in both training load and competitive performance. After exercise, immediate recovery is potentially helpful for investigating autonomic activity levels, as they are definable with heart rate variability (HRV). The purpose of this study was to examine the effect of ten sessions of HRV-Biofeedback (HRV-BF) training on recovery process parameters after the aerobic performance. In this study, twenty-four soccer players aged 18-24 volunteered to participate. The athletes who met the research criteria were divided into an experimental group (n = 12) and a control group (n = 12). Each participant's height, weight, BMI, body fat percentage, and aerobic capacity were measured before and after the 10-session intervention. The experimental group participated in a 10-session HRV-BF training and soccer training program, while the control group only participated in a 10-session soccer training program. Aerobic capacity tests were then applied again to experimental and control group participants. The effect of biofeedback on the three HRV parameters during the 5-minute acute recovery period after the test was investigated. The results showed that regularly applied HRV-BF training can significantly shorten the HRV recovery parameter after exercise. Specifically, the athletes who performed HRV-BF training demonstrated faster cardiovascular recovery after aerobic exercise. This suggests that implementing HRV-BF training for athletes can significantly accelerate their recovery processes during and after competitions. Given recent technological advancements, it is promising to consider adding HRV-BF training to stress management interventions, particularly in relation to physiological stress indicators.
Physiological Effects of Psychological Interventions Among Persons with Financial Stress: A Systematic Review, Meta-analysis, and Introduction to Psychophysiological Economics
It is known that economic problems can cause psychological stress, and that psychological stress causes physiological changes often linked to disease. Here we report a systematic review and meta-analysis of studies on physiological effects of psychological treatment for individuals with economic problems. Of 5071 papers in our initial PsycInfo search, we identified 16 papers on physiological effects for psychological treatment of the economically stressed. We found 11 controlled studies, among which we found a small to moderate significant effect size, Hedges' g = 0.319, p < 0.001. The largest effect sizes were found for heart rate variability and measures of inflammation, and the smallest for measures involving cortisol. The studies were all on chronically poor populations, thus restricting generalization to other financially stressed populations such as students, athletes in training, and those stressed by relative deprivation compared with neighbors or other reference groups. None of the studies examined effects of these psychophysiological changes on disease susceptibility, and none included elements of financial planning. The nascent field of financial psychophysiology calls for more research in these areas. Even so, results suggest that financially stressed people can benefit physiologically from psychological stress management methods.
Alpha Neurofeedback Training in Elite Soccer Players Trained in Groups
Neurofeedback training is applied in the world of sports as a means to improve athletes' performance. Training sessions are usually organized on an individual basis, one at a time. Here we investigated if the training could also be organized in groups. Forty-one national-level football (soccer) players (26 females, 15 males) carried out training sessions simultaneously in groups of up to 13, using a wearable device with Bluetooth connection, during their regular training hours at the club. It was possible to obtain good EEG measurements using this setup, albeit with a somewhat higher data loss than usual in standard laboratory sessions. The brain's alpha activity was trained using music-based neurofeedback in a crossover design. A training session consisted of alternating periods of neurofeedback and execution of cognitive tasks. EEG alpha (8-12 Hz) activity was higher in the neurofeedback periods compared to the cognitive task periods, and the reverse was true for beta (13-30 Hz) activity. The training program resulted in an increase of 34% in alpha activity associated with the training, and improved the athletes' performance on task switching and mental rotation tasks. In addition, self-reported sleep duration, as well as scores on the Being in Shape questionnaire (Feeling of Control and Flow) also improved. This study shows that neurofeedback training is feasible in groups of athletes, which can stimulate its application in team sports.
Validity of Ultra-Short-Term Heart Rate Variability Derived from Femoral Arterial Pulse Waveform in a British Military Cohort
Various non-electrocardiogram (ECG) based methods are considered reliable sources of heart rate variability (HRV) measurement. However, the ultra-short recording of a femoral arterial waveform has never been validated against the gold-standard ECG-based 300s HRV and was the aim of this study.A validity study was conducted using a sample from the first follow-up of the longitudinal ADVANCE study UK. The participants were adult servicemen (n = 100); similar in age, rank, and deployment period (Afghanistan 2003-2014). The femoral arterial waveforms (14s) from the pulse wave velocity (PWV) assessment, and ECG (300s) were recorded at rest in the supine position using the Vicorder™ and Bittium Faros™ devices, respectively, in the same session. HRV analysis was performed using Kubios Premium. Resting heart rate (HR) and root mean square of successive differences (RMSSD) were reported. The Bland-Altman %plots were constructed to explore the PWV-ECG agreement in HRV measurement. A further exploratory analysis was conducted across methods and durations.The participants' mean age was 38.0 ± 5.3 years. Both PWV-derived HR (r = 0.85) and RMSSD (r=0.84) showed strong correlations with their 300s-ECG counterparts (p < 0.001). Mean HR was significantly higher with ECG than PWV (mean bias: -12.71 ± 7.73%, 95%CI: -14.25%, -11.18%). In contrast, the difference in RMSSD between the two methods was non-significant [mean bias: -2.90 ± 37.82% (95%CI: -10.40%, 4.60%)] indicating good agreement. An exploratory analysis of 14s ECG-vs-300s ECG measurement revealed strong agreement in both RMSSD and HR.The 14s PWV-derived RMSSD strongly agrees with the gold-standard (300s-ECG-based) RMSSD at rest. Conversely, HR appears method sensitive.
A Systematic Review of the Relationship Between Traumatic Brain Injury and Disruptions in Heart Rate Variability
Autonomic nervous system dysfunction is increasingly recognized as a common sequela of traumatic brain injury (TBI). Heart rate variability (HRV) is a specific measure of autonomic nervous system functioning that can be used to measure beat-to-beat changes in heart rate following TBI. The objective of this systematic review was to determine the state of the literature on HRV dysfunction following TBI, assess the level of support for HRV dysfunction following TBI, and determine if HRV dysfunction predicts mortality and the severity and subsequent recovery of TBI symptoms. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Two raters coded each article and provided quality ratings with discrepancies resolved by consensus. Eighty-nine papers met the inclusion criteria. Findings indicated that TBI of any severity is associated with decreased (i.e., worse) HRV; the severity of TBI appears to moderate the relationship between HRV and recovery; decreased HRV following TBI predicts mortality beyond age; HRV disturbances may persist beyond return-to-play and symptom resolution following mild TBI. Overall, current literature suggests HRV is decreased following TBI and may be a good indicator of physiological change and predictor of important outcomes including mortality and symptom improvement following TBI.
Assessing the Feasibility of EMG Biofeedback to Reduce the Upper Trapezius Muscle Excitation during a Seated Row Exercise, a Non-randomized Comparative Study
The upper trapezius muscle is often excessively excited during resistance training exercises, increasing the shoulder's liability to musculoskeletal disorders of individuals participating in overhead sports or throwing activities. Different approaches have been proposed for reducing the potentially harmful loading of the upper trapezius. None, however, has been devised to deal directly with the main culprit: the muscle excitation. This non-randomized comparative study explores the feasibility of biofeedback based on surface electromyograms (EMGs) in suppressing undue excitation of the upper trapezius during a seated row exercise. Eight male volunteers were instructed to perform the wide-grip seated row exercise without and with the EMG biofeedback of the upper trapezius. Surface EMGs from the three portions of the trapezius and the serratus anterior were sampled with pairs of surface electrodes. A triaxial accelerometer was positioned on the weight stack for the identification of the exercise phase and repetition. This study showed that during the "with biofeedback" condition, the participants were able to activate the upper trapezius and serratus anterior to a lower degree (~ 10%) compared to the "without biofeedback" condition. Future studies should explore if this can lead to greater gains in muscle performance and/or reduce the risk of shoulder injury.
Heart Rate Variability Biofeedback Intervention Programme to Improve Attention in Primary Schools
The importance of attentional capacity for academic performance is highlighted by the increasing demands placed on students during primary school. Between the ages of 7 and 12, there is an evolutionary improvement in attentional capacity and the school environment is considered an appropriate setting in which to develop programmes to improve attention. Heart rate variability is an appropriate indicator of attentional capacity. For all these reasons, a heart rate variability biofeedback intervention focused on breathing was developed and implemented to improve attention. The intervention consisted of two phases. In the first phase, the school teachers were trained to develop the intervention; in the second, students received five individual sessions from their teachers. In each individual session, they learned to breathe to increase their heart rate variability. A total of 272 girls and 314 boys (N = 586) aged 7-12 years participated in the programme. To study the impact of the intervention on three primary school age groups, the attention of Control and Experimental groups was assessed before and after the implementation of the programme. According to the data obtained, despite developmental improvements, the students who participated in the programme showed an increase in heart rate variability and an improvement in attentional capacity, with a greater impact on the first cycle of primary school. The usefulness of heart rate variability biofeedback interventions in improving attention in primary school is discussed and arguments for their use in children are presented.
Childhood Family Stress and Women's Health: Parasympathetic Activity as a Risk and Resiliency Factor
Childhood family stress (CFS) exacerbates risk for physical health problems across the lifespan. Health risks associated with CFS are particularly relevant for women who tend to endorse more CFS than men. Importantly, some evidence suggests that individuals may vary in their susceptibility to CFS. Parasympathetic activity, which helps to regulate automatic bodily activity (e.g., breathing, digestion), has been proposed to represent a marker of plasticity to environmental exposure. However, no research to date has tested whether parasympathetic activity may modulate the impact of early adversity on health. We examined whether parasympathetic activity would moderate the link between CFS and health complaints in a sample of 68 undergraduate women (Mean age = 19.44). Participants self-reported CFS and health complaints. Parasympathetic activity was indexed using high-frequency heart rate variability (HF-HRV) and was evaluated by measuring changes in HF-HRV in response to and following a laboratory-based stress induction. Multiple regression analyses indicated that CFS was significantly associated with more health complaints. Further, HF-HRV in response to stress and during recovery relative to baseline significantly moderated relationship between CFS and health complaints. Specifically, more CFS was significantly associated with more health complaints among women who showed mean or greater decreases in HF-HRV in response to stress. Additionally, lower levels of CFS were associated with fewer health complaints among women who showed mean or greater HF-HRV during recovery relative to baseline. Findings highlight the importance of parasympathetic activity in modulating stress-health links.
Clinical Observation of Acupuncture Combined with Biofeedback Electrical Stimulation in the Treatment of Female Stress Urinary Incontinence
To investigate the clinical efficacy of acupuncture combined with biofeedback electrical stimulation on female stress urinary incontinence. Ninety patients diagnosed in a hospital between January 2020 and January 2021 were randomly divided into three groups (A, B and C). Group A was treated with biofeedback electrical stimulation, 3 times a week for 30 min for 15 times. Group B used acupuncture treatment, including Guanyuan, Qihai, Zhongji, Zusanli, Sanyinjiao and Yinlingquan, once a day, Monday-Friday, 30 min each, for a total of 10 times. Group C was treated with acupuncture combined with biofeedback electrical stimulation. All three groups were combined with pelvic floor muscle training. Following treatment, the changes in class I and II muscle fibre strength, ICI-Q-SF score and urine leakage in the 1-hour pad test were compared. Prior to treatment, there was no significant difference in the general data of the three patient groups, as well as class I and II muscle fibre strength, ICI-Q-SF score and 1-hour urinary pad test (P > 0.05). Following treatment, class I and II muscle fibre strength in groups A and C improved compared with before, with statistical significance (P < 0.05); there was no significant difference in group B (P > 0.05). In the three groups, ICI-Q-SF scores and 1-hour urinary pad test results were lower compared with before (P < 0.05), with those in group C better than those in groups A and B (P < 0.05). The treatment efficiency of the three patient groups was 86.7%, 83.3% and 96.7%, respectively. Combined acupuncture and biofeedback electrical stimulation can improve pelvic floor muscle strength, urine leakage and quality of life, and can be superior to biofeedback and acupuncture treatment alone.
Vagally Mediated Heart Rate Variability and Mood States in Patients with Chronic Pain Receiving Prolonged Expiration Regulated Breathing: A Randomized Controlled Trial
Reduced vagally mediated heart rate variability (VmHRV) has been reported in patients with chronic pain. In healthy persons, breathing with longer expiration relative to inspiration increases VmHRV at 12 breaths per minute. The present study aimed to determine the immediate effect of breathing with longer expiration relative to inspiration on VmHRV and mood states in patients with chronic pain. Fifty patients with chronic pain aged between 20 and 67 years were prospectively randomized as two groups with an allocation ratio of 1:1. The interventional group practiced breathing with metronome based visual cues, maintaining an inspiration to expiration ratio of 28:72 (i/e ratio, 0.38) at a breath rate of 12 breaths per minute. The average i/e ratio they attained based on strain gauge respiration recording was 0.685 (SD 0.48). The control group, which looked at the metronome without conscious breath modification had an average i/e ratio of 0.745 (SD 0.69). The VmHRV, respiration and self-reported mood states (using the Brief Mood Introspection Scale (BMIS)) were assessed. There was a significant increase in HF-HRV and RMSSD during low i/e breathing (repeated measures ANCOVA, Bonferroni adjusted post-hoc test, p < 0.05; in all cases). Self-reported mood states changed as follows: (i) following low i/e breathing positive-mood states increased while the aroused mood state decreased whereas (ii) following the control intervention the aroused mood state increased (repeated measure ANOVA, p < 0.05; in all cases). Hence breathing with prolonged expiration is possibly useful to increase VmHRV and improve self- reported mood states in patients with chronic pain.
Heart Rate Variability Biofeedback Training Reduces Early Maternal Stress, Anxiety, and Depression in Women Undergoing Cesarean Delivery: A Randomized Controlled Trial
Women who undergo cesarean delivery have reported experiencing mood distress related to the surgery and postoperative pain. Heart rate variability biofeedback (HRVB) training is known to have positive effects on mental health, but its effects on women undergoing cesarean delivery have not yet been determined. This study evaluated the effects of an HRVB training intervention on stress, anxiety, and depression in women undergoing cesarean delivery. We hypothesized that 10 sessions of HRVB training could cumulatively improve emotion regulation in participants. This study was designed as a double-blinded randomized controlled trial involving a total of 86 enrolled women who were then divided into two groups: intervention and control. During their hospitalization, the intervention group underwent HRVB training daily, while both groups received standard perinatal care. Heart rate variability (HRV) was assessed using root mean square of successive differences (RMSSD), standard deviation of normal-to-normal intervals (SDNN), high-frequency power (HF) and low-frequency power (LF). HRV parameters, stress, anxiety, and depression were evaluated at baseline and on the fifth day after childbirth. Intention-to-treat (ITT) analyses examined change over time between groups. Although no significant effects were found for the RMSSD and HF, a significant increase was observed in SDNN (F = 13.43, p = < 0.001, ƞ = 0.14), and LF at post-assessment (F = 4.26, p = .04, ƞ = 0.05) compared to the control group. Except for the depression variable, stress (F = 6.11, p = .02, ƞ = 0.07) and anxiety (F = 8.78, p = .004, ƞ = 0.10) significantly decreased compared to the control group on the fifth postpartum day. Furthermore, post-hoc analysis showed that HRVB was more effective in decreasing mild to severe depressive symptoms (F = 7.60, p = .001, ƞ = 0.27). The intervention program successfully decreased self-perceived stress and anxiety in the postpartum period and relieved symptoms in more severely depressed participants. Our findings suggest that this program is suitable and beneficial for application in women during the early postpartum period following cesarean delivery.
Correction: Applications of Alpha Neurofeedback Processes for Enhanced Mental Manipulation of Unfamiliar Molecular and Spatial Structures
Experimental Study on Emergency Psychophysiological and Behavioral Reactions to Coal Mining Accidents
Effective emergency responses are crucial for preventing coal mine accidents and mitigating injuries. This paper aims to investigate the characteristics of emergency psychophysiological reactions to coal mine accidents and to explore the potential of key indicators for identifying emergency behavioral patterns. Initially, virtual reality technology facilitated a simulation experiment for emergency escape during coal mine accidents. Subsequently, the characteristics of emergency reactions were analyzed through correlation analysis, hypothesis testing, and analysis of variance. The significant changes in physiological indicators were then taken as input features and fed into the three classifiers of machine learning algorithms. These classifications ultimately led to the identification of behavioral patterns, including agility, defensiveness, panic, and rigidity, that individuals may exhibit during a coal mine accident emergency. The study results revealed an intricate relationship between the mental activities induced by accident stimuli and the resulting physiological changes and behavioral performances. During the virtual reality simulation of a coal mine accident, subjects were observed to experience significant physiological changes in electrodermal activity, heart rate variability, electromyogram, respiration, and skin temperature. The random forest classification model, based on SCR + RANGE + IBI + SDNN + LF/HF, outperformed all other models, achieving accuracies of up to 92%. These findings hold promising implications for early warning systems targeting abnormal psychophysiological and behavioral reactions to emergency accidents, potentially serving as a life-saving measure in perilous situations and fostering the sustainable growth of the coal mining industry.
Effects of Heart Rate Variability Biofeedback Training on Anxiety Reduction and Brain Activity: a Randomized Active-Controlled Study Using EEG
Heart rate variability biofeedback (HRVBF) is a promising anxiety-reducing intervention that increases vagally-mediated heart rate variability (vmHRV) through slow-paced breathing and feedback of heart rhythm. Several studies have reported the anxiety-reducing effects of HRVBF; however, some studies have reported such training as ineffective. Furthermore, the effects of training and underlying brain activity changes remain unclear. This study examined the anxiety-reducing effects of HRVBF training and related brain activity changes by randomly assigning participants, employing an active control group, and measuring anxiety-related attentional bias using the emotional Stroop task and electroencephalography (EEG). Fifty-five healthy students with anxiety were randomly assigned to the HRVBF or control groups, and 21 in the HRVBF group and 19 in the control group were included in the analysis. Both groups performed 10 training sessions of 20 min each within 3 weeks. They were assessed using resting vmHRV, event-related potential (ERP), time-frequency EEG, attentional bias, and the State-Trait Anxiety Inventory-JYZ (STAI-JYZ) before and after training. The results demonstrated increased resting vmHRV in the HRVBF group compared to the control group after training. However, no differences were observed in ERP, time-frequency EEG, attentional bias, and STAI-JYZ. Participants with higher pre-training resting vmHRV achieved higher heart rhythm coherence in HRVBF training and had reduced attentional bias. This study suggests that individuals with higher resting vmHRV are more likely to be proficient in HRVBF training and benefit from its anxiety-reducing effects. The findings contribute to participant selection to benefit from HRVBF training and modification of the training protocols for non-responders.Clinical trial registrationOrganization: University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR), JapanRegistration number: UMIN000047096Registration date: March 6, 2022.
Brief Report: Baseline HRV Time Domain Parameters Predict Trauma and Depression Symptom Change in Veterans with PTSD Undergoing Biofeedback
Heart rate variability (HRV) is an index of cardiac autonomic function and an objective biomarker for stress and health. Improving HRV through biofeedback has proven effective in reducing symptoms of posttraumatic stress disorder (PTSD) and depression in veteran populations. Brief protocols involving fewer sessions can better maximize limited clinic resources; however, there is a dearth of knowledge on the number of clinical sessions needed to significantly reduce trauma and depression symptoms. We conducted a series of linear regression models using baseline, post-intervention, and follow-up data from intervention group participants (N = 18) who engaged in a pilot waitlist-controlled study testing the efficacy of a 3-session mobile app-adapted HRV biofeedback intervention for veterans with PTSD. Based on Nunan et al. (Pacing and Clinical Electrophysiology 33:1407-1417, 2010) short-term norms, we found that pre-intervention RMSSD in the normal range significantly predicted PTSD and depression symptom improvement. Findings suggest the utility of baseline RMSSD as a useful metric for predicting HRV biofeedback treatment outcomes for veterans with PTSD and comorbid depression. Those with below-normal baseline RMSSD may likely need additional sessions or an alternative treatment to show clinically meaningful symptom improvement.
Heart Rate Variability, Hypnosis, and Psychotherapy
Hypnotherapy is increasingly recognized as an effective treatment option for a wide range of psychological conditions and the psychological elements of physiologic health concerns. Despite its growing use, the mechanisms underlying hypnotherapy's therapeutic benefits remain unknown. Heart rate variability (HRV), a non-invasive biomarker of autonomic nervous system (ANS) activity and other processes relevant to the psychophysiological stress response, has been used to study the physiological effects of hypnosis. HRV is associated with adaptability to stress and overall mental and physical health. We review how HRV changes during hypnosis treatment and propose mechanisms by which hypnotherapy influences the stress response and psychological flexibility and improves wellbeing. Additionally, we highlight the use of HRV biofeedback as an adjunct to hypnotherapy and psychotherapy and illustrate its potential to enhance therapeutic outcomes. To showcase practical applications, we present a case study of hypnotherapy's impact on HRV in the treatment of hot flashes in post-menopausal women. We conclude by calling for further empirical research, particularly randomized controlled trials, to solidify the integration of HRV metrics in hypnotherapy practice. Understanding the interaction between hypnotherapy and HRV will support more targeted and effective interventions, benefiting both clinicians and patients.
Effect of Biofeedback Combined with Psychotherapy on Functional Constipation Complicated with Anxiety and Depression
Biofeedback combined with psychotherapy has been recognized as a potential treatment for patients with functional constipation, anxiety and depression disorder. To validate the therapeutic effect of the biofeedback therapy, 120 patients with a clear diagnosis of functional constipation combined with anxiety and depression disorder were recruited, and then randomly divided into the control group (patients received gastrointestinal medication and anti-anxiety and depression medication) and the treatment group (patients received combined biofeedback and psychotherapy on the basis of the control group's treatment program). The treatment group was treated with biofeedback exercise twice a day for 7 days, supplemented with psychotherapy for a period of 2 months (half-month intervals for one time). Intestinal medications in the treatment group were stopped after one month of treatment. While for the control group, patients were maintained with gastrointestinal motivational drugs, probiotics, anti-anxiety and depression medications. Both groups reduced the dosage of anxiolytics and depressants after 3 months. The control and the treatment group were both effective and the latter had a more significant effect compared to the former. Moreover, the anxiety/depression symptom for patients in the treatment group was significantly milder than those in the control group. Notably, compared with pre-treatment symptoms, the treatment group showed a significant reduction in Pittsburgh sleep quality index (PSQI) scores in the sixth month (F = 0.008, P = 0.008). In summary, biofeedback combined with psychotherapy may improve relieve constipation patients' clinical symptoms, anxiety/depression state and sleep quality. The treatment is durable, safe, and easy to implement, so it is suitable for widely used.
Effects of Frontal-Midline Theta Neurofeedback with Different Training Directions on Goal-Directed Attentional Control
As a significant component of executive function, goal-directed attentional control is crucial for cognitive processing and is closely linked to frontal-midline theta (FMT) rhythms. However, how up-regulation and down-regulation of FMT through neurofeedback training (NFT) impact goal-directed attention control remains unclear, especially for both short-term and long-lasting effects. Therefore, this study employed a single-blind sham-controlled between-subject design to answer this question. Forty-seven healthy adults were randomly assigned to the up-regulation, down-regulation, or sham control groups. Each group underwent one NFT session per day at the Fz electrode site for four consecutive days. All participants completed a visual search task before, immediately after the first, after the final, and one week following the last NFT session. The down-regulation group significantly reduced FMT activity during NFT and in the resting state (p < = 0.038), while the up-regulation group only showed an upward trend during the training phase (r = 0.721, p = 0.002). The behavioral performance showed no significant improvement in any group (p > 0.05). Importantly, the FMT learning efficacy in the up-regulation group revealed a significantly negative correlation with the change in switch cost (r = -0.602, p = 0.046). These findings suggest a close link between the up-regulation efficacy of FMT rhythms and goal-directed attentional control. In educational or clinical settings, it would be desirable to improve goal-directed attention through enhancement of FMT up-regulation efficacy of NFT in future work.
Changes in Negative Emotions Across Five Weeks of HRV Biofeedback Intervention were Mediated by Changes in Resting Heart Rate Variability
Resting heart rate variability (HRV) is typically higher in those with better emotional well-being. In the current study, we examined whether changes in resting HRV mediated changes in negative emotions during a 7-week clinical trial of HRV biofeedback. Younger and older adults were randomly assigned to one of two daily biofeedback practices for 5 weeks: (1) engage in slow-paced breathing to increase the amplitude of oscillations in heart rate at their breathing frequency (Osc+); or (2) engage in self-selected strategies to decrease heart rate oscillations (Osc-). We assessed negative emotion using the State Anxiety Inventory (SAI) and Profile of Mood States (POMS). Resting HRV at pre-intervention was significantly higher among those with lower negative emotion scores. Those participants showing greater increases in resting HRV showed greater decreases in negative emotion. In a mediation model with all participants, resting HRV changes significantly mediated the relationship between training performance (i.e., heart rate oscillation during practice sessions) and changes in negative emotion. However, additional analyses revealed this mediation effect was significantly moderated by condition and was only significant in the Osc+ condition. Thus, resting HRV changes mediated how biofeedback to increase amplitude of heart rate oscillations reduced negative emotion.
Mobile Heart Rate Variability Biofeedback for Work-Related Stress in Employees and the Influence of Instruction Format (Digital or Live) on Training Outcome: A Non-Randomized Controlled Trial
Work-related stress is a major health issue in most industrialized countries. Heart rate variability biofeedback (HRV-BfB) can promote resilience and stress coping capacity. Mobile HRV-BfB could contribute to stress prevention in the workplace. Little is known about whether the type of training, with digital or live instruction, has an impact on the training outcome. This study analyzes the psychophysiological effects of four-week workplace resilience training with mobile HRV-BfB and the influence of instruction format (digital or live) on training success. This was a prospective, three-arm, non-randomized controlled trial with parallel group design. 73 employees of a bearing and seal manufacturer (58.9% male, 86.3% full-time employment, 67.1% office workers) attended resilience training with HRV-BfB, live (n = 24) or digital (n = 19) format, or served as waitlist controls (n = 30). HRV-BfB training spanned four weeks. Participants applied resilience techniques to increase HRV using visual biofeedback. Data were collected at baseline (T0), post-intervention (T1), and another four weeks later (T2). Primary outcome measure was the Burnout scale of the Copenhagen Psychosocial Questionnaire (COPSOQ) at T1. Secondary outcome measures included further COPSOQ scales, self-reported sleep quality (Pittsburgh Sleep Quality Index, PSQI), and HRV parameters. Burnout parameters decreased significantly in HRV-BfB and waitlist. The decrease (T0-T1 and T0-T2) showed higher effect sizes in HRV-BfB (Cohen's d: 0.63; 0.69) than in waitlist (d: 0.27; 0.36). Sleep quality improved in HRV-BfB with small effect sizes (no change for waitlist). SDNN (standard deviation of beat-to-beat intervals) increased in HRV-BfB between T0 and T1 (d: 0.23;). In subgroup analysis, digital reached higher effect sizes for improvement in burnout (d: 0.87; 0.92) and sleep quality (d: 0.59; 0.64) than live learning (burnout: d: 0.43; 0.51; sleep quality: d: 0.28; 0.22). HRV-analysis revealed no differences between subgroups. Four-week mobile HRV-BfB resilience training reduced stress and burnout symptoms in employees. No significant differences were found between HRV-BfB digital or live. Hence, companies should choose the approach that fits their company profile or, if possible, offer both formats to accommodate the different needs of employees. However, findings were nonhomogeneous and should be verified by further studies.Trial Registration: ClinicalTrials.gov , NCT04897165, 05/18/2021, retrospectively registered.
The Importance of Including Psychophysiological Methods in Psychotherapy
This paper describes characteristics of sophisticated use of psychophysiological therapy procedures and describes a scoping review of evidence that adding psychophysiological procedures to psychotherapy improves outcome. It also reviews literature describing comparisons between psychophysiological procedures and various CBT and other verbal psychotherapy procedures when used as monotherapies. Some details of progressive muscle relaxation, autogenic training, and biofeedback are described that often are omitted in standard clinical training, including the method of diminishing tensions and differential relaxation training in progressive muscle relaxation, use of autogenic discharges and hypnotic instructions in autogenic training, and resonance frequency training in heart rate variability biofeedback and slow breathing. Although these details are often also missing in outcome studies, tentative conclusions can still be drawn from the empirical literature. As a monotherapy, psychophysiological methods are generally as powerful as verbal psychotherapies, although combining them with psychotherapy yields a larger effect than either approach alone. Psychophysiological methods have their strongest effects on anxiety and depression, with weaker effects for panic and PTSD, particularly when compared with exposure therapy, although the latter comparisons were restricted to relaxation training as a psychophysiological approach. Effects of psychophysiological interventions are weaker among elementary school children than among adults and adolescents. The results suggest that psychophysiological methods should be used along with other psychotherapeutic interventions for greatest effect.
Controlling Virtual Reality With Brain Signals: State of the Art of Using VR-Based Feedback in Neurofeedback Applications
The rapid progress of commercial virtual reality (VR) technology, open access to VR development software as well as open-source instructions for creating brain-VR interfaces have increased the number of VR-based neurofeedback (NF) training studies. Controlling a VR environment with brain signals has potential advantages for NF applications. More entertaining, multimodal and adaptive virtual feedback modalities might positively affect subjective user experience and could consequently enhance NF training performance and outcome. Nevertheless, there are certain pitfalls and contraindications that make VR-based NF not suitable for everyone. In the present review, we summarize applications of VR-based NF and discuss positive effects of VR-based NF training as well as contraindications such as cybersickness in VR or age- and sex-related differences. The existing literature implies that VR-based feedback is a promising tool for the improvement of NF training performance. Users generally rate VR-based feedback more positively than traditional 2D feedback, albeit to draw meaningful conclusions and to rule out adverse effects of VR, more research on this topic is necessary. The pace in the development of brain-VR synchronization furthermore necessitates ethical considerations on these technologies.
The Psychophysiological Relaxation Effects of Essential Oil Combined with Still-Life Painting Activities on Older Adults in Taiwan During the COVID-19 Pandemic
Although the COVID-19 pandemic affected all types of people, older adults were disproportionately affected. Therefore, we developed an indoor program inspired by art and natural elements (plant essential oils [EOs]) intended to have a relaxing effect akin to a forest atmosphere to enhance psychophysiological health during this period. Thirty Taiwanese older adults (range, 59-79 years) participated in the study. We combined an art activity (still-life painting of vegetables) with the inhalation of Pseudotsuga menziesii and Lavandula angustifolia EOs during a 100-minute experiment. The study showed that physiological measures (heart rate, normalized low-frequency heart variability, the ratio of low- to high-frequency heart variability, high-beta waves, and gamma waves) decreased during the experiment; correspondingly, increased standard deviation of normal-to-normal intervals, normalized high-frequency heart variability, and high-alpha waves were observed, indicating relaxed physiological state. Subjective psychological assessments using the State-Trait Anxiety Inventory-State showed lower posttest scores, further supporting the relaxation effects. The psychophysiological data from this study provide important scientific evidence for the physical and mental health benefits of indoor nature-based activity programs for older adults, thereby improving their quality of life.
Yoga for Psychophysiological Wellbeing during Menstrual Phases in Eumenorrheic Females
Hormonal shifts during the menstrual cycle (MC) cause autonomic imbalances and psycho-physiological distress in eumenorrheic females. This present study reveals that yoga proactively improves the overall psychophysiological health and wellness in eumenorrheic female college students during different phases of MC. Healthy eumenorrheic female college students (M= 20.11 ± 5.39 years, n = 82) were randomized to a control and yoga group (n = 41). A well-conceptualized yoga module (CYM) for 5 days/week for 3 months (1 h daily in the morning) was practiced by the yoga group volunteers. Intra and intergroup comparisons were performed for the estimation of mindfulness awareness scale (MAAS), menstrual distress questionnaire (MDQ), cardiometabolic risk factors, heart rate variability (HRV), and endurance fitness during the luteal (LP) and follicular (FP) phases. Psychophysiological discomforts before CYM practice were mostly observed during LP compared to FP due to significant changes in mindfulness, pain, concentration, autonomic reactivity, negative affect, double product (DoP), rate pressure product (RPP), and HRV values. CYM practice influenced HRV parameters for an increase in parasympathetic activity and a decrease in sympathetic balance for better cardiac-autonomic functioning, with significant improvement in maximal oxygen consumption (VO) and physical work capacity (PWC). Accordingly, MAAS and MDQ scores also improved significantly after yogic practice. The intra-group and inter-group significant improvements in psychophysiological parameters through CYM practice are relevant in eumenorrheic females to perform effectively throughout their MC period, by improving MC distress and sympathovagal (LF/HF) balance.
Can HRV Biofeedback Training Improve the Mental Resilience of Icelandic Police Officers?
High heart rate variability (HRV) is increasingly recognized as an indicator of a healthy regulatory system, reflecting the dynamic balance between sympathetic (SNS) and parasympathetic (PSNS) nervous system activity. According to the neurovisceral integration model, this balance is managed by the central autonomic network (CAN), comprised of specific brain regions involved in emotional, attentional, and autonomic regulation. HRV thus reflects the performance of the cognitive, affective, and autonomic regulation system. Numerous studies support the relationship between HRV and the CAN, including research on HRV biofeedback training (HRVBF). Studies on the effectiveness of HRVBF for professions such as police officers have shown improvements in self-regulation, decision-making, and performance. However, few studies have specifically explored HRVBF's influence on HRV metrics in police officers, highlighting a need for further research. This study addresses this gap by randomly assigning 27 Icelandic police officers to intervention or wait-list control groups. The intervention group underwent a five-week HRVBF program, including group and individual training sessions. Results showed significant increases in HRV metrics for the intervention group, indicating improved autonomic function and stress resilience. Mental resilience increased significantly as measured by subjective measures of attentional control, mindful awareness, and reduced fatigue. These findings support the efficacy of HRVBF in enhancing HRV and mental resilience for police officers, suggesting its applicability and potential for integration into existing training programs.
Effects of Heart Rate Variability (HRV) Biofeedback in Pulmonary Indicators and HRV Indices Among Patients with Chronic Obstructive Pulmonary Disease
Patients with chronic obstructive pulmonary disease (COPD) exhibit reduced cardiac autonomic activity, linked to poor prognosis and exercise intolerance. While heart rate variability biofeedback (HRVB) can enhance cardiac autonomic activity in various diseases, its use in patients with COPD is limited. This study explored the impact of the HRVB on cardiac autonomic activity and pulmonary indicators in patients with COPD. Fifty-three patients with COPD were assigned to either the HRVB (n = 26) or the control group (n = 27), with both groups receiving standard medical care. The HRVB group also underwent one-hour HRVB sessions weekly for six weeks. All participants had pre- and post-test measurements, including the Six-Minute Walking Test (6MWT), lead II electrocardiogram (ECG) recording, Modified Medical Research Council Dyspnea Scale (mMRC), body mass index, airflow obstruction, dyspnea, and exercise capacity (BODE) index. ECG data were analyzed for heart rate variability (HRV) as an index of cardiac autonomic activity. A two-way mixed analysis of variances demonstrated significant interaction effects of Group × Time in pulmonary indicators and HRV indices. The HRVB group exhibited significant post-test improvements, with decreased mMRC and BODE scores and increased 6MWT distance and HRV indices, compared to pre-test results. The 6MWT distance significantly increased and mMRC significantly decreased at post-test in the HRVB group compared with the control group. This study confirmed the efficacy of HRVB as an adjunct therapy in patients with COPD, showing improvements in exercise capacity, breathing difficulties, and cardiac autonomic activity.
Effect of Heart Rate Variability Biofeedback on Cardiac Autonomic Activation and Diabetes Self-Care in Patients with Type II Diabetes Mellitus
In type 2 diabetes mellitus (T2DM), decreased autonomic activation and heightened negative emotions may worsen glycemic control. This study investigated the effects of heart rate variability biofeedback (HRVB) on autonomic activation, negative emotions, diabetes self-care, and glycemic control in patients with T2DM. A total of 61 participants with T2DM were assigned to either the HRVB group (n = 30; 62.67 ± 7.28 years; 14 females) or the control group (n = 31; 63.39 ± 6.96 years; 14 females). Both groups received the treatment as usual, and the HRVB group received 60 min of HRVB sessions weekly for 6 weeks. Participants completed psychological questionnaires, a resting electrocardiogram (ECG), and breathing rate assessments at pre- and post-tests. Heart rate variability (HRV) indices were derived from ECG data, and glycated hemoglobin (HbA1c) levels were collected from the electronic medical records. The analysis revealed significant Group × Time interaction effects on HRV indices, breathing rate, depression symptoms, and diabetes self-care behavior. The HRVB group demonstrated higher HRV indices, lower breathing rate, and improved diabetes self-care behavior compared to the control group. Moreover, the HRVB group showed enhanced HRV indices and diabetes self-care behavior, as well as reduced breathing rate and depression in the post-test compared to the pre-test. However, there was no significant interaction effect on HbA1c levels. Six sessions of HRVB proved effective as a complementary therapy for T2DM, enhancing HRV indices, alleviating depressive symptoms, and promoting better diabetes self-care behaviors.
Individualized EEG-Based Neurofeedback Targeting Auditory Steady-State Responses: A Proof-of-Concept Study
Gamma-band (> 30 Hz) brain oscillatory activity is linked with sensory and cognitive processes and exhibits abnormalities in neuropsychiatric disorders. Therefore, neuromodulation techniques targeting gamma activity are being developed. One promising approach is neurofeedback (NFB) which is based on the alteration of brain responses via online feedback. However, the existing gamma-based NFB systems lack individualized approach. In the present work, we developed and tested an individualized EEG-NFB system. 46 healthy volunteers participated in three sessions on separate days. Before NFB training, individual gamma frequency (IGF) was estimated using chirp-modulated auditory stimulation (30-60 Hz). Participants were subjected to IGF-increase (if IGF was ≤ 45 Hz) or IGF-decrease conditions (if IGF was > 45 Hz). Gamma-band responses were targeted during NFB training, in which participants received auditory steady-state stimulation at frequency slightly above or below IGF and were instructed to try to increase their response while receiving real-time visual feedback. Each time a pre-defined response goal was reached, stimulation frequency was either increased or decreased. After training, IGF was reassessed. Experimental group participants were divided into equal groups based on the median success rate during NFB training. The results showed that high-responders had a significantly higher IGF modulation compared to control group, while low-responders did not differ from controls. No differences in IGF modulation were found between sessions and between NFB repetitions in all participant groups. The initial evaluation of the proposed EEG-NFB system showed potential to modulate IGF. Future studies could investigate longer-lasting electrophysiological and behavioural effects of the application of ASSR/IGF-based NFB system in clinical populations.
"Your Thoughts are (were) Free!": Brain-Computer-Interfaces, Neurofeedback, Detection of Deception, and the Future of Mind-Reading
This review describes the historical developement and rationale of clinically relevant research on neurophysiological "mind reading" paradims: Brain- Computer-Interfaces, detection of deception, brain stimulation and neurofeedback and the clinical applications in drug resistant epilepsy, chronic stroke, and communication with paralyzed locked-in persons. The emphasis lies on completely locked-in patients with amyotrophic lateral sclerosis using non-invasive and invasive brain computer interfaces and neurofeedback to restore verbal communication with the social environment. In the second part of the article we argue that success and failure of neurophysiological "mind reading" paradigms may be explained with a motor theory of thinking and emotion in combination with learning theory. The ethical implications of brain computer interface and neurofeedback approaches, particularly for severe chronic paralysis and loss of communication diseases and decisions on hastened death and euthanasia are discussed.