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PubMed1997

Psychological effects of dietary fat analysis and feedback: a randomized feedback design.

Excess consumption of dietary fat promotes chronic disease such as heart disease and cancer. Dietary analysis and feedback are often used to motivate dietary change; however, little is known about how people process, react to, and use this feedback to change behavior. This study used a randomized feedback design to examine psychological reactions to dietary fat feedback. Subjects were assessed for fat consumption and then randomly assigned to a high, moderate, or low percentage of calories from fat feedback group. Findings indicate that there are strong emotional, cognitive, and behavioral reactions to providing high-fat dietary feedback. Subjects that were told their diets were high in fat reported stronger negative emotional reactions and also reported they had stronger intentions to change than the other two feedback categories. These results are compared with studies providing nonrandomly assigned risk factor feedback.

Adolescent↗

PubMed2006

Audit and feedback and clinical practice guideline adherence: making feedback actionable.

BACKGROUND: As a strategy for improving clinical practice guideline (CPG) adherence, audit and feedback (A&F) has been found to be variably effective, yet A&F research has not investigated the impact of feedback characteristics on its effectiveness. This paper explores how high performing facilities (HPF) and low performing facilities (LPF) differ in the way they use clinical audit data for feedback purposes. METHOD: Descriptive, qualitative, cross-sectional study of a purposeful sample of six Veterans Affairs Medical Centers (VAMCs) with high and low adherence to six CPGs, as measured by external chart review audits. One-hundred and two employees involved with outpatient CPG implementation across the six facilities participated in one-hour semi-structured interviews where they discussed strategies, facilitators and barriers to implementing CPGs. Interviews were analyzed using techniques from the grounded theory method. RESULTS: High performers provided timely, individualized, non-punitive feedback to providers, whereas low performers were more variable in their timeliness and non-punitiveness and relied on more standardized, facility-level reports. The concept of actionable feedback emerged as the core category from the data, around which timeliness, individualization, non-punitiveness, and customizability can be hierarchically ordered. CONCLUSION: Facilities with a successful record of guideline adherence tend to deliver more timely, individualized and non-punitive feedback to providers about their adherence than facilities with a poor record of guideline adherence. Consistent with findings from organizational research, feedback intervention characteristics may influence the feedback's effectiveness at changing desired behaviors.

Journal Article↗

PubMed2004

The learning curve for a colonoscopy simulator in the absence of any feedback: no feedback, no learning.

BACKGROUND: The hypothesis of this study is that working on the simulator without a structured feedback does not change performance; hence, any effects shown after structured feedback would amount to useful learning of the procedure. The aim was to investigate the learning curve for the HT Immersion Medical Colonoscopy Simulator without any structured feedback. This could then be potentially applied to validate the learning curve on the simulator when structured feedback is provided. There are no previous studies on this matter. METHODS: Candidates were asked to perform colonoscopy on the HT Immersion Medical Colonoscopy Simulator. Modules 3 and 4 were used at random. In total, each candidate was asked to perform five consecutive virtual colonoscopies on the same module. These five episodes were collectively referred to as one trial. A time result of 3,600 sec (1 h) was used to denote perforation. No guidance or feedback was given to candidates before, during, or after each procedure. A total of 26 postgraduate doctors were recruited, including nine research fellows, five preregistration house officers, six specialist registrars, and six consultants. Fourteen candidates recorded five attempts each (i.e., one trial each) on the same module of the colonoscopy simulator (14 trials over 70 episodes). Another 12 candidates recorded five attempts (i.e., one trial each) on two modules of the colonoscopy simulator (24 trials over 120 episodes). Hence, 190 episodes were recorded in total, representing 38 trials. RESULTS: There was no improvement in performance on the simulator from first attempt to the fifth in the absence of feedback. If there was any initial gain in any measurable outcome, this was lost in subsequent attempts indicating lack of learning. The outcomes measured included time taken to complete the test, percentage of the mucosa visualized, depth of the instrument inserted, and the path length used. The results were statistically significant for all outcomes. CONCLUSIONS: This study demonstrates that in the absence of feedback, it is not possible to improve performance on the HT Immersion Medical Colonoscopy Simulator. Thus, there is no learning curve for the machine. The information from this study is vital for using the simulators in training and assessment because any improvement in learning curves shown after training on simulators can be presumed to be due to learning the procedure and not the simulator.

Clinical Competence↗

PubMed1993

Does perceptual intake speed reflect intelligent use of feedback in an inspection-time task? The effect of restricted feedback.

To examine whether the development of effective strategies during inspection time (IT) required active learning processes, we gave subjects an IT task involving false feedback. This IT task (ADIT) started at an exposure duration of 20 ms and gradually increased until subjects could reliably discriminate IT stimuli. False feedback about correctness of discrimination was introduced to make the ADIT task particularly difficult for individuals who were attempting to develop and refine an IT-related strategy. There was no difference between ITs derived from the ADIT and a standard IT task (VIT). There were no differences in ITs for subjects given either truthful or false feedback on the ADIT task. However, an interaction did exist between the feedback condition and the two IT tasks. This interaction indicated that subjects with ostensibly better VITs had poorer performance on ADIT, compared with those subjects who had truthful feedback. This finding suggests that false feedback can disrupt effective performance on IT. Self-reported strategy use had a significant independent effect on the observed IT measures. Individuals who reported strategies were not significantly higher in IQ than those who did not report strategies.

Adult↗

PubMed1996

Effects of mood state and favorability of feedback on reactions to performance feedback.

An experimental simulation involving 55 women assessed the main and interactive effects of experimentally induced mood state (positive vs negative) and favorability of performance feedback (positive vs negative) on the perceived accuracy of feedback. The study was conducted in two sessions. During Session I the subjects role-played the position of an advertising agent and worked on an advertising task. In Session II they were administered either a positive or negative mood induction, given positive or negative feedback on the advertising task, and completed a measure of the perceived accuracy of feedback. Regression analyses indicated support for hypothesized main and interactive effects, suggesting that mood state and favorability of feedback interactively affect the perceived accuracy of received feedback.

Adult↗

PubMed2007

Verbal feedback from an expert is more effective than self-accessed feedback about motion efficiency in learning new surgical skills.

BACKGROUND: Teaching of technical surgical skills to undergraduate medical students in a laboratory setting away from the patient is not common practice. Because of the large volume of students and shortage of available teaching faculty new methods of teaching must be developed for this group of trainees. In this study we examined the effectiveness of computer-based video training, different types of computer-based motion efficiency feedback (with and without expert criteria), and expert feedback on learning of a basic technical skill in medical students. METHODS: Forty-five junior medical students were randomized into 3 groups and learned suturing and knot-tying skills. Group A received computer-generated feedback about the economy of their movements. Group B received the same motion economy feedback, as well as expert reference values. Group C received verbal feedback from an expert. All groups were pre-tested, allowed 18 practice trials, and post-tested, and their skill retention was retested after 1 month. Performance was assessed by expert analysis using an objective structured analysis of technical skill and by computer analysis (Imperial College Surgical Assessment Device [ICSAD]). RESULTS: All groups showed improvement from pre-test to post-test. However, only group C showed retention of skill on delayed performance testing. CONCLUSIONS: Verbal feedback from an expert instructor led to lasting improvements in technical skills performance. Providing information about motion efficiency did not lead to similar improvements.

Biofeedback, Psychology↗

PubMed2005

p53-Mdm2 loop controlled by a balance of its feedback strength and effective dampening using ATM and delayed feedback.

When the genomic integrity of a cell is challenged, its fate is determined in part by signals conveyed by the p53 tumour suppressor protein. It was observed recently that such signals are not simple gradations of p53 concentration, but rather a counter-intuitive limit-cycle behaviour. Based on a careful mathematical interpretation of the experimental body of knowledge, we propose a model for the p53 signalling network and characterise the p53 stability and oscillatory dynamics. In our model, ATM, a protein that senses DNA damage, activates p53 by phosphorylation. In its active state, p53 has a decreased degradation rate and an enhanced transactivation of Mdm2, a gene whose protein product Mdm2 tags p53 for degradation. Thus the p53-Mdm2 system forms a negative feedback loop. However, the feedback in this loop is delayed, as the pool of Mdm2 molecules being induced by p53 at a given time will mark for degradation the pool of p53 molecules at some later time, after the Mdm2 molecules have been transcribed, exported out of the nucleus, translated and transported back into the nucleus. The analysis of our model demonstrates how this time lag combines with the ATM-controlled feedback strength and effective dampening of the negative feedback loop to produce limit-cycle oscillations. The picture that emerges is that ATM, once activated by DNA damage, makes the p53-Mdm2 oscillator undergo a supercritical Hopf bifurcation. This approach yields an improved understanding of the global dynamics and bifurcation structure of our time-delayed, negative feedback model and allows for predictions of the behaviour of the p53 system under different perturbations.

Animals↗

PubMed2003

Effects of objective feedback and "single other" or "average other" social comparison feedback on performance judgments and helping behavior.

In two studies, participants received positive or negative feedback about their performance on a verbal task and then provided hints to another person on a subsequent, different task. It was expected that participants would give more helpful hints after positive than after negative feedback but that this would be more apparent when the feedback was based on performance comparisons with the "average participant" than on comparisons with another person or an objective standard. This effect was expected to be mediated by judgments of one's performance on the first task. These predictions were supported. Participants seemed aware of the effect of feedback on their hint choices, and their hint choices did not alter their affect levels. Also, participants receiving comparative (single or aggregated target) feedback exhibited changes in self-ascribed importance of the performance domain. Implications for social comparison theory and self-evaluation maintenance theory are discussed.

Analysis of Variance↗

PubMed1981

Role of feedback mechanism in renal autoregulation and sensing step in feedback pathway.

The unique morphology of the juxtaglomerular complex has resulted in many investigations evaluating its potential physiological roles. One hypothesis that has stimulated considerable interest is that feedback signals originating from distal tubule cells, presumably at the macula densa segment, participate in the phenomenon of renal autoregulation. Data obtained from dog experiments indicate tha autoregulation of single nephron glomerular filtration rate (SNGFR) is most consistently observed when fluid delivery to the early distal tubule is not interrupted. In contrast, techniques that interfere with normal orthograde fluid delivery to the distal nephron have usually resulted in increases in SNGFR and an inability to exhibit appropriate autoregulatory responses to decreases in arterial pressure. There is considerable uncertainty concerning the nature of the intraluminal component of the early distal tubule fluid responsible for initiating feedback responses. The studies reported in this paper have indicated that feedback mediated decreases in stop-flow pressure and SNGFR in response to increases in distal microperfusion rate can occur with a variety of artificial perfusion solutions, including solutions that contain low concentrations of chloride, sodium, or total electrolytes. Microperfusion studies in the rat have demonstrated that feedback mediated decreases in stop-flow pressure can occur in the absence of associated increases in distal tubule fluid chloride concentration. These results are consistent with the concept that some function of distal tubule fluid osmolality or distal tubule solute delivery may participate in the initiation of feedback signals.

Animals↗

PubMed1976

Experimental studies on the positive feedback effect of progesterone, 17 alpha-hydroxyprogesterone and 20 alpha-dihydroprogesterone on the pituitary release of LH and FSH in the human female. The estrogen priming of the progesterone feedback on pituitary gonadotropins in the eugonadal woman.

Administration of progesterone eugonadal women during the midfollicular phase of the menstrual cycle failed to induce a positive feedback effect on the serum concentrations of LH and FSH. The levels of estradiol in serum decreased following the injection of progesterone without a parallel change in LH and FSH concentrations indicating a direct ovarian effect of the exogenous progesterone. In the late follicular phase of the cycle, when preovulatory levels of estradiol were present in serum, or under a ethinyl estradiol treatment progesterone was able to induce an LH discharge indicating the requirement of an estradiol priming of the positive feedback of progesterone in eugonadal women. In order to establish the time required for a sufficient estrogen priming with preovulatory levels of estradiol in serum 3 mg of estradiol-benzoate were administered i.m. 1, 12 and 24 h prior to the administration of 30 mg of microcristalline progesterone in the midfollicular phase of the menstrual cycle, when progesterone alone did not cause an LH surge. Only when estradiol-benzoate was injected 24 h prior to the progesterone administration an LH surge reproducible in time course and magnitude occurred. Administration of estradiol-benzoate alone under these conditions did not cause an LH surge within the elapse of time after the injection when the progesterone induced LH surge occurred. Thus, these experiments demonstrate that a defined estrogen priming is required for the positive feedback effect of progesterone on the gonadotropin release in eugonadal women. Furthermore, progesterone levels in serum of about only 1--2 ng/ml were required for the induction of an LH surge indicating that under physiological conditions progesterone may have an supplementory effect on the primarily estradiol induced LH midcycle peak. 17-hydroxyprogesterone administered during the mid follicular phase of the menstrual cycle and under pretreatment with ethinyl estradiol failed to induce a positive feedback effect on the serum concentrations of LH and FSH, indicating that this steroid does not play a regulatory role on the midcycle LH release in women. 20alpha-dihydroprogesterone administered under the same experimental conditions as 17-hydroxyprogesterone seems to be able to induce an LH surge in serum provided there is an adequate estrogen priming.

20-alpha-Dihydroprogesterone↗

PubMed2006

A model for educational feedback based on clinical communication skills strategies: beyond the "feedback sandwich".

BACKGROUND: Feedback is an essential tool in medical education, and the process is often difficult for both faculty and learner. There are strong analogies between the provision of educational feedback and doctor-patient communication during the clinical encounter. DESCRIPTION: Relationship-building skills used in the clinical setting-Partnership, Empathy, Apology, Respect, Legitimation, Support (PEARLS)-can establish trust with the learner to better manage difficult feedback situations involving personal issues, unprofessional behavior, or a defensive learner. Using the stage of readiness to change (transtheoretical) model, the educator can "diagnose" the learner's stage of readiness and employ focused interventions to encourage desired changes. EVALUATION: This approach has been positively received by medical educators in faculty development workshops. CONCLUSIONS: A model for provision of educational feedback based on communication skills used in the clinical encounter can be useful in the medical education setting. More robust evaluation of the construct validity is required in actual training program situations.

Communication↗

PubMed1984

Does prolactin modify testosterone feedback in the hamster? Suppression of plasma prolactin inhibits photoperiod-induced decreases in testosterone feedback sensitivity.

The hormonal changes during the photoperiodically driven annual reproductive cycle of the male golden hamster can be explained partially by a change in the sensitivity of the hypothalamo-pituitary axis to negative feedback by testosterone (T). The present studies test the hypothesis that the increases in plasma levels of LH and FSH that follow photo-stimulation are due to decreasing feedback sensitivity and examine if this change in sensitivity is dependent upon increasing PRL levels. Adult males were exposed to a lighting schedule of 5 h of light, 19 h of darkness (5:19) for 12 weeks to induce gonadal regression. The animals were castrated; treated with an inhibitor of PRL release, bromocriptine (CB-154), or oil; and received a Silastic capsule that was empty or filled with T. Subsequently, the animals were transferred to 14:10 and killed 9 or 31 days later. There were no significant changes in FSH and LH in animals receiving oil injections and empty implants between days 9 and 31, suggesting no steroid-independent changes in gonadotropin secretion during this time period. However, 4-mm T implants were more effective in suppressing LH and FSH levels on day 9 than on day 31. This suggests that there is a gradual decrease in feedback sensitivity to T following photostimulation. T was more effective in inhibiting LH and FSH levels in CB-154-treated than in oil-treated animals on both day 9 and day 31. Thus, increases in PRL release are instrumental in causing decreases in feedback sensitivity following photostimulation.

Animals↗

PubMed1979

Effect of information feedback on temporal discrimination in concurrent and post-feedback measures.

College students estimated time intervals (5, 6, 7, 8, and 9 sec.) where one group (N = 20) received information feedback in terms of actual interval durations and a second group (N = 18) received no information. Theshold measures were then taken for all subjects using the method of constant stimuli (comparison stimuli of 5, 6, 7, 8, and 9 sec. and a 7-sec. standard). In addition to increased accuracy and consistency of judgments, the feedback group showed a decreasing Weber fraction during the estimation phase, while the Weber fraction for the no-feedback group increased. The feedback group retained only a slight advantage in subsequent threshold measures; group differences in difference thresholds and derived nonparametric estimates of d' were nonsignificant.

Differential Threshold↗

PubMed2002

Modeling of human posturokinetic movements by a linear feedback system: relations among feedback coefficients.

This study describes a method of modeling human trunk and whole body backward bending and suggests a possible neural control strategy. The hypothesis was that the control system can be modeled as a linear feedback system, in which the torque acting at a given joint is a function of the state variables (angular positions and angular velocities). The linear system enabled representation of the feedback system by a gain matrix. The matrix was computed from the kinematics recorded by a movement analysis system and from the joint torques calculated by inverse dynamics. To validate the control model, a comparison was made between the angular kinematics yielded by the model and the experimental data. Moreover, for all subjects, the same relationships between feedback coefficients were found although gain values were different. The study showed that the feedback system is an appropriate model of the strategy from performing an accurate controlled trunk or whole body backward bending in the sagittal plane.

Adult↗

PubMed1994

Digital feedback suppression (DFS). Characterization of feedback-margin improvements in a DFS hearing instrument.

The introduction of a new power behind-the-ear hearing instrument equipped with an integrated digital feedback suppression (DFS) system, based on adaptive, digital signal processing, creates the need for new methods for evaluating the characteristics of this new technology. A special measuring method based on determination of the complex loop gain of the DFS instrument and the associated feedback path is described. This method yields information about the static feedback-margin improvement due to the DFS system, and the method is usable especially in connection with measurements on real ears. It requires fairly advanced test facilities, including a dual-channel FFT analyzer and, by preference, an anechoic room. Loop gain measurements on the new DFS power behind-the-ear hearing instrument show encouraging results. Groups of profoundly hearing-impaired children and adults were tested, and static feedback-margin improvements in the order of 10 dB for the new DFS power hearing instrument were seen. Variations were largest for groups using own ear moulds and individually fitted instruments.

Acoustic Stimulation↗

PubMed1991

Improving feedback on student papers: a quantitative method which aids marking and gives valid feedback.

A quantifying method of marking was developed to aid in consistent and thorough marking of student papers and to improve the manner and validity of feedback. This feedback is on common technical writing skills. Giving feedback on technical writing skills, as opposed to concentrating on critical thinking skills, is defended. The benefits and purposes of this marking method are further developed. Implementation of the method is outlined, and a completed Quantitative Feedback form is demonstrated. Through evaluation, the method has been found effective for aiding marking and for clearly identifying strengths and weaknesses in writing.

Education, Nursing↗

PubMed1999

Practice visits as a tool in quality improvement: mutual visits and feedback by peers compared with visits and feedback by non-physician observers.

OBJECTIVE: To evaluate and compare the effects of two programmes of assessment of practice management in a practice visit: mutual visits and feedback by peers compared with visits and feedback by non-physician observers. DESIGN: Prospective, randomised intervention study, with follow up after one year. SETTING: General practices in the Netherlands in 1993 and 1994. SUBJECTS: A total of 90 general practitioners (GPs) in 68 practices; follow up after one year comprised 81 GPs in 62 practices. MAIN MEASURES: Scores on indicators and dimensions of practice management in the visit instrument to assess practice management and organisation (a validated Dutch method to assess practice management in a practice visit). Change was defined as the difference in score between the first visit and the visit after one year on 208 indicators and on 33 dimensions of practice management. RESULTS: Data of 44 mutual visits by peers were compared with data of 46 visits by non-physician observers. After a year both programmes showed improvements on many aspects of practice management, but different aspects changed in each of the two programmes. After mutual practice visits, GPs scored significantly higher on content of the doctor's bag, on collaboration with colleagues, on collaboration with other care providers, and on accessibility of patient information than after a visit by a non-physician observer. The visits by non-physician observers resulted in a higher score on extent of use of records and on assessment on outcome and year report. CONCLUSION: Change after mutual practice visits and feedback by peers is more marked than after a visit and feedback by a non-physician observer.

Family Practice↗

PubMed1975

An analysis of a performance feedback system: the effects of timing and feedback, public posting, and praise upon academic performance and peer interaction.

In the first experiment, after establishing baseline composition rates in each classroom, timing (announcing time limits) and feedback (student self-scoring) were introduced followed by the introduction, removal, and reintroduction of public posting of highest scores. Timing and feedback improved story writing performance and public posting of highest scores improved performance even further in both classrooms. Teacher praise produced further improvement in one classroom but had no effect on performance in the other. Changes in on-task behavior paralleled changes in writing rate. Comments made by children concerning their own work or work of their peers were recorded throughout the experiment. Although the baseline rate of performance comments was almost zero, the introduction of each variable markedly increased the rate of performance comments. In the second experiment, baseline rates on reading and language exercises were established in a fifth-grade classroom. The entire performance feedback system was introduced on a multiple baseline across the two behaviors and then removed during the final phase of the experiment. Introducing the system improved performance on both tasks. These results further increased the generality of some of the findings of the previous experiment and of previous research on the efficacy of the experimental package of timing, feedback, public posting, and praise.

Journal Article↗