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PubMed1990

A systematic comparison of feedback and staff discussion in changing the ward atmosphere.

The efficacy of therapeutic programmes depends on several characteristics of the treatment environment. For this reason therapists are increasingly directing their efforts towards changing the social characteristics of treatment units. This study aimed to promote change in social climate by providing nursing staff with structured information about their unit. The 'real' and 'ideal' social climate of the unit was defined and assessed using the Ward Atmosphere Scale. All staff were asked to complete it during an assessment period. Feedback about their perception of the unit was provided to staff in two ways. One group of staff received written feedback only; a second group received in addition the opportunity to discuss the feedback and strategies for reducing the real-ideal discrepancies in four once-monthly meetings. The effect of the feedback on the social climate of the unit was ascertained by further assessment using the WAS and from interviews with all staff. The evaluation suggested that the feedback had contributed to changes in several procedures in the unit and to a reduction in the real-ideal discrepancies for the systems maintenance elements. The effect was greater for the group of staff who had the opportunity to discuss the feedback in a formal setting.

Communication↗
PubMed1983

The comparative efficacy of relaxation training and masseter EMG feedback in the treatment of TMJ dysfunction.

The present series of single case studies was designed to evaluate the comparative efficacy of masseter EMG feedback with progressive relaxation training in the treatment of TMJ dysfunction. Study 1 employed a multiple baseline design across the symptoms of jaw pain, jaw tension and shoulder pain in a patient with chronic TMJ problems. The results indicated that relaxation training was the treatment responsible for improvements in subjective ratings of jaw pain and tension, whereas masseter EMG feedback provided little additional benefit. Trapezius EMG feedback was necessary to provide improvements in ratings of shoulder pain. Study 2 consisted of four single case designs in which masseter EMG feedback and relaxation training were compared with four TMJ patients. Results indicated that relaxation produced clear improvements in pain and tension ratings for two patients, a combination of EMG feedback and relaxation training resulted in slight improvements in one patient, and neither treatment procedure was effective for the final patient. The possibility of wide-scale application of relaxation training with TMJ patients and the need for further controlled research of masseter EMG feedback were discussed.

Adult↗
PubMed2006

Development and application of a real-time monitoring and feedback system for deep inspiration breath hold based on external marker tracking.

Respiration can cause tumor movements in thoracic regions of up to 3 cm. To minimize motion effects several approaches, such as gating and deep inspiration breath hold (DIBH), are still under development. The goal of our study was to develop and evaluate a noninvasive system for gated DIBH (GDIBH) based on external markers. DIBH monitoring was based on an infrared tracking system and an in-house-developed software. The in-house software provided the breathing curve in real time and was used as on-line information for a prototype of a feedback device. Reproducibility and stability of the breath holds were evaluated without and with feedback. Thirty-five patients undergoing stereotactic body radiotherapy (SBRT) performed DIBH maneuvers after each treatment. For 16 patients dynamic imaging sequences on a multislice CT were used to determine the correlation between tumor and external markers. The relative reproducibility of DIBH maneuvers was improved with the feedback device (74.5% +/- 17.1% without versus 93.0% +/- 4.4% with feedback). The correlation between tumor and marker was good (Pearson correlation coefficient 0.83 +/- 0.17). The regression slopes showed great intersubject variability but on average the internal margin in a DIBH treatment situation could be theoretically reduced by 3 mm with the feedback device. DIBH monitoring could be realized in a noninvasive manner through external marker tracking. We conclude that reduction of internal margins can be achieved with a feedback system but should be performed with great care due to the individual behavior of target motion.

Artifacts↗
PubMed2001

Modifying modal characteristics of sound fields by state feedback control.

State feedback control of a sound field is investigated for improving the irregular distribution of the natural frequencies at low frequencies. A state-space description of a sound field is derived from an inhomogeneous wave equation using the finite element method. The feedback control system is realized as a feedback filter between sensor microphones and control sources using a state estimator for a linear dynamic system. Pole allocation is employed for calculating the state feedback gain vector, such that the roots of the closed-loop system have the desired modal distribution. Computer simulations are performed to demonstrate the control achieved by distributing the lowest undamped natural frequencies in a uniform manner. As a result, the transfer functions with the state feedback control are modified so as to have peaks at identical intervals for the frequency range of interest. A control experiment in an enclosure is carried out with the same objective of control as modeled in the simulations. The experiment verifies that the desired modal distribution can be achieved by introducing the proposed state feedback control into a sound field.

Journal Article↗
PubMed2003

Changes in Escherichia coli rRNA promoter activity correlate with changes in initiating nucleoside triphosphate and guanosine 5' diphosphate 3'-diphosphate concentrations after induction of feedback control of ribosome synthesis.

rRNA synthesis is the rate-limiting step in ribosome synthesis in Escherichia coli. Its regulation has been described in terms of a negative-feedback control loop in which rRNA promoter activity responds to the amount of translation. The feedback nature of this control system was demonstrated previously by artificially changing ribosome synthesis rates and observing responses of rRNA promoters. However, it has not been demonstrated previously that the initiating nucleoside triphosphate (iNTP) and guanosine 5'-diphosphate 3'-diphosphate (ppGpp), the molecular effectors responsible for controlling rRNA promoters in response to changes in the nutritional environment, are responsible for altering rRNA promoter activities under these feedback conditions. Here, we show that most feedback situations result in changes in the concentrations of both the iNTP and ppGpp and that the directions of these changes are consistent with a role for these two small-molecule regulators in feedback control of rRNA synthesis. In contrast, we observed no change in the level of DNA supercoiling under the feedback conditions examined.

Adenosine Triphosphate↗
PubMed1978

Characteristics of inspiratory inhibition by phasic volume feedback in cats.

The dependence of phrenic efferent discharge on vagal-volume feedback was examined in barbiturate-anesthetized, paralyzed cats ventilated by a phrenic-driven servo respirator. The characteristics of the respiratory were altered for a single breath, and the resulting change in phrenic activity was quantitated by comparison with phrenic activity without phasic volume feedback. The relation between volume feedback and phrenic inhibition was determined both when inspiratory termination occurred during the rising phase of phrenic discharge and during the plateau observed with barbiturate-induced apneusis. Inhibition of inspiratory activity occurred only when lung volume exceeded a time-dependent threshold. Above this threshold, andextending over a substantial volume range, volume feedback caused graded and reversible inhibition of phrenic discharge. The threshold for graded inhibition declined progressively during the inspiratory phase, showing no obvious relation to the level of inspiratory activity. At any particular time, the relation between volume and phrenic inhibition was convex to the volume axis, and the slope of the relationship increased with inspiratory time. The results indicate that a) volume feedback inhibits inspiration in a graded manner, b) partial inhibition of phrenic activity renders it more susceptible to additional inhibition, and c) inhibitory effectiveness of volume feedback increases with time.

Animals↗
PubMed2006

Treating disturbances in the relationship between mothers with bulimic eating disorders and their infants: a randomized, controlled trial of video feedback.

OBJECTIVE: Maternal eating disorders interfere with parenting, adversely affecting mother-infant interaction and infant outcome. This trial tested whether video-feedback treatment specifically targeting mother-child interaction would be superior to counseling in improving mother-child interaction, especially mealtime conflict, and infant weight and autonomy. METHOD: The participants were 80 mothers with bulimia nervosa or similar eating disorder who were attending routine baby clinics and whose infants were 4-6 months old. They were randomly assigned to video-feedback interactional treatment or supportive counseling. Both groups also received guided cognitive behavior self-help for their eating disorder. Each group received 13 sessions. The primary outcome measure was mealtime conflict; secondary outcome measures were infant weight, aspects of mother-infant interaction, and infant autonomy. RESULTS: Seventy-seven mothers were followed up when their infants were 13 months old. The video-feedback group exhibited significantly less mealtime conflict than the control subjects. Nine of 38 (23.7%) in the video-feedback group showed episodes of marked or severe conflict, compared with 21 of 39 (53.8%) control subjects (odds ratio=0.27, 95% confidence interval=0.10 to 0.73). Video feedback produced significant improvements in several other interaction measures and greater infant autonomy. Both groups maintained good infant weight, with no differences between groups. Maternal eating psychopathology was reduced across both groups. CONCLUSIONS: Video-feedback treatment focusing on mother-infant interaction produced improvements in interaction and infant autonomy, and both groups maintained adequate infant weight. To the authors' knowledge, this is the first controlled trial to show key improvements in interaction between mothers with postnatal psychiatric disorders and their infants.

Adult↗
PubMedDate not supplied

Effects of alterations in auditory feedback and speech rate on stuttering frequency.

This study investigated the effects of altered auditory feedback on stuttering frequency during speech production at two different speech rates, Nine stutterers, who exhibited at least 5% dysfluency during a reading task, served as subjects. They read eight different passages (each 300 syllables in length) while receiving four conditions of auditory feedback: nonaltered, masking, delayed, and frequency altered. For each auditory feedback condition, subjects read at both a normal and a fast rate. Results indicated that stuttering frequency was significantly decreased during conditions of delayed and frequency altered auditory feedback at both speech rates (p < 0.05). These findings refute the notion that a slowed speech rate is necessary for fluency enhancement under conditions of altered auditory feedback. Considering previous research and the results of this study, it is proposed that there may be two interdependent factors that are responsible for fluency enhancement: alteration of auditory feedback and modification of speech production.

Adolescent↗
PubMed2004

Growth and pattern of the mammalian neural tube are governed by partially overlapping feedback activities of the hedgehog antagonists patched 1 and Hhip1.

Upregulation of Patched (Ptc), the Drosophila Hedgehog (Hh) receptor in response to Hh signaling limits the range of signaling within a target field by sequestering Hh. In vertebrates, Ptch1 also exhibits ligand-dependent transcriptional activation, but mutants lacking this response show surprisingly normal early development. The identification of Hh-interacting protein 1 (Hhip1), a vertebrate-specific feedback antagonist of Hh signaling, raises the possibility of overlapping feedback controls. We addressed the significance of feedback systems in sonic hedgehog (Shh)-dependent spinal cord patterning. Mouse embryos lacking both Ptch1 and Hhip1 feedback activities exhibit severe patterning defects consistent with an increased magnitude and range of Hh signaling, and disrupted growth control. Thus, Ptc/Ptch1-dependent feedback control of Hh morphogens is conserved between flies and mice, but this role is shared in vertebrates with Hhip1. Furthermore, this feedback mechanism is crucial in generating a neural tube that contains appropriate numbers of all ventral and intermediate neuronal cell types.

Animals↗
PubMed2004

Open-loop feedback increases physical activity of youth.

PURPOSE: The number of youth that meet activity guidelines is decreasing and easy access to reinforcing sedentary behaviors competes with increasing physical activity. In the laboratory, open-loop feedback that used pedometer activity counts to gain access to sedentary alternatives doubled physical activity. This study evaluated the influence of open-loop feedback and reinforcement on physical activity and television (TV) time in a small clinical trial. METHODS: Children (8-12 yr old) were randomized to an open-loop feedback plus reinforcement intervention (N = 11) or no feedback, no reinforcement control (N = 7). Subjects wore an accelerometer for 6 wk and attended meetings to download the accelerometer. Accumulating physical activity counts gave subjects in the open-loop group access to TV time, controlled by a TV Allowance device, with 400 counts = 1 h of TV. The control group had no feedback for activity and free access to TV. RESULTS: The open-loop group had a 24% increase in physical activity, which was greater (P = 0.02) than the control group. TV time of the open-loop group was reduced by 18% or 20 min x d(-1) whereas the control group increased by 13 min x d(-1), but these were not significant changes. The change in time spent watching television was directly related to the change in BMI z-score (r = 0.69, P = 0.002). CONCLUSION: Open-loop feedback increases physical activity in children, thus helping children to achieve physical activity recommendations. Reductions in TV watching may reduce or minimize gains in body weight.

Biofeedback, Psychology↗
PubMed2006

Artificial feedback for remotely supervised training of motor skills.

Electromyographic (EMG) biofeedback can be used to train motor functions at a distance, which makes therapy at home a possibility. To enable patients to train properly without the presence of a therapist, artificial feedback is considered essential. We studied the combined effect of age and timing of artificial feedback on training muscle relaxation in 32 healthy subjects (younger: 20-35 years; older: 55-70 years). All subjects improved their performance significantly (F = 6.1, P<0.001). The effect of different timing of feedback (feedback provided during or after performance) was similar in young and older adults. However, this conclusion should be interpreted with caution owing to the small sample size. It can be argued that the artificial feedback used was too complicated for older adults to interpret. When designing remotely supervised treatment programmes, one should consider carefully the way that artificial feedback is being applied as it may enable (elderly) subjects to train without the presence of a therapist.

Aged↗
PubMed1991

Efficacy of feedback training in long-standing facial nerve paresis.

An efficacious treatment has not been available to patients with aberrant regeneration of the facial nerve as a result of Bell's palsy or after acoustic neuroma excision. This prospective controlled trial examines the efficacy of electromyographic feedback versus mirror feedback as treatment strategies for patients suffering from long-standing (18 months minimum) facial nerve paresis. Twenty-five patients were randomly assigned to electromyography with mirror feedback or mirror feedback alone. Seven rural patients who did not undergo treatment served as controls. At 0, 6, and 12 months, facial motor function was objectively quantified by linear measurement of facial movement, visual assessment of voluntary movement, and electrical measurement of facial nerve response to maximal stimulation. Statistically significant improvements were noted in both electromyography and mirror-feedback groups with respect to symmetry of voluntary movement (P less than .03) and linear measurement of facial expression (P less than .01). The positive results of this controlled trial demonstrate that feedback training in combination with a structured home rehabilitation program is a clinically efficacious treatment for patients with facial nerve paresis.

Adult↗
PubMed2006

Effects of unwanted feedback on synchronized chaotic optical communications.

The effects of unwanted external optical feedback on synchronized chaotic optical communication systems are studied numerically. We consider an open-loop configuration consisting of a transmitter laser with double external optical feedbacks and a receiver laser with optical injection from the transmitter laser. First, including the effects of unwanted optical feedback, the synchronization performances of both the complete synchronization and the generalized synchronization are examined. Then the encoding and decoding performances of the generalized synchronization and the effects of the introduced feedback are investigated, respectively. Finally, we study the control of the unwanted feedback on the dynamics of the transmitter laser and briefly discuss the system security when the transmitter laser is driven to operate in a steady state or periodic oscillation state by the additional feedback.

Journal Article↗
PubMed1999

Reduction in ventilator response to CO2 with relaxation feedback during CO2 rebreathing in normal adults.

BACKGROUND: Previous studies have shown that relaxation biofeedback reduced time on the ventilator for the difficult-to-wean patients. OBJECTIVE: To test the hypothesis that the underlying mechanism of biofeedback ventilator weaning was the reduction of neural respiratory drive (NRD). DESIGN: Prospective, linear regression analysis. SETTING: Critical care medicine department in tertiary health care hospital. SUBJECTS: Fifteen healthy adult volunteers were randomly assigned to the biofeedback group, and 15 healthy adult volunteers were randomly assigned to a control group. INTERVENTIONS: Relaxation feedback was administered while a single variable, PaCO2, was inputted to the respiratory control system and the output measured. While rebreathing 7% CO2/93% O2, the biofeedback group received a baseline session and a relaxation feedback session and the control group received a baseline session and a no feedback session. MEASUREMENTS AND RESULTS: During relaxation feedback, there was a significant (p < 0.001 to p < 0.05) reduction in the slope of minute ventilation (VI), mean inspiratory flow (VT/TI), occlusion pressure in 0.1 s from onset of inspiration (P100), respiration rate (RR), and diaphragm (DA) EMG compared to baseline. We also found the above breathing parameters decreased significantly for relaxation feedback (p < 0.001-0.05), compared to baseline, at maximum end-tidal CO2 (64 +/- 1.2 mm Hg) (all data are expressed as mean +/- SE). The decrease for VI = -4.65 +/- 1.17 L/min, DA EMG = -0.4 +/- 0.21 microV, P100 = -1.13 +/- 0.56 cm H2O, VT/ TI = -144 +/- 82.91 ml/s, and RR = -3.1 +/- 0.79 breaths/min. No significant changes occurred in these parameters for the control group. CONCLUSIONS: We conclude that the addition of the behavioral input of relaxation feedback results in decreasing the values of respiratory parameters that reflect NRD.

Adult↗
PubMed1997

Continuous concurrent feedback degrades skill learning: implications for training and simulation.

In two experiments we investigated the role of continuous concurrent visual feedback in the learning of discrete movement tasks. During practice the learner's actions either were or were not displayed on-line during the action; in both conditions the participant received kinematic feedback about errors afterward. Learning was evaluated in retention tests on the following day. We separated (a) errors in the fundamental spatial-temporal pattern controlled by the generalized motor program from (b) errors in scaling controlled by parameterization processes. During practice concurrent feedback improved parameterization but tended to decrease program stability. Based on retention tests, earlier practice with continuous feedback generally interfered with the learning of an accurate motor program and reduced the stability of time parameterization. Continuous feedback during acquisition degrades the learning of not only closed-loop processes in slower movements (as has been found in earlier studies) but also motor programs and their parameterization in more rapid tasks. Implications for feedback in training and simulation are discussed.

Analysis of Variance↗
PubMed1999

The use of physician financial incentives and feedback to improve pediatric preventive care in Medicaid managed care.

OBJECTIVE: Immunizations and other cost-effective preventive services remain underused by many children, especially those living in poverty. Given the effectiveness of provider-based tracking systems and the widespread use by managed care organizations of financial incentives to influence physician practice patterns, we designed and tested an intervention combining these strategies. We studied whether a system of semiannual assessment and feedback, coupled with financial incentives, could improve pediatric preventive care in a Medicaid health maintenance organization (HMO). METHODOLOGY: We randomly assigned primary care sites serving children in a Medicaid HMO to one of three groups: a feedback group (where physicians received written feedback about compliance scores), a feedback and incentive group (where physicians received feedback and a financial bonus when compliance criteria were met), and a control group. We evaluated compliance with pediatric preventive care guidelines through semiannual chart audits during the years 1993 to 1995. RESULTS: Compliance with pediatric preventive care improved dramatically in the study period. Repeated measures ANOVA demonstrated a significant increase in all three study groups throughout the time in total compliance scores (from 56%-73%), as well as scores for immunizations (from 62%-79%) and other preventive care (from 54%-71%). However, no significant differences were observed between either intervention group and the control group, nor were there any interaction (group-by-time) effects. CONCLUSIONS: Feedback to physicians, with or without financial incentives, did not improve pediatric preventive care in this Medicaid HMO during a time of rapid, secular improvements in care. Possible explanations include the context and timing of the intervention, the magnitude of the financial incentives, and lack of physician awareness of the intervention.

Analysis of Variance↗
PubMed2006

Effects of open-loop feedback on physical activity and television viewing in overweight and obese children: a randomized, controlled trial.

OBJECTIVES: Television viewing and physical inactivity increase the risk of obesity in youth. Thus, identifying new interventions that increase physical activity and reduce television viewing would be helpful in the prevention and treatment of pediatric obesity. This study evaluated the effects of open-loop feedback plus reinforcement versus open-loop feedback alone on physical activity, targeted sedentary behavior, body composition, and energy intake in youth. METHODS: Thirty overweight or obese 8- to 12-year-old children were randomly assigned to an intervention (n = 14) or control group (n = 16). Participants wore accelerometers every day for 8 weeks and attended biweekly meetings to download the activity monitors. For children in the open-loop feedback plus reinforcement (intervention) group, accumulating 400 counts of physical activity on pedometers earned 1 hour of television/VCR/DVD time, which was controlled by a Token TV electronic device. Open-loop feedback control subjects wore activity monitors but had free access to targeted sedentary behavior. RESULTS: Compared with controls, the open-loop feedback plus reinforcement group demonstrated significantly greater increases in daily physical activity counts (+65% vs +16%) and minutes per day of moderate-to-vigorous physical activity (+9.4 vs +0.3) and greater reductions in minutes per day spent in television viewing (-116.1 vs +14.3). The intervention group also showed more favorable changes in body composition, dietary fat intake, and energy intake from snacks compared with controls. Reductions in sedentary behavior were directly related to reductions in BMI, fat intake, snack intake, and snack intake while watching television. CONCLUSIONS: Providing feedback of physical activity in combination with reinforcing physical activity with sedentary behavior is a simple method of modifying the home environment that may play an important role in treating and preventing child obesity.

Behavior Therapy↗
PubMed1970

Behavioral engineering: control of posture by informational feedback.

The effects of informational feedback on a socially undesirable behavior were studied. The feedback was a mild vibrotactile stimulus and the response was slouching. When subjects slouched, a behavioral engineering apparatus provided vibrotactile stimulation to the shoulder. All subjects slouched less when stimulation was provided. A procedural control revealed that slouching will decrease because of the informational aspect of the stimulus consequence and not because of its aversive properties. When the subjects were instructed to slouch, the effects of feedback were reversed: feedback increased, rather than decreased, slouching. These results indicate that the effect of feedback for a response depends on the subject's motivation to perform that response. It is suggested that informational feedback could be used more widely as a therapeutic procedure to modify human behaviors, but only those behaviors that a patient is strongly motivated to change.

Journal Article↗