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The perception of signals from within the body, known as interoception, is increasingly recognized as a prerequisite for physical and mental health. This study is dedicated to the development of effective technological approaches for enhancing interoceptive abilities. We provide evidence of the effectiveness and practical feasibility of a novel real‐time haptic heartbeat supplementation technology combining principles of biofeedback and sensory augmentation. In a randomized controlled study, we applied the developed naturalistic haptic feedback on a group of 30 adults, while another group of 30 adults received more traditional real‐time visual heartbeat feedback. A single session of haptic, but not visual heartbeat feedback resulted in increased interoceptive accuracy and confidence, as measured by the heart rate discrimination task, and in a shift of attention toward the body. Participants rated the developed technology as more helpful and pleasant than the visual feedback, thus indicating high user satisfaction. The study highlights the importance of matching sensory characteristics of the feedback provided to the natural bodily prototype. Our work suggests that real‐time haptic feedback might be a superior approach for strengthening the mind–body connection in interventions for physical and mental health. In the study, we evaluate the efficacy of a newly developed interoceptive training—supplementation of heartbeat sensations through real‐time haptic feedback. We revealed that the haptic feedback technology improves interoceptive accuracy, increases confidence, and shifts attention toward bodily sensations more effectively than the traditional visual feedback approach, opening new possibilities for clinical and neurowellness applications. [ABSTRACT FROM AUTHOR]

Physiological regulation strategies can be effective in reducing anxiety. However, while these strategies are often learned and practised under low‐stress conditions, they are more likely to be required under conditions of high stress. We created virtual reality (VR) biofeedback games to both teach participants a breathing technique and then practise that technique under stress. We present two studies: the first provides a proof of concept, demonstrating that participants can apply the breathing technique during stress, with a significant lowering of both respiration rate and increase in heart rate variability (HRV) under stress (p < .001). The second study explicitly evaluated the effectiveness of training by comparing trained and untrained groups. Training was associated with a significantly greater HRV (p = .008) under stress. In within‐group comparisons of HRV during stress compared to a baseline stressor presented before training, the trained group showed a significantly greater increase compared to untrained controls (p = .025). Our results show the feasibility and potential effectiveness of VR‐based games for biofeedback training under experimentally applied stress. This may offer the opportunity for clinical techniques to more closely reflect the circumstances under which those techniques will be required. [ABSTRACT FROM AUTHOR]

Vagally mediated heart rate variability (vmHRV) at resting state has been associated to cognitive functions dependent on cognitive control, such as memory. However, little is known about the phasic interaction between cognitive and autonomic control. In a pre‐registered within‐between‐subject designed experiment, the potential of vmHRV biofeedback to simultaneously stimulate vmHRV during memory processing and cognitive control over long‐term memory was tested, along with investigating psychophysiological association. 71 young healthy adults completed (twice) a false memory task in virtual reality. Immediately before memory encoding and retrieval, participants practiced either vmHRV biofeedback or a control breathing exercise. Cognitive control over long‐term memory was assessed as the confidence toward false memories and the capability to discriminate them from true memories. Resting‐state vmHRV before each test and phasic vmHRV during memory encoding and retrieval were measured as the root mean square differences (RMSSD) in the heart period. vmHRV biofeedback had neither an immediate effect on measures of cognitive control over long‐term memory nor on phasic RMSSD. Moreover, neither resting‐state nor phasic vmHRV correlated to the cognitive scores. Consequently, the utility of HRV biofeedback as a psychophysiological stimulation tool and a link between vmHRV and cognitive control over long‐term memory could not be verified. Exploratory analyses revealed that baseline shift in parasympathetic activity confounded the psychophysiological association. Future directions are provided that could shed light on the relationship between cognition and vmHRV. The results add a nuanced view on the psychophysiological relationship between autonomic and cognitive control that contradicts previous research. We provide evidence that HRV state measures assessed at baseline or during memory processing do not associate with cognitive control over long‐term memory assessed as false memory production. Moreover, short HRV biofeedback proved not to be a viable HRV stimulation method to study the heart–brain interaction. We uncovered influencing factors on the psychophysiological relationship and propose a new analysis approach important for future studies. [ABSTRACT FROM AUTHOR]

Heart rate variability biofeedback (HRVB) is an efficacious treatment for depression and anxiety. However, translation to digital mental health interventions (DMHI) requires computing and providing real‐time HRVB metrics in a personalized and user‐friendly fashion. To address these gaps, this study validates a real‐time HRVB feedback algorithm and characterizes the association of the main algorithmic summary metric—HRVB amplitude—with demographic, psychological, and health factors. We analyzed HRVB data from 5158 participants in a therapist‐supported DMHI incorporating slow‐paced breathing to treat depression or anxiety symptoms. A real‐time feedback metric of HRVB amplitude and a gold‐standard research metric of low‐frequency (LF) power were computed for each session and then averaged within‐participants over 2 weeks. We provide HRVB amplitude values, stratified by age and gender, and we characterize the multivariate associations of HRVB amplitude with demographic, psychological, and health factors. Real‐time HRVB amplitude correlated strongly (r =.93, p <.001) with the LF power around the respiratory frequency (~0.1 Hz). Age was associated with a significant decline in HRVB (β = −0.46, p <.001), which was steeper among men than women, adjusting for demographic, psychological, and health factors. Resting high‐ and low‐frequency power, body mass index, hypertension, Asian race, depression symptoms, and trauma history were significantly associated with HRVB amplitude in multivariate analyses (p's <.01). Real‐time HRVB amplitude correlates highly with a research gold‐standard spectral metric, enabling automated biofeedback delivery as a potential treatment component of DMHIs. Moreover, we identify demographic, psychological, and health factors relevant to building an equitable, accurate, and personalized biofeedback user experience. Heart rate variability biofeedback (HRVB) is an efficacious treatment for depression and anxiety, although translation to digital mental health interventions (DMHI) is hindered by the lack of normative data for real‐time HRVB metrics. This research demonstrates the utility of HRVB algorithms tailored to age and gender for DMHIs. The translation of precision care HRVB algorithms into DMHIs and other real‐world settings will improve engagement and real‐world effectiveness of biofeedback interventions for common mental health symptoms. [ABSTRACT FROM AUTHOR]

Performance and injury prevention in elite soccer players are typically investigated from physical-tactical, biomechanical, and metabolic perspectives. However, executive functions, visuospatial abilities, and psychophysiological adaptability or resilience are also fundamental for efficiency and well-being in sports. Based on previous research associating autonomic flexibility with prefrontal cortical control, we designed a novel integrated autonomic biofeedback training method called Neuroplus to improve resilience, visual attention, and injury prevention. Herein, we introduce the method and provide an evaluation of 20 elite soccer players from the Italian Soccer High Division (Serie-A): 10 players trained with Neuroplus and 10 trained with a control treatment. The assessments included psychophysiological stress profiles, a visual search task, and indexes of injury prevention, which were measured pre- and posttreatment. The analysis showed a significant enhancement of physiological adaptability, recovery following stress, visual selective attention, and injury prevention that were specific to the Neuroplus group. Enhancing the interplay between autonomic and cognitive functions through biofeedback may become a key principle for obtaining excellence and well-being in sports. To our knowledge, this is the first evidence that shows improvement in visual selective attention following intense autonomic biofeedback. [ABSTRACT FROM AUTHOR]

Heart rate variability (HRV) is associated with positive physiological and psychological effects. HRV is affected by breathing parameters, yet debate remains regarding the best breathing interventions for strengthening HRV. The objective of the current study was to test whether the inclusion of a postexhalation rest period was effective at increasing HRV, while controlling for breathing rate. A within-subject crossover design was used with 40 participants who were assigned randomly to a breathing pattern including a postexhalation rest period or a breathing pattern that omitted the postexhalation rest period. Participants completed training on each breathing pattern, practiced for 6 min, and sat quietly during a 5-min washout period between practices. Participants were given instructions for diaphragmatic breathing at a pace of six breaths/minute with or without a postexhalation rest period. Recordings of heart rate, breathing rate, HF-HRV, RMSSD, LF-HRV, and SDNN were collected before and during each of the breathing trials. HRV indices were derived from Lead 1 ECG recordings. Pairwise contrasts showed that inclusion of a postexhalation rest period significantly decreased heart rate ( p < .001) and increased HF-HRV ( p < .05). No differences were found for breathing rates ( p > .05), RMSSD ( p > .05), and SDNN ( p > .05). Results indicated that omission of the postexhalation rest period resulted in higher LF-HRV ( p < .05). A postexhalation rest period improves HF-HRV, commonly associated with self-regulatory control, yet the importance of a postexhalation rest period requires further exploration. [ABSTRACT FROM AUTHOR]

Decreased heart rate variability (HRV) is associated with posttraumatic stress disorder (PTSD) and depression symptoms, but PTSD's effects on the autonomic stress response and the potential influence of HRV biofeedback in stress relaxation training on improving PTSD symptoms are not well understood. The objective of this study was to examine the impact of a predeployment stress inoculation training (PRESTINT) protocol on physiologic measures of HRV in a large sample of the military population randomly assigned to experimental HRV biofeedback-assisted relaxation training versus a control condition. PRESTINT altered the parasympathetic regulation of cardiac activity, with experimental subjects exhibiting greater HRV, that is, less arousal, during a posttraining combat simulation designed to heighten arousal. Autonomic reactivity was also found to be related to PTSD and self-reported use of mental health services. Future PRESTINT training could be appropriate for efficiently teaching self-help skills to reduce the psychological harm following trauma exposure by increasing the capacity for parasympathetically modulated reactions to stress and providing a coping tool (i.e., relaxation method) for use following a stressful situation. [ABSTRACT FROM AUTHOR]

Paced 0.1 Hz breathing causes high-amplitude HR oscillation, triggering resonance in the cardiovascular system (CVS). This oscillation is considered to be a primary therapeutic factor in HRV biofeedback treatments. This study examined whether rhythmical skeletal muscle tension (RSMT) can also cause 0.1 Hz resonance in the CVS, and compared oscillatory reactivity in CVS functions caused by RSMT and paced breathing (PB). Sixteen young healthy participants completed five tasks: baseline, three RSMT tasks at frequencies of 0.05, 0.1, and 0.2 Hz, and a 0.1 Hz PB task. ECG, respiration, finger pulse, and skin conductance data were collected. Results showed that 0.1 Hz RSMT as well as 0.1 Hz PB triggered resonance in the CVS and caused equivalent oscillations in all measured CVS functions, although in women, RSMT compared to PB caused lower HR oscillation. Clinical application of 0.1 Hz RSMT is discussed. [ABSTRACT FROM AUTHOR]

The effects of feedback on the control of peripheral skin temperature were examined using a tension-relaxation experiment. Sixteen male undergraduates were assigned to feedback or nofeedback groups and asked to increase the temperature of the right index finger immediately after decreasing with (in the feedback group) or without (in the no-feedback group) feedback during 10 training sessions. A no-feedback transfer session (post-test) followed these sessions. During the training sessions, skin temperature corresponded to instructions in the feedback group, whereas it did not in the no-feedback group. Feedback control did not transfer to the no-feedback condition. These results were discussed in terms of the ceiling-effect hypothesis in the baseline-relaxation type experiment and of the subjects' cognitive events, including strategies. [ABSTRACT FROM AUTHOR]

Twenty-three healthy men and women participated in a 5-session experiment in which they attempted to increase and decrease their heart rate with the assistance of visual analogue biofeedback. As a group subjects did successfully raise and lower heart rate from resting baseline. These changes in heart rate were closely paralleled by changes in &Vcirc;, a measure of cardiac vagal tone. Heart rate slowing was associated with increases in &Vcirc;, and heart rate speeding was associated with decreases in &Vcirc;. Respiration rate and amplitude did not differ significantly between heart rate slowing and speeding trials, and covariance analysis indicated that respiratory changes did not account for the heart rate or &Vcirc; effects. The weighted coherence between respiration and heart rate showed that cardiopulmonary coupling increased during heart rate slowing and decreased during heart rate speeding. Individual differences in cardiac vagal tone and cardiopulmonary coupling were unrelated to heart rate speeding and slowing performance. [ABSTRACT FROM AUTHOR]

Subjects received exteroceptive feed back for bidirectional changes in slow cortical potentials or power measured from the vertex. The slow potential group succeeded in shlffin8 slow potentials toward negativity and positivity on feedback and transfer trials requiring these changes, after two sessions of training. Differentiation of negativity and positivity was accompanied by verbal reports of somatomotor activation that occurred on trials on which negative slow potentials were required (p<.01). Vertical and lateral eye movements, chin and frontalis electromyogram, and biff rate did not differentiate between negativity and positivity trials in the slow potential group. However, heart rate acceleration correlated between-subjects with slow potential segativity during feedback. Although die alpha power group did not succeed at controlling changes in alpha, evidence of a training effect appeared to verbal reports of emotional arousal (p<.05) mid focused vision (p<.08) on alpha suppressive trials in this group. We discuss the findings from the viewpoint that biofeedback tasks involving electrocortical responses are problems in the organization of action that subject8 seek to solve. [ABSTRACT FROM AUTHOR]

Forty male college student volunteers were asked either to increase their diastolic pressure or their heart rate while sitting and during orthostatic stress (going from a sifting to a standing position), and half of them were also given second- to-second visual feedback for the target variable. Systolic blood pressure was also continuously recorded. Comparisons were made between baseline and voluntary control conditions, and test trials were included to examine immediate carry-over effects. With voluntary control instructions, substantial increases in tonic levels were obtained for the three cardiovascular variables in both sitting and postural change conditions. In general, the increases were significantly greater for feedback than for no-feedback conditions. Phasic effects of feedback were also observed during postural change conditions: the blood pressure troughs and the heart rate peak occurred earlier with feedback than for instructions only. Immediate transfer effects were obtained in feedback conditions only. The results were discussed in terms of concomitant effects of somatic and cognitive activities. The distinctive feedback effects on the time course of the responses suggest that a precise analysis of response patterns is needed in selecting appropriate feedback methods in the management of orthostatic hypotension. [ABSTRACT FROM AUTHOR]

The present study was conducted to test Brener's calibration theory of visceral learning. It was hypothesized that training in discrimination of cephalic vasomotor responses would enhance acquisition of voluntary and biofeedback control of cephalic vasomotor response. Four groups were given discrimination training to detect either constriction, dilation, both constriction and dilation, or given false feedback. All groups were then given biofeedback training in constriction. All groups were assessed on discrimination accuracy, acquisition of biofeedback control of constriction, and voluntary control of dilation and constriction. The results indicated that discrimination of cephalic vasomotor responses can be learned and that this skill facilitates the acquisition of biofeedback and voluntary control of vasomotor responses. This facilitation occurs only if discrimination training is given for the specific response to be learned. The data suggest that discrimination of the relevant response is a necessary but not sufficient condition for acquisition of voluntary control in biofeedback learning. [ABSTRACT FROM AUTHOR]

Finger pulse volume (FPV) biofeedback, relaxation training (RT), and finger temperature (FT) biofeedback were compared for their effectiveness in the alteration of hand temperature (HT). It was hypothesized that the use of FPV, a more direct measure of peripheral blood flow, should be more effective in producing hand warming than the demonstrably latent FT or the less direct RT manipulation. No significant difference in HT alteration was found between the two biofeedback training groups and neither the finger temperature nor finger pulse volume biofeedback groups were more successful than the relaxation training group in the alteration of HT. No significant differences were found in the alteration of FPV among the three groups. A major finding of this study indicates that all groups produced a significant inverted U training function across trials for both FT and FP'V. In all cases, rapid learning was demonstrated in the early trials followed by a decline toward baseline in the later trials. These findings are discussed in terms of the role of strategy formation, frustration, saturation, and the limitations of the physiological learning process. [ABSTRACT FROM AUTHOR]

The effects of biofeedback and voluntary control procedures on systolic blood pressure and heart rate during postural change were investigated in 30 normotensive men. Systolic pressure was measured with a continuous blood pressure tracking cuff, and blood pressure feedback was provided on a beat-to-beat basis. Postural changes in pressure, and corresponding heart rate changes, were examined in three experimental groups (N = 10 each). In two groups, subjects were given feedback training to increase or to decrease systolic blood pressure. In the third group, subjects were simply asked to increase their pressure but were not given feedback about their performance. Voluntary control of systolic pressure was attempted while subjects were seated and during postural change-sitting to standing. Subjects were also instructed to maintain voluntary blood pressure control in subsequent no-feedback test trials. During postural change, voluntary control procedures caused significant alterations in tonic levels of systolic pressure, but phasic blood pressure reactivity was unaffected. With respect to postural changes in heart rate, both tonic and phasic treatment effects were observed. Implications of the findings for basic and clinical research are discussed. [ABSTRACT FROM AUTHOR]

The effects of verbal instructions, interbeat interval feedback, and feedback of the product of interbeat interval and pulse transit rime in enabling subjects to decrease cardiovascular activity during exercise were studied in 36 healthy volunteers cycling a modified bicycle ergometer. During the 4 training sessions subjects given product feedback showed smaller decreases in interbeat interval and pulse transit time during exercise than did subjects receiving only verbal instructions. Subjects receiving interbeat interval feedback fell between the other two conditions. On the fifth session, during which feedback was not provided, no differences were found among the three conditions. The use of feedback of the product of interbeat interval and pulse transit time to control the sympathetic input to the heart and in the treatment of angina pectoris is discussed. [ABSTRACT FROM AUTHOR]

The current study was concerned with the discrimination of 12-15 Hz (15μV) surface cortical EEG, recorded over the dominant hemisphere. This EEG bandwidth is sometimes called the SMR (sensorimotor rhythm), and has been associated with seizure reduction. Thirty-six normal subjects were divided into three groups and exposed to three methods of discrimination training: response feedback, production feedback, and no-feedback control. In the initial assessment session, all subjects were asked to detect the presence of SMR by pressing a response button in the absence of feedback. Over the next 4 training sessions, the control group continued without feedback, while the response feedback group received feedback (tone) for correct discriminations, and the production group received feedback for producing the SMR signal. Discrimination performance was assessed during a 15-min no-feedback test period, following each feedback segment. The final session took place two weeks after training had been completed and was the same as session 1. The results showed that both experimental groups improved discrimination accuracy over baseline, and relative to the control group. Performance of the groups at baseline was not significantly different, ranging between 16% and 29% correct. Peak performance during training showed that both experimental groups improved over baseline and relative to the control group, averaging 17%, 43% and 78% correct for the control, response and production feedback groups, respectively. In the final assessment, all groups deteriorated in performance, but the production group remained significantly above baseline levels. No changes in average SMR time or frontal EMG were noted. However, time spent in the occipital alpha bandwidth 8-13 Hz (25 μV) did increase in the best discriminators. This may indicate some discrimination of subjective sensations associated with SMR discrimination training. [ABSTRACT FROM AUTHOR]

This study evaluated the effectiveness of laryngeal muscle biofeedback, a common treatment for subvocalization, utilizing a strict control group structure. Subjects were 29 undergraduates assigned to Laryngeal Feedback (N = 10), Masseter Feedback (N = 10), or No Feedback Control (N = 9) condition. The results indicated that laryngeal muscle biofeedback had no specific treatment effect; however, masseter biofeedback demonstrared a specific treatment effect when the new procedure was utilized. Subjectes in the Masseter Feedback Group displayed masseter EMG levels which were substantially lower than subjects in the Laryngeal Feedback Group (p<.05). In order to validate the results of the biofeedback control procedure, accuracy of myogenic perception was also tested, and found to be significant for the masseter (p<.001) but not for the laryngeal muscle. It is shown that the biofeedback control procedure can more accurately assess the presence or absence of specific treatment effects in biofeedback. Theoretical implications of the myogenic perception concept are discussed, and suggestions for future research in biofeedback and myogenic perception are provided. [ABSTRACT FROM AUTHOR]

Two experiments were conducted in the present investigation. In the first, subjects receiving finger temperature feedback showed significant increases in digital temperature during the first 12 min of the first training session, an effect not shown by subjects receiving autogenic training, electromyograph feedback, or simple instructions to increase finger temperature. During five subsequent training sessions, significant temperature elevations were not shown by any group. During a post training test of voluntary control, only the temperature feedback group produced a significant elevation in digital temperature. In a second voluntary control test, conducted outside the laboratory, no temperature increases were found. It was hypothesized that finger temperature elevations produced during temperature feedback might be time limited or that excessive session length might impede training. Accordingly, a second experiment was performed in which training periods and session length were reduced. Temperature feedback subjects now consistently increased theft finger temperature during training and without feedback, both inside and outside the laboratory. These effects were not shown by control subjects. It is concluded that consistent finger temperature elevations during training are necessary for generalization of this response outside the laboratory. Although relaxation was not necessary for temperature elevation in the laboratory, it might have enhanced this effect outside the laboratory setting. [ABSTRACT FROM AUTHOR]

A temperature-compensated and a simpler, non-compensated respiration measuring belt based on an infrared light sensing principle are described. The systems are designed to overcome shortcomings in usual respiration monitoring methods applicable to: 1) a respiratory-sinus-arrhythmia quantification study, and 2) a portable circulation monitoring system. Both devices have a rugged and lightweight construction, are comfortable for subjects, relatively free from artifacts, are of low cost, and are simply interfaced to recording apparatus. Additionally, the temperature-compensated version allows for DC-recording, permitting monitoring of breath-holding, which is not feasible with conventional transducers. The simple construction of the non-compensated version makes it especially suitable to routine therapy and monitoring applications. Use of two temperature-compensated belts measuring thoracic and abdominal circumference allows for breathvolume calibration by multiple linear regression with reliabilities between 75 and 95 %. The mathematical basis for this calibration procedure is discussed in detail. [ABSTRACT FROM AUTHOR]

Because of its ventricular origin, T-wave amplitude (TWA) has been suggested as a plausible candidate index for assessing myocardial sympathetic activity. This idea received some support in the literature but recent (1979-1980) papers from three independent laboratories have criticized the validity of TWA, and have at least implicitly suggested that TWA should he abandoned as a noninvasive sympathetic index. This paper examines these criticisms and finds them to he of questionable validity and certainly not of sufficient strength to support abandoning TWA. Instead, the conclusion drawn here is that we should continue to critically assess both TWA and other noninvasive candidate sympathetic indices by using invasive myocardial indices as criterion measures and both behavioral and pharmacological interventions as manipulations. [ABSTRACT FROM AUTHOR]

Three groups of 10 normal subjects were trained with 13 maximal isometric contractions on each of 8 days. During 8 of the 13 trials, subject groups received either myoelectric feedback (N4FB), or force feedback (FFB), or no feedback. Over the 8 training days all groups increased EMG activity, but no significant group differences in rate of acquisition were obtained. All groups made gains in force over the 8 days. Force feedback produced better acquisition than either MFB or control conditions. However, both MFB and FFB produced comparable and significant differences between feedback and no-feedback trials within a session, highlighting the importance of control group designs in the assessment of biofeedback effects. Dissociation between surface EMG and force was shown not only in the training effects, but also in the difference between feedback and no-feedback performance within a session. An analysis of covariance revealed that during feedback trials MFB produced some EMG facilitation which could not be attributed to increased force production. This effect may have been due to selective reinforcement by MFB of co-contraction in the extraneous musculature, or of changes in motor unit firing patterns. These phenomena may also account for the relative failure of MFB to facilitate force acquisition. A one-month follow-up showed significant retention following similar losses of force in all groups. [ABSTRACT FROM AUTHOR]

A low-noise preamplifier for electromyographic applications Is presented. The design features modifiable gain and bandpass characteristics, driven input shielding for high common-mode rejection, and integral optical isolation for participant safety. [ABSTRACT FROM AUTHOR]

Three monkeys were trained to slow and to speed heart rate on an operant schedule. After the animals were performing highly reliably they received injections of nitroglycerin or phenylephrine to elicit baro reflexes during control periods and during slowing or speeding sessions. The finding were that each animal reliably attenuated its baroreflex sensitivity and thereby avoided shock. Thus, the data showed that under appropriate behavioral conditions homeostatic adjustments of the cardiovascular system are reduced. [ABSTRACT FROM AUTHOR]

Video color-graphics hardware and especially moderate resolution color CRT displays, are rapidly becoming one of the most popular peripherals in the computer industry. This paper describes the utilization of a color-graphic display terminal as the main feedback component in a hybrid laboratory-built microcomputer system for implementing skin temperature biofeedback and monitoring procedures. [ABSTRACT FROM AUTHOR]

This study addressed the relative contributions of self-regulated heart rate change and belief that heart rate is changing in an instructed direction to the perception of cold pressor pain. Forty male volunteers were each assigned to one of four combinations of increase or decrease heart rate instructions and increase or decrease feedback conditions. Subjects were given an initial 45-sec cold pressor test, 25 feedback trials, and a final cold pressor in which they were told to change their heart rate in the instructed direction, but without the aid of feedback. Subjects were instructed specifically that increased heart rate was associated with increased pain and decreased heart rate with decreased pain. The veridical groups (consistent instructions and feedback) showed appropriate heart rate changes during biofeedback training and parallel changes in heart rate and pain perception during the final cold pressor. The non-veridical (reverse) feedback groups showed no heart rate change during biofeedback training and no relationship between heart rate and pain perception changes during the final cold pressor test. EMG, respiration, and skin conductance data are presented, and several mechanisms are proposed to explain the physiological and subjective changes. [ABSTRACT FROM AUTHOR]

Forty-eight normotensive subjects underwent one of low training conditions: Transit time plus stress (TTPS), Transit time minus stress (TTMS), False feedback plus stress (FF), and a stress only Control (C). In the first session, all subjects received an arithmetic stressor bid without training. In the second and third sessions, subjects received training appropriate to their conditions. The TTPS and FF groups received arithmetic stressors prior to the transit time training, whereas the TTMS group rested prior to training. Training in the TTPS and TTMS groups consisted of heat-to-beat pulse transit time feedback. During the training period the FF group received bogus feedback. In the fourth session, all subjects received the stress- or followed by instructions to lower blood pressure (increase transit time). No feedback was available. Significant transit time decreases occurred in response to the stress in all groups during the first session. However, in the fourth session, the TTPS group showed virtually no transit time decrease during the stress- or, while the remaining three groups continued to show significant transit time decreases to the stressor. It was concluded that sell control over the subjects' reactivity to the arithmetic stressor had occurred in the transit time plus stress group. This effect did not appear to be due solely to either repeated exposure to the stressor or to leaned control via feedback training. Rather, the effect seemed to result from the combination of exposure and training. [ABSTRACT FROM AUTHOR]

Nonspecific factors such as placebo or expectancy effects may materially influence therapeutic outcome in EMG relaxation training. Yet, controlling for the expectations of experimenters has received little attention even though Rosenthal's Experimenter Expectancy Effect is well-documented. This study examined the effects of experimenter expectancy on frontal EMG conditioning. During training, experimenters were given either no expectancy or led to believe that EMG conditioning would be either difficult (low expectancy) or easy (high expectancy) to achieve. Then, the three groups of experimenters collected data from subjects undergoing 20 min of either contingent or noncontingent reinforcement for frontal EMG decreases. Postexperimental credibility checks indicated that experimenters were unaware they were being studied but could identify their expectancy condition when informed of the three conditions. Differential EMG behavior was observed between groups conditioned by experimenters with no expectancies, with contingent subjects achieving significantly lower EMO levels than noncontingent subjects. Differences were not exhibited, however, between contingent and noncontingent subjects trained by experimenters with either low or high expectancies. These findings suggest that experimenters with prior expectations may covertly communicate to subjects response sets that interfere with acquisition of differential EMG behavior. [ABSTRACT FROM AUTHOR]

The current study examined the effects of pulse transit time feedback on systolic and diastolic blood pressure. Three subjects were given feedback designed to increase or decrease transit times. Eleven-twelve one hour training sessions were provided over a two-week period. The results showed that during increase training, significant increases in systolic pressure and heart rate were observed, while pulse transit time showed a significant decrease. Diastolic blood pressure increases were moderate and only inconsistently observed. During decrease training, diastolic pressure and heart rate declined significantly below baseline. Pulse transit time increases were consistent but lower in magnitude than observed for the opposite training condition. Moderate systolic blood pressure decreases were inconsistently observed. [ABSTRACT FROM AUTHOR]

Brener has proposed a general theory of the development of voluntary control which offers as its focus an account of the process underlying the acquisition of control over autonomic responses. This account views the acquisition process as consequent to the development of the subject's ability to discriminate afferentation related to the response state to be produced and to his formulating an appropriate response image on the basis of this afferentation. The paper begins with an extensive review of biofeedback studies pertinent to the theory. This review yields little convincing evidence for Brener's views. Selected studies on the performance and the acquisition of motor skills and on the nature of the image are then examined. These suggest that the development of control of a response may rely primarily on efferent processes, with afferent processes playing, at most, a secondary role. A two-process theory of the acquisition of autonomic control is then presented. The theory proposes that, in most instances, biofeedback training leads to autonomic control through a process consisting primarily in the identification of efferent behavioural programmes already within the subject's repertoire. The theory further proposes that an afferent acquisition process such as postulated by Brener may also underlie the development of autonomic control, but only under conditions where behavioural programmes effective in controlling the target response are either unavailable or inaccessible to the subject. [ABSTRACT FROM AUTHOR]

Thirty-two subjects participated in 6 biofeedback training sessions to produce increases and decreases in skin conductance (SC) or heart rate (HR). Performance on control trials was examined with respect to SC and HR, as well as respiratory and somatomotor variables. The subjects also participated in 3 test sessions (on days 2, 5, and 9), which evaluated their ability to discriminate the target autonomic response, and sought to identify the bases for SC and HR discriminations. This design permitted examination of three major predictions from Brener's theory about the process which underlies the acquisition of autonomic control through biofeedback. The first prediction, that positive correlations should be obtained between control and discrimination performance throughout training, was not supported by the data. The other predictions, that control and discrimination performance both should become more specific to the target response as a function of training, were likewise not supported. On the whole, neither for SC nor for HR control was the pattern of results favorable to Brener's views. [ABSTRACT FROM AUTHOR]

In light of the continuing popularity of frontalis EMG feedback for general relaxation purposes, a pertinent question is whether this procedure is superior to feedback from other muscles. This question was addressed by comparing a frontalis feedback group (n = 12) with a forearm feedback group (n = 10) in a one-session experiment. The experimental session included a 10-min rest period preceded by verbal relaxation instructions and demonstration of the respective feedback contingencies, and followed by a 30-min feedback period. EMG records were obtained from forehead, forearm, neck, masseter, sternomastoid, and lower leg. In the two target muscles, significant group differences developed during rest, but no additional significant effects were produced during feedback. Regarding the four untrained sites, EMG tended to decrease in the forehead group, but not significantly below the levels of the forearm group. Simultaneous EMG cross-correlations within 5-min intervals based on successive 1-sec averages showed significant covariation between muscles in the head and neck area; the source of this covariation was uncertain, however -- electrical "cross-talk" and generalized muscular responding were two possibilities discussed. [ABSTRACT FROM AUTHOR]

Johnston (1977) has argued that studies of the serf-control of heart rate have not provided clear support for the theory that biofeedback aided learning is analogous to a motor skill. This could be because the tasks studied are not modelled closely enough on the skills analogized and because feedback might aid control rather than learning. These possibilities were examined in a series of five studies on decreasing interbeat interval (i.e. increasing heart rate) by a specific amount. It was shown in two studies that analogue feedback was superior to binary. The effect of frequency of feedback was weaker but frequent feedback was better than infrequent in two out of three studies. Feedback plus verbal instructions was better than verbal instructions alone and performance deteriorated when feedback was withdrawn. The results support the view that heart rate control does resemble a motor skill when the task set the subject has close similarity to a conventional skilled task and that, under these circumstances, feedback primarily aids performance and not learning. [ABSTRACT FROM AUTHOR]

Three experiments (total N = 102) are reported which examined the relationship between individual differences in ability to control heart rate (HR) with feedback and differences in self-reported cognitive strategies, personality variables (locus of control, state and trait anxiety), physiological variables (respiration, somatic activity, basal HR and HR variability, and initial ability to control HR without feedback), and several auxiliary variables (e.g., weight, smoking, gender, exercise, anal meditation). Two sets of analyses were performed. In the first set, differences in cognitive strategies and physiological concomitants between HR decrease and HR increase were studied revealing disparate patterns of cognitive strategies and physiological concomitants for the two directions of HR control. In the second set, the group of cognitive, strategy, personality, physiological, and auxiliary variables was searched to determine it any variables were related to individual differences in ability to decrease or increase HR. Cognitive strategies, personality, and auxiliary variables were generally unrelated to ability to control HR in either direction. Use of two cognitive strategies was found to be associated with lack of ability to increase HR, and non-smokers were better able to decrease HR. Strong relationships were found for somatic activity and ability to control HR without feedback, both of which successfully predicted differences in ability to decrease and increase HR with feedback. Implications of these findings for past and future studies of voluntary control of HR are discussed. [ABSTRACT FROM AUTHOR]

Tension levels from muscles in the forehead (frontalis) and back of the neck (semispinalis capitis) were simultaneously recorded during short term relaxation training with EMO feedback to assess the efficacy of this technique for producing generalized deep muscle relaxation. The degree of association between the activity of the two muscles was measured both with cross-correlation coefficients and a linear regression technique. The two muscles showed a tendency to covary which did not change during training and was unrelated to which muscle was the source of feedback. These results provide evidence for a moderate degree of association between these muscle groups during relaxation training and suggest that EMO feedback may be more useful in producing general relaxation than was previously thought. [ABSTRACT FROM AUTHOR]

Thirty-six male students were instructed to raise or lower their heart rates (HRs) and were provided with one of three different schedules of HR biofeedback. Within each direction of control condition, subjects were exposed to continuous beat-by-beat visual feedback, no feedback, or feedback presented according to a variable ratio (VR) schedule. During 4 training sessions VR subjects received feedback of a randomly selected 100%, 75%, 50%, or 25% of their heartbeats. All groups significantly altered their HRs in the instructed direction. For HR speeding, VR feedback produced significantly faster HRs than did continuous feedback while the VR schedule was in effect. No significant differences in HR slowing performance occurred among the three slowing groups. Resting initial HR levels did not significantly affect either speeding or slowing performance. [ABSTRACT FROM AUTHOR]

Fourteen female subjects suffering from idiopathic Raynaud's Disease were trained during 6 laboratory sessions to raise skin temperature. All subjects were given autogenic instructions and half the subjects were given skin temperature feedback from the middle digit of the dominant hand. Autogenic instructions were found to produce small but reliable increases in skin temperature regardless of whether or not feedback was provided. Following the autogenic instructions all subjects showed decreases in skin temperature. However, these decreases were greater for subjects not receiving feedback than for those receiving feedback. Theoretical implications of these data are discussed. [ABSTRACT FROM AUTHOR]

Four normal male subjects were exposed to 5 30-mm alternate-day sessions of continuous frontalis EMG biofeedback training preceded by 15-mm adaptation periods. A computer- controlled scanning electromyograph sampled integrated EMG activity from the frontalis and seven adjunctive muscle groups. Tensional profiles for all eight muscle groups were assembled every 1.84 sec, resulting in an 8 × 960 data array for each session. Statistical analyses revealed that although frontalis EMG levels decreased significantly in the training, those of adjunctive recording sites did not. Cross correlation analyses for session 1 frontalis and adjunctive site EMG levels showed typically negligible correlations at all temporal lags, although some neck sites showed moderate cross correlation with the frontalis in 2 subjects. Separate principal-component analyses for sessions 1 and 5 produced little evidence for a general muscle tension factor. Low coefficients of congruence between session 1 and session 5 truncated-component solutions demonstrated little replicability of tensional linkages from the first to the last session. [ABSTRACT FROM AUTHOR]

A circuit is described which provides feedback from one of many varying physiological parameters by comparing the instantaneous present value to an integrated version of the same parameter. A success or failure signal is generated when the instantaneous value falls below or exceeds the integrated level. Furthermore, the integrated level is continually updated, so that eventually (depending on the selected time constant) the integrated level will equal the instantaneous level if it remains stable; thus a trainee cannot succeed or fail for a long period of time. A design for a continuous analog display of the values on an oscilloscope is also described. [ABSTRACT FROM AUTHOR]

In EMG biofeedback it has been suggested that covariation in tension levels between a trained and untrained muscle increases with continued training of the target muscle. Predictions of this sort are in contrast to the notion of response generalization which would predict decreased covariation between trained and untrained muscles with continued training. This study examined covariation between facial and forearm EMG levels during facial EMG biofeedback, and evaluated changes in such covariation which occurred with continued facial EMG training. Two groups of individuals were trained either to increase or to decrease facial muscle tension in 3 laboratory sessions during which simultaneous measures of facial and forearm EMG were obtained at 1-min intervals. Comparison of facial EMG measures for these groups with those for a third, noncontingent control group revealed bidirectional conditioned effects for each training session. Some covariation between forearm and facial EMG was apparent for all groups. However, examination of change in covariation across sessions revealed that covariation decreased for groups receiving facial muscle training, whereas covariation levels exhibited by the noncontingent feedback group remained stable. This finding was consistent with the concept of response generalization but not with the notion of muscle tension generalization as employed in EMG biofeedback. [ABSTRACT FROM AUTHOR]

In three fractorial experiments, auditory vs visual vs tactile feedback, analog feedback vs analog feedback which was anchored, and sex, were varied to assess the effects of these variables on performance in short-term biofeedback training of heart rate reduction, hand temperature increase, and forehead muscle tension reduction. A total of 108 subjects served In the study. Moderate but reliable changes were found during the course of the training session for all three physiological responses. The ability to reduce heart rate in a single training session did not appear to be a function of any of the variables manipulated in this study, but rather could be attributed to adaptation. In both muscle tension and temperature training, however, there were significant interactions between sex and sensory modality of the feedback stimulus and, in the case of muscle tension training, between Information content of the feedback signal and sex. The overall pattern of results indicated that performance during biofeedback training is a complicated function of sex and the type of signal used to provide feedback, and that this function is not constant across physiological response systems. [ABSTRACT FROM AUTHOR]

An experiment addressing several unresolved issues in operant conditioning of heart rate (HR) in human subjects was performed. Cardiac-respiratory relationships, cardiac-somatic relationships, effects of biofeedback, and individual differences were examined in terms of their stability across multiple training sessions. Thirty subjects participated in 3 training sessions. Each session began with 4 trials of attempted HR change without feedback followed by 8 trials with "proportional" feedback of HR. On half the trials HR decrease was attempted while HR increase was attempted on the other half. Subjects were instructed to keep their respiration rate (RR) constant and not to engage in undue movement or muscle activity. Results indicated that subjects were able to produce significant HR increases and decreases from baseline levels, but these changes were accompanied by parallel changes in respiratory and somatic variables which persisted across sessions. Analysis of data from individual subjects was performed to explore the nature of individual differences in cardiac-respiratory-somatic patterns. The effects of biofeedback were unimpressive, suggesting at best a minor improvement in cardiac control with increased respiratory concomitance. Cardiac control, feedback effects, and cardiac-somatic patterns were stable over sessions. There was evidence of some reduction in cardiac-respiratory parallelism across sessions. [ABSTRACT FROM AUTHOR]

To test the hypothesis that voluntary heart rate (HR) control is possible with simultaneous muscular effort, S male subjects were trained in feedback assisted bidirectional HR control, and also practiced hand grip exercises requiring different levels of effort for 3 consecutive daily sessions. In a fourth session subjects were required to increase and decrease HR while simultaneously performing muscle contractions of 0%, 10%, 30% and 50% of maximum voluntary contractions. Substantial and reliable variations in HR were produced by instructions and by muscular effort during the first 3 sessions; and in the fourth session bidirectional HR control continued even with the relatively elevated baselines induced by muscular effort. Concomitant chin EMG levels did not vary with degree of muscular effort nor with instructions to increase or decrease HR, but increased over the course of any type of trial. Discussion suggests the use of artificially elevated baselines as a strategy for studying HR deceleration and concludes that the present study provides strong evidence of subjects' abilities to voluntarily control HR during muscular effort. This conclusion lends support to the notion that biofeedback therapies may be of clinical utility in real life by modulating the eliciting effects of stressors. [ABSTRACT FROM AUTHOR]

This article discusses the technique of microneurography and its limitations. Stimuli capable of changing sympathetic neural discharge, recorded from peripheral nerves in conscious subjects, are noted. The notion that both internal and external stimuli can alter sympathetic activity should encourage psychophysiologists to examine these factors as possible elements used by subjects to process signals representing a component of autonomic behavior. [ABSTRACT FROM AUTHOR]

The effects of heart rate feedback delay upon bidirectional heart rate control were determined by comparing four groups of 10 subjects who received either: a) immediate feedback, or b) feedback that was delayed by 1.4 sec, 5 sec, or 14 sec. All subjects received 3 sessions of training which included 3 within-session phases, i.e. 2 (pre and post-feedback) Instructional Control phases during which subjects were instructed to speed or slow heart rate without the aid of feedback, and a Feedback phase during which bidirectional heart rate control was assisted by analogue heart rate feedback. Heart rate, chin EMG, and respiration rate were recorded during all phases. The results indicated that the magnitude of heart rate increases and decreases was systematically influenced by differing amounts of feedback delay. For increasing and decreasing heart rate, the group receiving immediate feedback showed superior heart rate control in comparison to groups which received feedback that was delayed by 14 sec. The strongest effects of feedback delay were evident during Feedback and the final Instructional Control phase. Only the group receiving immediate feedback improved HR control during Feedback and post-feedback Instructional Control phases. These findings were discussed in terms of a motor skills learning model for learned HR control. It was concluded that while many of the same parameters influence HR and motoric behavior, the two responses should not be regarded as equivalent. [ABSTRACT FROM AUTHOR]

Fifty-six adult males who were hospitalized with anxiety related problems were randomly assigned to the conditions formed by a 2 (instructions to increase heart rate, instructions to decrease heart rate) × 3 (true biofeedback, placebo biofeedback, no biofeedback) factorial plus 1 (no-treatment control) design. Subjects were seen for 4 heart rate training/recording sessions and 1 subsequent transfer-test session. Results indicated that: a) neither instructions alone nor the combinations of instructions and true or placebo biofeedback were more effective than simply sitting quietly (adaptation) for decreasing heart rate, b) instructions plus true biofeedback was more effective than instructions alone or instructions plus placebo biofeedback for increasing heart rate, c) multiple sessions of training did not enhance the level of control achieved early in the first session, d) the control achieved with biofeedback did not transfer to a subsequent no-biofeedback situation, and e) biofeedback training did not influence subjects' subjective anxiety levels. [ABSTRACT FROM AUTHOR]

Conventional operant biofeedback methods have not generally been successful in producing large-magnitude cardiac decelerations, whereas a Pavlovian approach using negative body tilt as an unconventional unconditional stimulus (US) has been reported to yield more promising results. The two experiments reported here employed this powerful (elicits decelerations of 35 bpm) new US in an "imaginationar" form of Pavlovian conditioning wherein the conditional stimulus (CS), rather than being a conventional and simple one (e.g., tone or light), was the following complex event: the word "drop" to which the subject was instructed to drop his head back, imagine the US, and, to help this imaginational process, to roll his eyes back. In Exp. I this complex CS was temporarily paired with the US at a .5-sec CS-US interval for 12 Experimentals, whereas for 12 Controls the same complex CS followed the US by 17 sec in a long backwardcontrol arrangement. The CS in the Experimentals yielded some 10 bpm decelerative responses relative to the 4-bpm levels of the Controls, and during extinction (US omitted) the Experimentals' decelerations returned to the 4-bpm level of the Controls. Exp. II assessed the possible contribution of the various motoric aspects of the complex "drop" CS by presenting 10 subjects with the same "drop" CSs, but omitting both the associated tilt USs and instructions to imagine the flit. With these omitted, the "drop" CS produced no significant decelerations. Finally, a significant Experimentai-Control difference in Exp. I indicated that the deceleration training shows generalization or transfer to a situation where the subject is sitting up in a normal position rather than lying on the tilt table. [ABSTRACT FROM AUTHOR]

Three biofeedback procedures were compared for their effectiveness in training subjects to modify systolic blood pressure (BP). Three groups of 6 normotensives received three training sessions using one of three types of systolic BP feedback: 1) proportional feedback at 75-sec intervals, 2) relatively continuous proportional feedback, or 3) a form of continuous binary feedback. Three subjects also completed a fourth, no-feedback, session. Each session consisted of 5 training cycles, during which the subject was first instructed to "lower" BP and then "don't lower" BP. This design permitted demonstration of subjects' ability to control BP, rather than just lowering it. Systolic and diastolic Bps were recorded, as were heart rate, respiration rate and respiration volume. The continuous binary feedback technique was most successful in producing systolic BP control, apparently due to the short feedback latency and maximal information available to subjects. Diastolic BP often increased within sessions even when systolic BP decreased. No consistent covariation between BP and other physiological responses was observed, although at times these responses varied systematically with instruction. Continued systolic BP control at diminished levels was demonstrated by subjects who completed a fourth, no-feedback, session. [ABSTRACT FROM AUTHOR]

In order to determine the effects of long-term alpha-enhancement training on EEG alpha amplitudes and on experiential states, a 2 × 2 factorial design was employed with two levels of Sensory Deprivation (high and low) and two of Feedback-Electrode Placement (O2-F4 and O2-ear). Twelve research participants (3 per cell) engaged in 10 52-mm sessions of eyes-closed alpha-enhancement training with proportional auditory feedback of integrated alpha amplitudes. The results led to five major conclusions: 1) even long-term alpha-enhancement training (with proportional feedback of alpha strength) does not result in the learned enhancement of alpha strength significantly above optimal eyes-closed baseline levels; 2) in some cases, alpha-enhancement training does result in the maintenance of optimal alpha levels; 3) sub-baseline increases in alpha production during alpha training are most often the result of the gradual dissipation or neutralization of alpha-inhibitory influences (disinhibition or habituation versus enhancement); 4) the occurrences of unusual experiences during alpha training are partly due to the sensory deprivation conditions of the experimental procedures, and partly due to the effects of suggestion and the experience of success; and 5) alpha feedback from the O2-F4 and O2-ear placements do not have differential effects on EEG alpha or on experiential state. [ABSTRACT FROM AUTHOR]