A Randomized Sham-Controlled Trial of Heart Rate Variability Biofeedback Following Traumatic Brain Injury (TBI).

Objective Autonomic nervous system dysregulation is a common consequence of traumatic brain injury (TBI). Heart rate variability (HRV) is a cost-effective measure of autonomic nervous system functioning, with studies suggesting decreased HRV following moderate-to-severe TBI. HRV biofeedback treatment may improve post-TBI autonomic nervous system functioning and post-injury emotional and cognitive functioning. We provide a systematic evidence-based review of the state of the literature and effectiveness of HRV biofeedback following TBI. Method We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Two coders coded each article and provided quality ratings. Seven papers met inclusion criteria. All studies included a measure of emotional functioning and 5 studies (63%) included neuropsychological outcomes. Results Participants completed 11 sessions of HRV biofeedback on average (range = 1 to 40). HRV biofeedback was associated with improved HRV following TBI. There was a positive relationship between increased HRV and TBI recovery following biofeedback, including improvements in cognitive and emotional functioning, and physical symptoms such as headaches, dizziness, and sleep problems. Conclusion The literature on HRV biofeedback for TBI is promising, but in its infancy; effectiveness is unclear due to poor-to-fair study quality, and potential publication bias (all studies reported positive results).

Patients with coronary artery disease (CAD) often experience anger events before cardiovascular events. Anger is a psychological risk factor and causes underlying psychophysiological mechanisms to lose balance of the autonomic nervous system (ANS). The heart rate variability (HRV) was the common index for ANS regulation. It has been confirmed that heart rate variability biofeedback (HRV-BF) restored ANS balance in patients with CAD during the resting state. However, the effects of HRV-BF during and after the anger event remain unknown. This study aimed to examine the effects of HRV-BF on ANS reactivity and recovery during the anger recall task in patients with CAD. This study was a randomized control trial with a wait-list control group design, with forty patients in the HRV-BF group (for six sessions) and 44 patients in the control group. All patients received five stages of an anger recall task, including baseline, neutral recall task, neutral recovery, anger recall task, and anger recovery. HRV reactivity in the HRV-BF group at the post-test was lower than that in the control group. HRV recovery at the post-test in the HRV-BF group was higher than that in the control group. The HRV-BF reduced ANS reactivity during anger events and increased ANS recovery after anger events for CAD patients. The possible mechanisms of HRV-BF may increase total HRV, ANS regulation, and baroreflex activation at anger events for patients with CAD, and may be a suitable program for cardiac rehabilitation.

The Use of Heart Rate Variability Biofeedback and Neurofeedback for Traumatic Brain Injury

ContextSports related concussions (SRC), occur frequently in contact and collision sports and detection relies predominantly on subjective reports by athletes themselves. A non-invasive means of monitoring brain function and injury is desirable. Existing literature has established autonomic nervous system (ANS) dysfunction in the setting of brain injury. Heart rate variability (HRV) has been accepted as a means of measuring ANS function and correlation of ANS dysregulation after brain injury through HRV measurement can aid in the detection of concussions, monitoring of recovery, and may offer a target for intervention.MethodsThe studies included were found on the Ovid MEDLINE, PubMed, and Google Scholar databases through searches of the following keywords: HRV, heart rate variability and concussion, post-concussion syndrome, and HRV biofeedback. We excluded studies that were not in English and did not meet the inclusion criteria of pertaining to SRC, sports performance, or ANS function.DesignClinical review.ResultsCurrent literature supports the notion that SRC causes dysregulation of the ANS, which can be detecting through changes in HRV. Monitoring HR and analyzing HRV can be used as a tool to detect SRC, monitor recovery, and set a target for treatment. Biofeedback techniques targeting HRV have been used to improve HRV and expedite recovery from SRC.ConclusionExisting literature has shown HRV is a tool for concussion detection and HRV biofeedback can aid in recovery. More rigorous study of the best ways to measure HRV in athletes, qualify and quantify changes in HRV specific to SRC, timing of change, timing of resolution of ANS dysfunction, and clinical significance of persistent HRV change after injury were all identified as targets for future research. Interventional studies evaluating the use of biofeedback as a means of improving HRV and reducing concussion symptoms severity and duration are warranted as well.

Introduction and Purpose:Rigorous training of elite athletes can lead to nonfunctional overreaching (NFOR) and overtraining (OT), both of which decrease performance and increase the risk of injury. Heart rate variability (HRV) is a measure of autonomic nervous system balance. Reductions in HRV are associated with NFOR and OT. Breath-based biofeedback increases HRV through activation of the baroreceptor reflex.Purpose:This case study explored the impact of breath-based HRV biofeedback (HRV-BF) training on daily resting HRV values of a female triathlete and the association between daily HRV with subjective performance indicators of workout quality and amount of postworkout energy.Methods:A 24-year-old female triathlete completed an 8-week A-B repeated-measures study—A: baseline; 4 weeks and B: intervention HRV-BF training; 4 weeks. The subject recorded daily resting HRV for 120 seconds, completed regular daily training, and measured workout performance and postworkout energy levels on a 0 to 10 scale. During B, the subject added 15 minutes of HRV-BF 5 times per week.Results:With HRV-BF, median HRV level increased (A: 137; B: 191) and the interquartile band narrowed (A: 83–184; B: 142–201), suggesting higher HRV with less variability. The subject had more days at highest readiness (A: 35%; B: 62%). Median values for reports of workout performance and postworkout energy increased.Conclusions:This study found that, for this subject, 15 minutes of HRV-BF, 5 times per week, was associated with increased HRV and improved subjective workout performance. Further research exploring HRV measures and biofeedback to inform athletic performance is warranted.

Heart rate variability (HRV) may provide an index of capacity for social functioning and may be remediated by HRV biofeedback. Given reductions in HRV are found following traumatic brain injury (TBI), the present study aimed to determine whether lower HRV in TBI is associated with social function, and whether HRV biofeedback might be a useful remediation technique in this population. Resting state HRV and measures of social and emotional processing were collected in 30 individuals with severe TBI (3–34 years post-injury) and 30 controls. This was followed by a single session of HRV biofeedback. HRV was positively associated with social cognition and empathy, and negatively associated with alexithymia for the TBI group. Both TBI and control groups showed significantly increased HRV on both time-domain (i.e., SDNN, rMSSD) and frequency-domain measures (LF, HF, LF:HF ratio) during biofeedback compared to baseline. These results suggest that decreased HRV is linked to social and emotional function following severe TBI, and may be a novel target for therapy using HRV biofeedback techniques.

Although psychological factors have been implicated in patients with functional dysphonia (FD), conventional voice therapy (CVT) typically targets the aberrant voice symptoms exclusively. Yet, CVT is not always successful, and in view of the significant adverse quality of life impact combined with the financial burden on the healthcare system and society, research is needed to elucidate the underlying psychophysiology of FD and improve treatment outcomes. The first objective of this research project is to compare the occurrence and frequency of symptoms and/or disorders related to autonomic nervous system (ANS) dysfunction in patients with FD with gender- and age-matched vocally healthy controls, using a case-control study. The second objective is to compare the effects of a novel therapy for FD based on ANS regulation (i.e., ANS therapy: heart rate variability (HRV) biofeedback) on both autonomic function and voice function versus CVT alone or in combination with ANS therapy (i.e., ANS therapy + CVT), using a randomized controlled trial (RCT). Case-control study: Autonomic (dys)function of patients with FD will becompared with gender- and age-matched vocally healthy controls, using both physiological measures (e.g., HRV, skin conductance level) and psychological patient-reported outcome measures (PROMs, e.g., Neuroception of Psychological Safety Scale, Depression Anxiety and Stress Scale). RCT: The FD group will be randomly assigned to the innovative ANS therapy group, the CVT group or the ANS therapy + CVT group. All patients received 1 month of treatment with 20 min of daily practice. Both the autonomic assessment and the voice assessment will beperformed pretherapy and immediately after therapy by assessors blinded to group allocation and study phase. Higher occurrences of symptoms and/or disorders related to autonomic dysfunction are expected in patients with FD compared with vocally healthy controls. Physiological outcomes: lower HRV, lower cardiac pre-ejection period, higher respiration rate and higher skin conductance level are hypothesized in patients with FD compared with vocally healthy controls. Psychological PROMs: higher self-report of feelings/symptoms related to autonomic dysfunction (e.g., perceived stress, anxiety) is expected in patients with FD compared with vocally healthy controls. The autonomic function is hypothesized to improve more after the ANS therapy and the ANS therapy + CVT compared with the CVT only. Voice function is expected to improve more after the ANS therapy + CVT compared with the ANS therapy and the CVT alone. What is already known on the subject Autonomic dysfunction is well recognized in the field of psychology but remains understudied in the area of voice. Given that the vagus nerve, innervating the larynx, also helps to regulate the ANS, and psychological symptoms commonly observed in patients with FD may reflect ANS dysregulation, research in this area is needed. There is some preliminary evidence that autonomic dysfunction might indeed be associated with FD. However, physiological ANS measures are needed, as well as validated psychological PROMs. What this paper adds to the existing knowledge The first objective of this study is to investigate the occurrence and frequency of symptoms and/or disorders related to autonomic dysfunction in patients with FD as compared with a gender- and age-matched vocally healthy control group. Autonomic (dys)function will be determined by employing both physiological measures (e.g., HRV, skin conductance level) and psychological PROMs (e.g., Neuroception of Psychological Safety Scale, Depression Anxiety and Stress Scale). The second objective is to compare the effects of a novel therapy for FD based on ANS regulation (HRV biofeedback) versus CVT alone or in combination with ANS therapy. What are the potential or actual clinical implications of this work? Success rates of symptomatic CVT for FD are highly variable. This study is expected to lead to innovative results related to the pathogenesis and psychophysiology of FD, a prevalent voice disorder associated with a significant adverse quality of life impact and a substantial financial burden on the healthcare system and society. The results of this study will lead to crucial new insights into both the diagnosis and treatment of FD, contributing to evidence-based practice in the field of voice.

This paper discusses the clinical applications of heart rate variability (HRV) data in the treatment of clients who have experienced traumatic brain injuries (TBIs). In the authors' clinical practice, HRV data is collected at the initial assessment, at progress assessments, and again after the completion of a course of neurofeedback combined with HRV biofeedback treatment. This paper describes HRV seen in healthy individuals compared to HRV in individuals known to have experienced a TBI. Three clinical case examples are discussed that explore the changes in heart rate variability following traumatic brain injury as well as improvements noted during, and following, a course of neurofeedback combined with HRV biofeedback training. The cases illustrated in this paper demonstrate the impressive changes in heart rate variability that can occur following a traumatic brain injury and also highlight how neurofeedback combined with biofeedback training can be used to improve heart rate variability and ameliorate related cognitive symptoms.

Heart rate variability (HRV) biofeedback (BFB) can be used to reduce activation of the sympathetic nervous system (SNS) and increase activation of the parasympathetic nervous system (PNS). A growing body of research suggests that increased arousal of the SNS contributes to the sustained state of postconcussion syndrome (PCS). It has also been postulated that underactivation of the PNS may also play a role in the postinjury state of autonomic dystonia, wherein the autonomic nervous system is in a state of imbalance and does not return to normal. In addition to autonomic imbalance, patients who are generally advised not to engage in physical exertion until asymptomatic from concussion, are known to experience secondary symptoms of fatigue and reactive depression. Recent research has established that such symptoms can delay the recovery from concussion indefinitely. By addressing both autonomic dysfunction and the secondary symptoms of depression and anxiety, HRV BFB may be an effective treatment for PCS by strengthening self-regulatory control mechanisms in the body and improving autonomic balance. Recent studies have suggested that HRV BFB has a positive impact in reducing stress and anxiety among athletes, and concussed athletes with higher perceived control over their symptoms have been shown to have faster recoveries post-injury. The primary purpose of the following case study was, therefore, to assess the feasibility of implementing HRV BFB with a concussed athlete suffering from postconcussion syndrome (PCS). The second objective was to prospectively examine the impact of ten weeks of HRV biofeedback on refractory postconcussion symptoms. During this pilot case study, the athlete attended 10 weekly sessions of HRV BFB, according to the protocol set forth by Lehrer, Vaschillo, and Vaschillo (2000). After 10 weeks of HRV biofeedback, the athlete exhibited clinically significant improvements in total mood disturbance, postconcussion symptoms, and headache severity. The results suggest that HRV BFB may be a useful adjunctive treatment for PCS, associated with increases in HRV and enhanced cardiovagal activity. Given these findings, a randomized controlled trial is warranted.

Introduction: In patients with acute ischaemic stroke (AIS) dysregulation of cardiac function with decreased heart rate variability (HRV) due to impaired integrity of the autonomic nervous system is a frequent complication which is associated with increased mortality and worsening of clinical outcome. HRV biofeedback has previously been suggested to improve cardiac autonomic function by increasing parasympathetic tone. Hypothesis: We hypothesized that HRV biofeedback can be used to complement stroke unit care and alleviate autonomic cardiac dysfunction following AIS. Methods: We randomly allocated patients with AIS to either receive 9 sessions of HRV (n=24) or sham (n=24) biofeedback in addition to standard stroke unit care. These patients underwent detailed assessment of autonomic cardiac function including analysis of HRV via standard deviation of NN intervals (SDNN) and spectral analysis. Furthermore, we assessed vasomotor and sudomotor autonomic function, severity of autonomic symptoms and neurological and functional outcomes. Results: We included 48 patients (19 females, ages 65±14 years, baseline NIHSS 2.2 ± 2.2, mean ± standard deviation). Patients who had undergone HRV biofeedback displayed improved cardiac function compared to baseline (SDNN 72.6 ± 52.4 ms vs. 45.5 ± 34.7 ms, p<0.01) which was not seen in those who received sham biofeedback (p=ns). Similar changes were seen on spectral analysis measures of parasympathetic function (p<0.01). Improvement of autonomic cardiac function following HRV biofeedback was paralleled by decreased severity of autonomic symptoms (p<0.05). Contrasting our observation of an increase in predominantly parasympathetic parameters such as CVNN, sympathetic measures of sudomotor and vasomotor function remained unchanged in both groups (p=ns). Neurological and functional outcomes were unchanged immediately post intervention, however 3-month follow up is yet to be completed. Discussion: HRV biofeedback can modulate autonomic cardiac function post AIS to increase HRV and alleviate autonomic symptoms which might be beneficial in facilitating recovery from functional impairment. This seems to be mediated by a predominantly parasympathetic mechanism of action.

Some individuals with panic disorder (PD) display reduced heart rate variability (HRV), which may result in an increased risk of cardiovascular mortality. Heart rate variability-biofeedback (HRV-BF) training has been shown to improve the modulation of the autonomic activity. Therefore, this randomized controlled trial was conducted to investigate the effect of a 4-week HRV-BF intervention in individuals with PD. HRV-BF training improved the modulation of the autonomic activity. Therefore, with this randomized controlled trial, we aimed to investigate the effect of a 4-week HRV-BF intervention in people with PD. Thirty-six women and 16 men with PD (mean age = 35.85 [15.60] years) were randomly allocated either to HRV-BF with 0.1-Hz breathing as intervention group or to HRV-Sham-BF as active control group. HRV-BF was performed for 4 weeks, whereas HRV was measured both during a short-term resting condition and during a paced breathing condition before and after intervention. HRV-BF with 0.1-Hz breathing increased HRV and reduced panic symptoms in individuals with PD. HRV-BF with 0.1-Hz breathing demonstrated an increase in the time and frequency domain parameters of HRV during the short-term resting condition (ΔPost-Pre root mean square successive differences: 5.87 [14.03] milliseconds; ΔPost-Pre standard deviation of all NN intervals: 11.63 [17.06] milliseconds; ΔPost-Pre total power: 464.88 [1825.47] milliseconds2; ΔPost-Pre power in low-frequency range 0.04-0.15 Hz: 312.73 [592.71] milliseconds2), a decrease in the heart rate during the paced breathing condition (ΔPost-Pre: -5.87 [9.14] beats/min), and a decrease in the Panic and Agoraphobia Scale (ΔPost-Pre: -3.64 [6.30]). There was no intervention effect in the HRV-Sham-BF group. HRV-BF as a noninvasive and nonpharmacological treatment seems to be an important intervention option to improve reduced HRV and decrease panic symptoms in individuals with PD. Future studies are needed to establish whether these effects translate to reductions in the risk of cardiovascular disease in PD.

Objectives Insomnia often involves physiological hyperarousal, particularly autonomic dysregulation. Although Cognitive Behavioral Therapy for Insomnia (CBT-I) is effective, some patients do not achieve complete remission. This preliminary study evaluated whether combining CBT-I with heart rate variability (HRV) biofeedback could enhance treatment effects by improving autonomic regulation. Methods Forty-four adults with insomnia were randomized to either a CBT-I group or a combined group that received HRV biofeedback (HRV-BF) and CBT-I (CBT-I+BF group). Both groups received seven weekly CBT-I sessions, with HRV-BF introduced in session four in the CBT-I+BF group. The primary outcome measure was the Insomnia Severity Index (ISI). Other outcome measures included the Pre-Sleep Arousal Scale (PSAS), sleep diaries, and HRV metrics. Assessments were conducted at baseline, post-treatment, and six-month follow-up. ISI and PSAS were also assessed at week 4 before the introduction of HRV-BF. Results Both groups significantly improved in insomnia severity, pre-sleep arousal, and some sleep diary variables.The CBT-I+BF group showed unique and significant improvement in subjective total sleep time. While overall autonomic balance only showed a trend-level improvement in the CBT-I+BF group, sensitivity analyses on participants with more severe objective sleep disturbance suggested greater autonomic balance improvement for the CBT-I+BF group. Conclusions Incorporating HRV-BF into CBT-I did not significantly enhance the benefits of CBT-I alone in this study. However, it offers additional advantages for individuals with more objective sleep disturbance, particularly in improving autonomic balance. Future research should identify optimal treatment intensity and explore the utility of HRV-BF in various insomnia sub-populations.

Heart rate variability (HRV) biofeedback is often performed with structured education, laboratory-based assessments, and practice sessions. It has been shown to improve psychological and physiological function across populations. However, a means to remotely use and monitor this approach would allow for wider use of this technique. Advancements in wearable and digital technology present an opportunity for the widespread application of this approach. The primary aim of the study was to determine the feasibility of fully remote, self-administered short sessions of HRV-directed biofeedback in a diverse population of health care workers (HCWs). The secondary aim was to determine whether a fully remote, HRV-directed biofeedback intervention significantly alters longitudinal HRV over the intervention period, as monitored by wearable devices. The tertiary aim was to estimate the impact of this intervention on metrics of psychological well-being. To determine whether remotely implemented short sessions of HRV biofeedback can improve autonomic metrics and psychological well-being, we enrolled HCWs across 7 hospitals in New York City in the United States. They downloaded our study app, watched brief educational videos about HRV biofeedback, and used a well-studied HRV biofeedback program remotely through their smartphone. HRV biofeedback sessions were used for 5 minutes per day for 5 weeks. HCWs were then followed for 12 weeks after the intervention period. Psychological measures were obtained over the study period, and they wore an Apple Watch for at least 7 weeks to monitor the circadian features of HRV. In total, 127 HCWs were enrolled in the study. Overall, only 21 (16.5%) were at least 50% compliant with the HRV biofeedback intervention, representing a small portion of the total sample. This demonstrates that this study design does not feasibly result in adequate rates of compliance with the intervention. Numerical improvement in psychological metrics was observed over the 17-week study period, although it did not reach statistical significance (all P>.05). Using a mixed effect cosinor model, the mean midline-estimating statistic of rhythm (MESOR) of the circadian pattern of the SD of the interbeat interval of normal sinus beats (SDNN), an HRV metric, was observed to increase over the first 4 weeks of the biofeedback intervention in HCWs who were at least 50% compliant. In conclusion, we found that using brief remote HRV biofeedback sessions and monitoring its physiological effect using wearable devices, in the manner that the study was conducted, was not feasible. This is considering the low compliance rates with the study intervention. We found that remote short sessions of HRV biofeedback demonstrate potential promise in improving autonomic nervous function and warrant further study. Wearable devices can monitor the physiological effects of psychological interventions.

Low heart rate variability (HRV) characterizes several medical and psychological diseases. HRV biofeedback is a newly developed approach that may have some use for treating the array of disorders in which HRV is relatively low. This review critically appraises evidence for the effectiveness of HRV and related biofeedback across 14 studies in improving (1) HRV and baroreflex outcomes and (2) clinical outcomes. Results revealed that HRV biofeedback consistently effectuates acute improvements during biofeedback practice, whereas the presence of short-term and long-term carry-over effects is less clear. Some evidence suggests HRV biofeedback may result in long-term carry-over effects on baroreflex gain, which is an area most promising for future investigations. On the other hand, concerning clinical outcomes, there is ample evidence attesting to efficacy of HRV biofeedback. However, because clinical and physiological outcomes do not improve concurrently in all cases, the mechanism by which HRV biofeedback results in salutary effects in unclear. Considerations for the field in addressing shortcomings of the reviewed studies and advancing understanding of the way in which HRV biofeedback may improve physiological and clinical outcomes are offered in light of the reviewed evidence.

Biofeedback is 1 form of complementary therapy commonly used to treat pediatric chronic pain. Given the limited research in biofeedback treatment outcomes with youth experiencing chronic pain, the present study sought to initially examine the potential for heart rate variability (HRV) biofeedback to support self-regulation training for adolescents participating in a chronic pain rehabilitation program. Using a case series design, this study examined changes in HRV and respiration rate for 4 adolescents with chronic pain. Adolescents completed an initial assessment followed by 3–4 biofeedback training sessions. The Nexus 10 biofeedback system (BioTrace+ software) was used to obtain respiration rate and HRV low-frequency percentage. Visual inspection of plotted graphs from adolescents’ HRV biofeedback training demonstrated (a) improved cardiopulmonary functioning across sessions during active training, (b) changed cardiopulmonary functioning across sessions during baseline assessment, and (c) improved functioning without active feedback, suggesting self-regulation of cardiopulmonary functioning. Adolescents using a brief protocol of HRV biofeedback training demonstrated expected changes in cardiopulmonary functioning and self-regulation. Similar to findings in adults, HRV biofeedback yields promise as an intervention to treat children with chronic pain and comorbid symptoms. However, because this is an initial study, additional research with more rigorous methodology is needed to further support the benefit of HRV biofeedback in modifying physiological awareness and self-regulation and the connection of this self-regulation with clinical outcomes. Future clinical research should build on these initial findings to develop and test biofeedback protocols to treat chronic pain in children. Implications for Impact Statement Findings from this case series design showed initial benefits in increasing adolescents’ physiological self-regulation skills. Providers may draw clinical applications from these self-regulation techniques within and outside of a biofeedback context to teach increased awareness, control, and generalization of self-regulatory skills to cope with negative experiences.