Does habituation really happen? Investigation of psycho-biological responses to body exposure in bulimia nervosa

Are within- and between-session changes in distress associated with treatment outcomes? Findings from two clinical trials of exposure for eating disorders

OBJECTIVE

Imaginal exposure is a novel intervention for eating disorders (EDs) that has been investigated as a method for targeting ED symptoms and fears. Research is needed to understand mechanisms of change during imaginal exposure for EDs, including whether within- and between-session distress reduction is related to treatment outcomes.

METHOD

Study 1 tested four sessions of online imaginal exposure (N = 143). Study 2 examined combined imaginal and in vivo exposure, comprising six imaginal exposure sessions (N = 26). ED symptoms and fears were assessed pre- and posttreatment, and subjective distress and state anxiety were collected during sessions.

RESULTS

Subjective distress tended to increase within-session in both studies, and within-session reduction was not associated with change in ED symptoms or fears. In Study 1, between-session reduction of distress and state anxiety was associated with greater decreases in ED symptoms and fears pre-to posttreatment. In Study 2, between-session distress reduction occurred but was not related to outcomes.

CONCLUSIONS

Within-session distress reduction may not promote change during exposure for EDs, whereas between-session distress reduction may be associated with better treatment outcomes. These findings corroborate research on distress reduction during exposure for anxiety disorders. Clinicians might consider approaches to exposure-based treatment that focus on distress tolerance and promote between-session distress reduction.

Body exposure and vocal analysis: validation of fundamental frequency as a correlate of emotional arousal and valence

Introduction

Vocal analysis of fundamental frequency (f0) represents a suitable index to assess emotional activation. However, although f0 has often been used as an indicator of emotional arousal and different affective states, its psychometric properties are unclear. Specifically, there is uncertainty regarding the validity of the indices of f0_mean and f0_{variabilitymeasures} (f0_dispersion, f0_range, and f0_SD) and whether higher or lower f0 indices are associated with higher arousal in stressful situations. The present study therefore aimed to validate f0 as a marker of vocally encoded emotional arousal, valence, and body-related distress during body exposure as a psychological stressor.

Methods

N = 73 female participants first underwent a 3-min, non-activating neutral reference condition, followed by a 7-min activating body exposure condition. Participants completed questionnaires on affect (i.e., arousal, valence, body-related distress), and their voice data and heart rate (HR) were recorded continuously. Vocal analyses were performed using Praat, a program for extracting paralinguistic measures from spoken audio.

Results

The results revealed no effects for f0 and state body dissatisfaction or general affect. F0_mean correlated positively with self-reported arousal and negatively with valence, but was not correlated with HR_mean/maximum. No correlations with any measure were found for any f0_{variabililtymeasures}.

Discussion

Given the promising findings regarding f0_mean for arousal and valence and the inconclusive findings regarding f0 as a marker of general affect and body-related distress, it may be assumed that f0_mean represents a valid global marker of emotional arousal and valence rather than of concrete body-related distress. In view of the present findings regarding the validity of f0, it may be suggested that f0_mean, but not f0_{variabilitymeasures}, can be used to assess emotional arousal and valence in addition to self-report measures, which is less intrusive than conventional psychophysiological measures.

Efficacy and mechanisms of change in exposure-based and cognitive stand-alone body image interventions in women with overweight and obesity

OBJECTIVE

Body dissatisfaction is highly prevalent in overweight and obesity, while evidence for the efficacy of body image interventions is still scarce. This interventional pilot study investigates the efficacy and mechanisms of change of two stand-alone body image interventions in women with overweight and obesity.

METHODS

Women with overweight and obesity (n = 76) were randomly assigned to five weekly sessions of either a mirror exposure (ME) or a cognitive restructuring intervention (CR) or to a wait-list control group (WCG). Primary outcome measures were self-reported body dissatisfaction and interview-based shape concerns; depression, self-esteem and emotional eating served as secondary outcome measures. Experimental paradigms were used prior to and after the interventions to analyze possible mechanisms of change: (a) Implicit Associations Tests to assess weight-related attitudes (b) eye-tracking experiments to assess visual processing of body pictures and (c) a thought-sampling procedure to assess body-related cognitions and arousal.

RESULTS

According to intent-to-treat analyses using linear mixed-models, both interventions lead to significant improvements in body image, while there were no changes in the WCG. Different mechanisms of change were identified.

CONCLUSIONS

Both types of interventions might be effective in the reduction of self-reported body dissatisfaction and interview-based shape concerns in overweight and obesity. However, as different mechanisms drive the effects, future research should clarify which individual might best benefit from which intervention.

Die Spiegelkonfrontationstherapie zur Behandlung von Körperbildstörungen bei Essstörungen – Evidenz, Wirkmechanismen und Vorgehensweise

Zusammenfassung. Körperbildprobleme sind ein Kernmerkmal von Essstörungen. Daher gilt eine Verbesserung des Körperbildes bei der Behandlung von Essstörungen als zentrales Therapieziel. Verschiedene empirische Befunde weisen auf die Spiegelkonfrontation als wirksame Methode zur Reduktion von Körperbildstörungen hin. Ziel dieses Übersichtsartikels ist es, den aktuellen Stand der wissenschaftlichen Literatur zum Thema Spiegelkonfrontationstherapie bei Essstörungen darzulegen. Insbesondere sollen die Wirksamkeitsstudien getrennt für nicht-klinische, körperunzufriedene Gruppen mit und ohne Übergewicht sowie die verschiedenen Essstörungsgruppen systematisiert und unterschiedliche Vorgehensweisen beschrieben werden. Der Übersichtsartikel liefert Hinweise dafür, dass die Spiegelkonfrontationstherapie bei Hochrisikogruppen mit erhöhter Körperunzufriedenheit sowie bei Essstörungen zu positiven Veränderungen hinsichtlich der kognitiv-affektiven und behavioralen Komponente des Körperbildes führt. Jedoch mangelt es insgesamt an randomisiert-kontrollierten Studien, die die Wirksamkeit der Spiegelkonfrontationstherapie mit ausreichend großen Stichproben gezielt untersuchen – vor allem bei der Anorexia nervosa. Der Übersichtsartikel schließt mit einer Diskussion über mögliche Wirkmechanismen, (Kontra–)‌Indikationen und einem Ausblick für zukünftige Forschung ab.

What happens in the course of positive mirror exposure? Effects on eating pathology, body satisfaction, affect, and subjective physiological arousal in patients with anorexia and bulimia nervosa

OBJECTIVE

Mirror exposure (ME) is a therapeutic technique to improve body image disturbance. However, evidence on the effectiveness of different forms of ME in clinical populations is lacking. The present study therefore analysed effects of ME on trait-like and state measures of body image in patients with anorexia nervosa (AN) and bulimia nervosa (BN).

METHOD

The present study therefore analysed effects of ME on trait-like and state measures of body image in patients with anorexia nervosa (AN) and bulimia nervosa (BN). In total, 47 inpatients underwent 3 ME sessions guided by a therapist, with instructions to exclusively verbalise positively about their whole body. Participants completed questionnaires on trait-like eating pathology and body image at the start and end of the study, and instruments on state affect and body satisfaction were administered directly before and after each ME session. Subjective physiological arousal and emotional valence relating to each body part were assessed within each session.

RESULTS

The results indicate significant improvements in eating pathology and body image regarding trait-like measures in patients with AN and BN. Concerning state measures, negative affect significantly decreased and body satisfaction increased during ME. Physiological arousal decreased and positively valenced emotions relating to the various body parts increased.

CONCLUSIONS

These findings suggest that positively verbalising about one's body during ME improves eating pathology, body image, affect, and subjective physiological arousal, and thus seems to be an effective form of ME.

Body exposure, its forms of delivery and potentially associated working mechanisms: How to move the field forward

Background

Body image disturbance (BID) is a hallmark feature of eating disorders (EDs) and has proven to be involved in their etiology and maintenance. Therefore, the targeting of BID in treatment is crucial, and has been incorporated in various treatment manuals. One of the most common techniques in the treatment of BID is body exposure (BE), the confrontation with one’s own body. BE has been found to be effective in individuals with EDs or high body dissatisfaction. However, BE is applied in a multitude of ways, most of which are based on one or a combination of the hypothesized underlying working mechanisms, with no differential effectiveness known so far.

Method

The aim of this paper is to selectively review the main hypothesized working mechanisms of BE and their translation into therapeutic approaches.

Results and Conclusion

Specifically, we underline that studies are needed to pinpoint the proposed mechanisms and to develop an empirically informed theoretical model of BE. We provide a framework for future studies in order to identify working mechanisms and increase effectiveness of BE.

Effects of full-body mirror exposure on eating pathology, body image and emotional states: Comparison between positive and negative verbalization

Mirror exposure (ME) is an effective technique to improve body image. However, evidence on the underlying mechanisms and the optimal verbalization instruction during ME is lacking. Therefore, this experimental study analyzed mechanisms of ME and therapeutic outcomes by comparing positive (PV) and negative (NV) full-body verbalization. N = 73 healthy females were randomized to a PV or an NV condition. PV participants verbalized positively while NV participants verbalized negatively about their whole body. Each participant underwent three standardized ME sessions. Before and after each ME session, positive affect, negative affect and body satisfaction were assessed. Before the first and after the third ME, participants completed questionnaires on cognitive-affective and behavioral aspects of body image, eating pathology and self-esteem. Regarding within-ME changes, the results indicate that positive affect and body satisfaction decreased while negative affect increased in the NV group but not in the PV group. In contrast, regarding between-ME changes, decreased negative affect as well as positive affect and increased body satisfaction were observed in both groups. However, eating pathology remained stable, whereas body-checking behavior increased and the PV condition was followed by higher levels of self-esteem compared to the NV condition. These findings suggest that both PV and NV improve negative affect and body satisfaction between-ME, and thus seem to be effective ME instructions. Given that NV led to increased negative affect within-ME and did not influence self-esteem, PV might represent the favorable instruction during ME for body-satisfied women.

Computer Based Body Exposure in Adolescents With Anorexia Nervosa: A Study Protocol

Body dissatisfaction is a core feature of eating disorders (EDs) and plays an essential role in the development and maintenance of anorexia nervosa (AN). In the current study, a computer based body exposure intervention is conducted and evaluated regarding short-term effects on body dissatisfaction, psychopathology, viewing patterns, and stress reactivity. Within a randomized controlled trial (RCT) female adolescents and young women with AN are either receiving the intervention or treatment as usual (TAU). Furthermore, in a transdiagnostic approach, a highly body-dissatisfied group of clinical control participants obtaining the intervention will be surveyed to identify AN-specific processes. The standardized four-session body exposure intervention using photographs of the own body is adapted from a manualized body image treatment program for computer use. Psychopathology (body dissatisfaction, body image avoidance, body checking, depression, anxiety) is assessed via standardized questionnaires before and after the intervention. During each session, attentional biases regarding one's own body are measured via eye tracking, stress levels are measured via subjective ratings, heart rate variability, as well as salivary cortisol and alpha amylase. Between- and within-subject effects will be assessed. The pilot study aims to identify short-term effects of the intervention on body dissatisfaction and attentional bias, as well as to investigate the potential underlying mechanism of physiological habituation.

Vocal arousal: a physiological correlate of body distress in women with overweight and obesity

PURPOSE

Numerous studies highlight the relevance of body image in the development and maintenance of overweight and obesity mostly using self-reported data. Given the importance of physiological assessment methods, the present study aimed at investigating vocally encoded emotional arousal as a correlate of body distress in women with overweight and obesity.

METHODS

Cognitions of women with overweight and obesity (OW; n = 22) as well as normal weight controls (NW; n = 22) were assessed by means of a thought-sampling procedure during a mirror exposure and a control condition. Fundamental frequency (f0) as a marker of vocally encoded emotional arousal as well as verbalized body-related cognitions were analyzed during this experimental task.

RESULTS

A stronger increase in f0 between the control and the mirror exposure condition was found in OW compared to NW. Furthermore, there were significant positive correlations between vocally encoded emotional arousal and various measures of body image.

CONCLUSION

The findings support the utility of vocally encoded emotional arousal as an objective physiological correlate of the evaluative dimension of body image in women with overweight and obesity.

LEVEL OF EVIDENCE

Level I, experimental study.

A systematic and methodological review of attentional biases in eating disorders: Food, body, and perfectionism

OBJECTIVE

The current systematic and methodological review aimed to critically review existing literature utilizing implicit processing, or automatic approach- and/or avoidance-related attentional biases between eating disorder (ED) and nonclinical samples, which (a) highlights how psychophysiological methods advance knowledge of ED implicit bias; (b) explains how findings fit into transdiagnostic versus disorder-specific ED frameworks; and (c) suggests how research can address perfectionism-related ED biases.

METHOD

Three databases were systematically searched to identify studies: PubMed, Scopus, and PsychInfo electronic databases. Peer-reviewed studies of 18- to 39-year-olds with both clinical ED and healthy samples assessing visual attentional biases using pictorial and/or linguistic stimuli related to food, body, and/or perfectionism were included.

RESULTS

Forty-six studies were included. While behavioral results were often similar across ED diagnoses, studies incorporating psychophysiological measures often revealed disease-specific attentional biases. Specifically, women with bulimia nervosa (BN) tend to approach food and other body types, whereas women with anorexia nervosa (AN) tend to avoid food as well as overweight bodies.

CONCLUSIONS

Further integration of psychophysiological and behavioral methods may identify subtle processing variations in ED, which may guide prevention strategies and interventions, and provide important clinical implications. Few implicit bias studies include male participants, investigate binge-eating disorder, or evaluate perfectionism-relevant stimuli, despite the fact that perfectionism is implicated in models of ED.

Cognitive-Emotional Involvement During Mirror Exposure Is Not Accompanied by Physiological Activation in Binge Eating Disorder

Body image interventions have been shown to reduce self-reported cognitive-emotional facets of body image disturbance in binge eating disorder (BED). However, more objective assessment methods are required to evaluate the effects of these interventions. Therefore, the present study aimed at investigating the usefulness of vocally encoded emotional arousal as physiological correlate of body dissatisfaction during mirror exposure in women with BED. Women with BED (n = 60) and weight-matched controls (CG; n = 60) participated in an experimental thought-sampling procedure including a mirror exposure and a control condition in a repeated-measures design. Fundamental frequency as a vocal correlate of emotional arousal as well as negative, neutral, and positive body-related cognitions during both conditions were analyzed. In line with our hypotheses, the BED group verbalized more negative, and less positive and neutral body-related cognitions during the mirror exposure condition compared to the CG. Contrary to our hypotheses, though, there was a stronger increase in physiological arousal between the control and the mirror exposure condition in the CG relative to the BED group. Furthermore, a significant negative correlation between fundamental frequency and the severity of cognitive-emotional body image disturbances emerged. The findings indicate a cognitive-emotional over-involvement with physical appearance during mirror exposure in women with BED compared to weight-matched controls in the absence of a corresponding physiological pattern. Results are discussed in terms of an impaired ability of women with BED to show adequate physiological responses to body-related stress. In addition, methodological recommendations for future research are presented.

Expand your body when you look at yourself: The role of the posture in a mirror exposure task

Mirror exposure (ME) is one of the main components of the treatment of patients with eating disorders symptomatology and it has shown its effectiveness in improving several outcomes (e.g., body dissatisfaction). However, the study as to what body posture should be adopted to maximize its effectiveness has been neglected. From embodied cognition and emotion theories, the adoption of an expansive (vs. contractive) body posture has been associated with positive changes in cognitive and emotional responses. The objective of this study was to analyze the effect of adopting an expansive (vs. contractive) posture before an ME task on body-related emotions and cognitions, as well as to analyze the possible moderator and mediator variables of these relationships. The sample was composed of 68 women (age: M = 21.74, SD = 3.12) with high scores on body dissatisfaction. Participants were randomly assigned to the expansive or contractive condition, where the openness of the arms/legs and the back position were manipulated. Posture was monitored by an electronic device and participants filled out several self-reported measures. ANCOVAs, moderation, mediation, and moderated mediated analyses were performed. Results showed that women in the expansive condition showed higher positive emotions after the ME. Moreover, exploratory analyses showed that adopting an expansive posture improved positive emotions, leading to improvements in negative emotions, body image satisfaction, and appraisal of the person’s own body. Psychological interventions should explore the value of holding an expansive posture before the ME in women with body dissatisfaction.