History and Recent Advances of the Japanese Society of Biofeedback Research.

This article provides an overview of the history of the Japanese Society of Biofeedback Research (JSBR) and presents some of its recent advances. Most of the research papers published in the JSBR journal (Biofeedback Kenkyu) have been written in Japanese, and therefore have had very few opportunities to reach global readers. We would like to present some of important findings previously published there. First, we present the history of the JSBR. Secondly, we will focus on paced breathing, which is instrumental in achieving relaxation in heart rate variability biofeedback (HRV-BF). We will look back on the origin of slow-paced breathing in Japan, that could be attributed to the concept of Tanden breathing (abdominal paced breathing) practiced in Zen meditation. Thirdly, we will introduce some of the current research progresses of JSBR, especially focusing on the development of a non-contact sensing technology and relaxation device. Finally, we will explain about a very recent trial, the "Suu-Haa" Relaxation Technique, which we hope may be useful for helping people cope with the SARS-CoV-2 (COVID-19) crisis.

Efficacy of Paced Breathing at the Low-frequency Peak on Heart Rate Variability and Baroreflex Sensitivity.

We developed a simple method for identifying resonance frequency by focusing on the spectral peak of the low-frequency (LF) component of heart rate variability (HRV) and examined the hypothesis that paced breathing at an accurate resonance frequency increases HRV and baroreflex sensitivity (BRS). We assessed a peak frequency of the LF component of the resting HRV by using power spectral analysis under respiratory control at 0.25 Hz, and a resonance frequency, which was evaluated by using the standard breathing maneuver (Lehrer 2007). We examined the effects of paced breathing at the peak frequency of the LF component (Spectral condition) and paced breathing at the resonance frequency as determined by the standard breathing maneuver (Standard condition) on HRV and BRS in 28 healthy college students and young adults. Electrocardiogram, respiration, and noninvasive continuous blood pressure was recorded during a 5-min baseline, followed by a 5-min paced breathing session. Results indicated that the BRS increased during the breathing session under both conditions, but the increase in BRS under the Spectral condition was higher than the Standard condition (p < .05). The LF amplitude increased during the breathing session under both conditions (p < .001), although the difference between the conditions was not significant. These results suggest that paced breathing at the peak frequency of the LF component enhanced the autonomic baroreflex function. Moreover, assessment of the LF-peak may provide more accurate information on resonance frequency for paced breathing during HRV biofeedback.

A Significant Association of Malnutrition with Dysphagia in Acute Patients.

Dysphagia and malnutrition seem to be associated, but little research in detail has been reported. We aimed to clarify the association between dysphagia and malnutrition by adopting accurate diagnosis and mathematical evaluation of dysphagia using videofluorography and nutritional assessment calculated by a well-established nutritional risk index. We conducted a retrospective analysis of 165 enrolled patients who were admitted to our hospital for acute diseases and underwent videofluorography on suspicion of dysphagia in the year 2016. We diagnosed high-risk dysphagia in patients with 8-point penetration-aspiration scale (PAS) score over 4. We used the geriatric nutritional risk index (GNRI) as a nutritional assessment tool. A GNRI score less than 91.2 corresponds to malnutrition. The median age of 165 enrolled patients was 76.0, and the number of female patients was 53. The mean GNRI was 81.2, and 134 patients (81.2%) had malnutrition. The number of the patients with a diagnosis of high-risk dysphagia was 54 (32.7%). The GNRI of patients with high-risk dysphagia was significantly less than that of patients without (mean value 77.7 ± 10.5 vs. 83.0 ± 10.5, P = 0.003). GNRI < 91.2 was independently and significantly associated with high-risk dysphagia (OR 3.094; CI 1.057-9.058; P = 0.039). Based on the current study, the authors propose evaluating nutritional status to predict dysphagia risk of patients in the acute phase.

Heart rate variability biofeedback improves cardiorespiratory resting function during sleep.

The present study was designed to examine the effect of heart rate variability (HRV) biofeedback on the cardiorespiratory resting function during sleep in daily life. Forty-five healthy young adults were randomly assigned to one of three groups: HRV biofeedback, Autogenic Training(AT), and no-treatment control. Participants in the HRV biofeedback were instructed to use a handheld HRV biofeedback device before their habitual bedtime, those in the AT were asked to listen to an audiotaped instruction before bedtime,and those in the control were asked to engage in their habitual activity before bedtime. Pulse wave signal during sleep at their own residences was measured continuously with a wrist watch-type transdermal photoelectric sensor for three time points. Baseline data were collected on the first night of measurements, followed by two successive nights for HRV biofeedback, AT, or control. Cardiorespiratory resting function was assessed quantitatively as the amplitude of high frequency(HF) component of pulse rate variability, a surrogate measure of respiratory sinus arrhythmia. HF component increased during sleep in the HRV biofeedback group,although it remained unchanged in the AT and control groups. These results suggest that HRV biofeedback before sleep may improve cardiorespiratory resting function during sleep.

Voluntarily produced increases in heart rate variability modulate autonomic effects of endotoxin induced systemic inflammation: an exploratory study.

Exposure of healthy people to lipopolysaccharide (LPS; endotoxin) produces a pro-inflammatory response, subjective symptoms, and decreased heart rate variability (HRV). Given the efficacy of HRV biofeedback (BF) for treating asthma, the large autonomic effects of HRV BF, and the link between vagus nerve activity and inflammation, we hypothesized that HRV BF would dampen the acute manifestations of systemic inflammation induced by LPS challenge. Healthy participants age 18-40 were randomly assigned to four-one-hour training sessions of either HRV BF (n = 6) or a control 15/min paced breathing condition (n = 5) prior to acute experimentally induced LPS exposure. Participants were coached to do the procedures for 10 min each at five hourly time points after LPS injection, and then 2 h later. Subjective symptoms, HRV parameters, and plasma cytokine levels were measured at each time point, 2 h afterward, and the following morning. Participants were able to perform the procedures both during four pre-exposure training sessions and while experiencing LPS-induced symptoms. The HRV BF group showed significant attenuation of the LPS-induced decline in HRV for the 6 h following LPS exposure, suggesting that HRV BF decreased autonomic dysfunction produced by LPS-induced inflammation. HRV BF also reduced symptoms of headache and eye sensitivity to light, but did not affect LPS-induced levels of pro-inflammatory cytokines or symptoms of nausea, muscle aches, or feverishness. Further evaluation of HRV BF appears to be warranted among patients with inflammatory conditions.

Influence of acute epinephrine infusion on endotoxin-induced parameters of heart rate variability: a randomized controlled trial.

OBJECTIVE: To determine whether the acute anti-inflammatory influence of epinephrine (EPI) extends to changes in heart rate variability (HRV) induced by the prototypical inflammatory stimulus, endotoxin (lipopolysaccharide [LPS]). SUMMARY BACKGROUND DATA: HRV reflects fluctuating cardiac autonomic inputs and is acutely reduced during the systemic inflammation induced by LPS as well as during severe critical illnesses such as sepsis and traumatic injury. While EPI may diminish proinflammatory cytokine release, it is unknown whether this net anti-inflammatory activity extends to HRV. METHODS: Healthy volunteers (n = 17) were randomized to either saline + LPS (2 ng/kg) or LPS + antecedent EPI infusion (30 ng/kg/min) from -3 to 6 hours relative to LPS. HRV and blood samples were obtained before EPI and LPS as well as hourly afterward. Plasma cytokines were measured by ELISA. Statistical analysis was by repeated measures analysis of variance. This study was registered at Clinicaltrials.gov and is listed under the following ID number: NCT00753402. RESULTS: LPS acutely influenced all measured parameters of HRV including standard deviation of the average beat to beat intervals over a 5-minute period, percentage of interval differences of successive interbeat intervals greater than 50 milliseconds and square root of the mean squared differences, high frequency (HF), low frequency, low frequency/HF, and very low frequency (all P < 0.01). EPI infusion reduced the inflammatory cytokine response to LPS as measured by decreased TNFalpha, IL-6, and IL-8 (P < 0.01). Relative to the saline + LPS group, antecedent EPI infusion was associated with further reductions in parameters of HRV measuring vagal/parasympathetic activity including, percentage of interval differences of successive interbeat intervals greater than 50 milliseconds, square root of the mean squared differences, and HF (P < 0.05). CONCLUSION: Prior EPI exposure exerts anti-inflammatory influences but also may reduce vagus nerve activity. Hence, acute EPI administration may be protective against early inflammatory challenges but diminish vagal nerve responsiveness to subsequent stimuli.

Low-dose steroid alters in vivo endotoxin-induced systemic inflammation but does not influence autonomic dysfunction.

Severe injury and infection are associated with autonomic dysfunction. Diminished heart rate variability (HRV) is also observed as a component of autonomic dysfunction and is induced by endotoxin administration to healthy subjects. It is established that low-dose glucocorticoid administration diminishes the systemic inflammatory manifestations of endotoxinemia but the influence of this anti-inflammatory intervention on overall autonomic dysfunction and HRV responses to endotoxin is unknown. This study was designed to assess the influence of a low-dose hydrocortisone infusion upon endotoxin-elicited systemic inflammatory responses including phenotypic features, cytokine production, and parameters of HRV. Of 19 subjects studied, nine received a continuous infusion of hydrocortisone (3 microg/kg/min continuously over 6 h) prior to intravenous administration of Escherichia coli endotoxin (2 ng/kg, CC-RE, Lot #2) while 10 healthy subjects received only the endotoxin after a 6-h period of saline control infusion. Serial determinations of vital signs, heart rate variability assessments, and cytokine levels were obtained over the subsequent 24 h. Prior cortisol infusion diminished the peak TNF-alpha (P < 0.01) and IL-6 (P < 0.0001) responses after endotoxin challenge, as compared to saline infusion controls and diminished the peak core temperature response to endotoxin (P < 0.01). In contrast to the influence of cortisol on the above parameters of systemic inflammation, the significant endotoxin-induced decreases in HRV time and frequency domains were not influenced by prior hydrocortisone treatment. Hence, alterations in autonomic dysfunction occur despite hydrocortisone attenuation of other traditional systemic manifestations of endotoxinemia. The maintenance or restoration of autonomic balance is not influenced by glucocorticoid administration.