Body size estimation in eating disorder patients: testing the video distortion method on a life-size screen

Comparison of body image evaluation by virtual reality and paper-based figure rating scales in adolescents with anorexia nervosa: retrospective study

PURPOSE

Assessment of the symptoms of body image disorder (BID) is crucial in anorexia nervosa (AN). Recent technological advancements such as virtual reality (VR) have improved the visual perception with 3D avatars and the feeling to be the avatar with the immersive conditions. This retrospective study examines the hypothesis that VR with standardized 3D avatars would improve body image perception and then body image evaluation by adolescents with AN, compared to the paper-based figure rating scales (FRS).

METHODS

Data of 31 female adolescents with AN were retrospectively studied. Paired data of perceived and desired body forms in addition to body perception index (BPI) (p = 0.2) and body dissatisfaction (p = 0.6), obtained by both VR and FRS were compared. Furthermore, correlation with validated psychometric questionnaires was also studied. Head-tracking technology allowed for the implicit measurement of explicit choices of patients.

RESULTS

Participants with AN overestimated own body size regardless of the assessment tool used. BPI and body dissatisfaction did not differ significantly between FRS and VR. VR-based evaluation was correlated with the psychometric parameters BID and body dissatisfaction. Head tracking revealed significantly longer participant engagement with avatars representing malnutrition and underweight states, while those least engaged corresponded to obesity.

CONCLUSIONS

Results of BID evaluation by VR standardized 3D avatars are comparable to those obtained by paper-based FRS. These findings suggest that comparable results obtained by both tools of evaluation reflect primarily the role of affective-cognitive perturbation in BID. The perceptive component could be better evaluated using biometric-enhanced assessment tools.

LEVEL OF EVIDENCE

Level V, cross-sectional descriptive study (evaluation data retrospectively studied).

The Representation of Body Size: Variations With Viewpoint and Sex

Perceived body size is a fundamental construct that reflects our knowledge of self and is important for all aspects of perception, yet how we perceive our bodies and how the body is represented in the brain is not yet fully understood. In order to understand how the brain perceives and represents the body, we need an objective method that is not vulnerable to affective or cognitive influences. Here, we achieve this by assessing the accuracy of full-body size perception using a novel psychophysical method that taps into the implicit body representation for determining perceived size. Participants were tested with life-size images of their body as seen from different viewpoints with the expectation that greater distortions would occur for unfamiliar views. The Body Shape Questionnaire was also administered. Using a two-alternative forced choice design, participants were sequentially shown two life-size images of their whole body dressed in a standardized tight-fitting outfit seen from the front, side, or back. In one image, the aspect ratio (with the horizontal or vertical dimension fixed) was varied using an adaptive staircase, while the other was undistorted. Participants reported which image most closely matched their own body size. The staircase honed in on the distorted image that was equally likely as the undistorted photo to be judged as matching their perception of themselves. From this, the perceived size of their internal body representation could be calculated. Underestimation of body width was found when the body was viewed from the front or back in both sexes. However, females, but not males, overestimated their width when the body was viewed from the side. Height was perceived accurately in all views. These findings reveal distortions in perceived size for healthy populations and show that both viewpoint and sex matter for the implicit body representation. Though the back view of one’s body is rarely–if ever–seen, perceptual distortions were the same as for the front view. This provides insight into how the brain might construct its representation of three-dimensional body shape.

The visual cues that drive the self-assessment of body size: Dissociation between fixation patterns and the key areas of the body for accurate judgement

A modified version of the bubbles masking paradigm was used in three experiments to determine the key areas of the body that are used in self-estimates of body size. In this paradigm, parts of the stimuli are revealed by several randomly allocated Gaussian "windows" forcing judgements to be made based on this partial information. Over multiple trials, all potential cues are sampled, and the effectiveness of each window at predicting the judgement is determined. The modified bubbles strategy emphasises the distinction between central versus edge cues and localises the visual features used in judging one's own body size. In addition, eye-movements were measured in conjunction with the bubbles paradigm and the results mapped onto a common reference space. This shows that although observers fixate centrally on the torso, they are actually directing their visual attention to the edges of the torso to gauge body width as an index of body size. The central fixations are simply the most efficient way of positioning the eye to make this estimation. Inaccurate observers are less precise in their central fixations and do not evenly allocate their attention to both sides of the torso's edge, illustrating the importance of efficiently sampling the key information.

Patients' experiences from basic body awareness therapy in the treatment of binge eating disorder -movement toward health: a phenomenological study

BACKGROUND

Binge Eating Disorder (BED) is the most common eating disorder. Patients with BED are often not diagnosed, nor offered adequate specific treatment. A great number of those who receive recommended treatment do not recover over time. More knowledge about central aspects of BED, and treatments that specifically target such aspects is needed. Previous research has linked body experience to the development and maintenance of eating disorders, as well as influencing treatment results and the risk of relapse. The aim of this study was to explore how patients with BED experience Basic Body Awareness Therapy (BBAT), which is a psychomotor physiotherapy treatment addressing body experience.

METHOD

In this phenomenological study, we interviewed two patients with BED in depth during and after treatment. Video observations of treatment sessions and logs written by the patients were used as supporting data. The analysis was guided by Van Manen's hermeneutic phenomenology.

RESULTS

A meaning structure was identified: "On the way from the body as a problem to the body as a possibility." The two participants that besides BED also had a history of childhood trauma, perceived BBAT as a process of getting to know their own bodies in new ways, and described that the way they related to their own body changed as did aspects of their way of being. These changes were prominent when the participants described emotions, movement, pain, calmness, and self-experience, and interwoven with relational aspects as well as practices in everyday life.

CONCLUSION

The present results indicate that BBAT stimulated body experience in a way that opened new possibilities for two participants with BED, and hence that BBAT can improve the health status of BED patients also suffering from childhood trauma.

Distorted body image influences body schema in individuals with negative bodily attitudes

There is now a considerable body of evidence to suggest that internal representations of the body can be meaningfully separated into at least two general levels; body image as a perceptual construct and body schema as a motor metric. However, recent studies with eating disordered individuals have suggested that there may in fact be more interaction between these two representations than first thought. We aimed to investigate how body image might act to influence body schema within a typical, healthy population. 100 healthy adult women were asked to judge the smallest gap between a pair of sliding doors that they could just pass through. We then determined whether these estimates were sufficient to predict the size of the smallest gap that they could actually pass through, or whether perceptual and attitudinal body image information was required in order to make these predictions. It was found that perceptual body image did indeed mediate performance on the egocentric (but not allocentric) motor imagery affordance task, but only for those individuals with raised body image concerns and low self-esteem; body schema was influenced by both the perceptual and attitudinal components of body image in those with more negative bodily attitudes. Furthermore, disparities between perceived versus actual size were associated with body parts that had larger variations in adipose/muscle-dependent circumference. We therefore suggest that it may be the affective salience of a distorted body representation that mediates the degree to which it is incorporated into the current body state.

Body size estimation in women with anorexia nervosa and healthy controls using 3D avatars

A core feature of anorexia nervosa is an over-estimation of body size. However, quantifying this over-estimation has been problematic as existing methodologies introduce a series of artefacts and inaccuracies in the stimuli used for judgements of body size. To overcome these problems, we have: (i) taken 3D scans of 15 women who have symptoms of anorexia (referred to henceforth as anorexia spectrum disorders, ANSD) and 15 healthy control women, (ii) used a 3D modelling package to build avatars from the scans, (iii) manipulated the body shapes of these avatars to reflect biometrically accurate, continuous changes in body mass index (BMI), (iv) used these personalized avatars as stimuli to allow the women to estimate their body size. The results show that women who are currently receiving treatment for ANSD show an over-estimation of body size which rapidly increases as their own BMI increases. By contrast, the women acting as healthy controls can accurately estimate their body size irrespective of their own BMI. This study demonstrates the viability of combining 3D scanning and CGI techniques to create personalised realistic avatars of individual patients to directly assess their body image perception.

Depictive and metric body size estimation in anorexia nervosa and bulimia nervosa: A systematic review and meta-analysis

A distorted representation of one's own body is a diagnostic criterion and core psychopathology of both anorexia nervosa (AN) and bulimia nervosa (BN). Despite recent technical advances in research, it is still unknown whether this body image disturbance is characterized by body dissatisfaction and a low ideal weight and/or includes a distorted perception or processing of body size. In this article, we provide an update and meta-analysis of 42 articles summarizing measures and results for body size estimation (BSE) from 926 individuals with AN, 536 individuals with BN and 1920 controls. We replicate findings that individuals with AN and BN overestimate their body size as compared to controls (ES=0.63). Our meta-regression shows that metric methods (BSE by direct or indirect spatial measures) yield larger effect sizes than depictive methods (BSE by evaluating distorted pictures), and that effect sizes are larger for patients with BN than for patients with AN. To interpret these results, we suggest a revised theoretical framework for BSE that accounts for differences between depictive and metric BSE methods regarding the underlying body representations (conceptual vs. perceptual, implicit vs. explicit). We also discuss clinical implications and argue for the importance of multimethod approaches to investigate body image disturbance.

Perceived face size in healthy adults

Perceptual body size distortions have traditionally been studied using subjective, qualitative measures that assess only one type of body representation-the conscious body image. Previous research on perceived body size has typically focused on measuring distortions of the entire body and has tended to overlook the face. Here, we present a novel psychophysical method for determining perceived body size that taps into implicit body representation. Using a two-alternative forced choice (2AFC), participants were sequentially shown two life-size images of their own face, viewed upright, upside down, or tilted 90°. In one interval, the width or length dimension was varied, while the other interval contained an undistorted image. Participants reported which image most closely matched their own face. An adaptive staircase adjusted the distorted image to hone in on the image that was equally likely to be judged as matching their perceived face as the accurate image. When viewed upright or upside down, face width was overestimated and length underestimated, whereas perception was accurate for the on-side views. These results provide the first psychophysically robust measurements of how accurately healthy participants perceive the size of their face, revealing distortions of the implicit body representation independent of the conscious body image.

A pilot body image intervention programme for in-patients with eating disorders in an NHS setting

Background:

Body image distortion, a distressing problem that precipitates eating disorders, remains a struggle for patients after other symptoms are controlled. Despite a strong physical aspect there is little recognition of physiotherapy intervention. This study aims to assess the effect of a tailored physiotherapy intervention programme for patients with eating disorders in an NHS in-patient unit.

Methods:

The intervention programme, targeted at known, potentially modifiable factors relevant to body image distortion in 7 patients, used touch, massage, drawing exercises and listening skills. Patients received 8 to 38 sessions determined by length of stay on the unit. Self-drawings were completed at each session and a body shape questionnaire (BSQ-34) and a self-assessment silhouette scale in the first and last sessions.

Findings:

Self-drawings showed improved comparative proportions of body areas. Initial silhouette scores of more than 5 out of 10 reduced to less than five. There was a reduction in BSQ-34 questionnaire scores for all patients, and to less than half for 3.

Conclusions:

This pilot study suggests that a tailored programme based on principles of physiotherapy can help to improve body image perception and satisfaction. It draws attention to the potential of physiotherapy intervention programmes in the UK.

Body size estimation in early adolescence: factors associated with perceptual accuracy in a nonclinical sample

This study investigated body size estimation in Norwegian adolescents (aged 12-15; N=406) using a distorting photograph technique. The percentage of over- or underestimation was calculated for pictures of the subject, other persons and a neutral object. The Eating Disorders Inventory for Children (EDI-C) was also completed. Among adolescents at risk of eating problems, girls tended to overestimate their own body size while boys showed a pattern of underestimation, compared to a relatively accurate body perception for low-risk subjects. The groups did not differ in the perception of the neutral object. Important predictors of perceived body size included the size estimation of other children, preoccupation with weight and shape, self-esteem, and emotional instability. The results support the predictive value of body size estimation. Gender differences in judgement bias can be interpreted within present aesthetic ideals and their relation to self perception, body image, and eating problems in adolescence.

Drive for thinness and attention toward specific body parts in a nonclinical sample

OBJECTIVE

To examine the differences between participants scoring high versus low on a drive for thinness construct concerning their visual attention toward specific body parts. We hypothesized that participants scoring high on the drive for thinness subscale would show increased attention to body regions, which are important in the assessment of body weight and thinness like the waist, hips, legs, and arms.

METHOD

We examined eye-gaze behavior of a nonclinical sample of 51 male and female college students with an eye-tracking system as they were looking at pictures of young, attractive males and females. In addition, we used the Eating Disorder Inventory to measure drive for thinness.

RESULTS

Participants with increased scores on the drive for thinness subscale looked longer and more often to the waist, hips, legs, and arms as compared with low scorers. In addition, they showed decreased attention toward the head or face.

CONCLUSION

The results indicate that participants scoring high on drive for thinness show an attentional bias toward body regions that are associated with assessing changes in weight. However, they neglected the face, which is the most important source of social and affective information when looking at others.

Multitrait-multimethod investigation of a novel body image measurement technique

A multitrait-multimethod (MTMM) matrix was used to evaluate validity evidence for a digital image manipulation (DIM) body image measurement technique in young women. One hundred one young women completed the DIM procedure and the Thompson and Gray (1995) Contour Drawing Rating Scale to measure self-ideal discrepancy and size perception accuracy components of body image. Seven-day test-retest reliability was acceptable (R = .81-.95). Convergent validity for self-ideal discrepancy was higher (r = .74) than the corresponding heterotrait, monomethod coefficients (r = .46, r = .23) and heterotrait-heteromethod coefficients (r = .18, r = .12). However, the convergent validity coefficient for size perception accuracy was r = .12. The pattern of correlations in the MTMM matrix met the criteria of Campbell and Fiske (1959) for validity of these procedures to measure self-ideal discrepancy but not size perception accuracy. The DIM procedure addresses some of the criticisms associated with figure-rating scales, such as unrepresentativeness of the figures, scale coarseness, and restriction of range in responses. DIM, therefore, represents a realistic, valid alternative to figure-rating scales for measuring self-ideal discrepancy.

Changes in body image during cognitive-behavioral treatment in women with bulimia nervosa

The purposes of this study were: (1) to examine multidimensional aspects of body image of individuals with bulimia nervosa (BN) at pre-treatment, post-treatment, and at follow-up, compared to a group of participants without BN; and (2) to investigate whether measures of body image predicted outcome at post-treatment and follow-up. The clinical sample consisted of 109 females with BN who were enrolled in a 12-week cognitive-behavioral group treatment program. Participants were assessed at baseline, at the completion of treatment, and at 1- and 6-month follow-up visits. The 82 females who comprised the non-bulimic sample were assessed at comparable time intervals. At baseline, the participants with BN reported greater body dissatisfaction and overestimated body size to a significantly greater degree than the comparison group, and reported a significantly smaller ideal size relative to perceived size. Results at the end of treatment indicated significant improvement in self-reported attitudinal disturbance and size overestimation, with continued reductions at follow-up. Logistic regression analyses did not demonstrate a predictive relationship between body image measures at baseline and outcome at post-treatment or follow-up, or between post-treatment and follow-up. Implications for treatment include specifying the source of body image-related distress and enhancing treatment efforts for perceptual and attitudinal aspects of body image.

Body size estimation: testing a new mirror-based assessment method

OBJECTIVE

The aim of the current study was to compare a new ecologically valid method of body size estimation with an existing, commonly used method.

METHOD

The new method uses a "mirror-sized" image and measures perception rather than memory of body size. Fifty-five healthy women participated in the study.

RESULTS

Body size estimations with the new method were significantly larger than with the existing method (p <.001). This difference was specific to body size and was not seen for estimation of neutral images.

DISCUSSION

The results of the study show that different body size estimations are made with the new more ecologically valid method compared with the existing method. This finding has important implications for research into the factors influencing the perception of body size.

A new ecologically valid method to assess body size estimation and body size dissatisfaction

OBJECTIVE

The primary aim of the present study was to develop an ecologically valid method for assessing the perception of body size (as opposed to the memory of body size).

METHOD

Women with clinical eating disorders (N = 14) and no eating disorder (N = 24) estimated their actual and desired body size while looking in a mirror. Estimations were made using projected images that were the same height as the participants' reflections in the mirror.

RESULTS

This new method assessed the perception of body size under conditions that resembled the real-life situation of viewing oneself in a mirror. Participants with eating disorders significantly overestimated their body size relative to controls (p <.05) and tended to be more dissatisfied with their body size (p =.07).

DISCUSSION

It is argued that the new method assesses the perception of body size, is ecologically valid, and is the most clinically relevant of the methods developed to date.

Body size estimation in anorexia nervosa patients: the significance of overestimation

Using the video distortion method on a life-size screen, we have studied body size estimation in 100 female restricting anorexia nervosa patients. About half of the patients were accurate in estimating their own body dimensions and only 20% clearly showed overestimation. We then tested whether differences in accuracy of estimation were related to scores on the following questionnaires: Eating Disorder Inventory; Body Attitude Test; and Symptom Checklist (SCL-90). Overestimators reported a more negative body attitude and a more "neurotic profile" on the SCL-90. These differences might have both prognostic and therapeutic implications.

Body image in early-onset obese patients

In a group of early-onset-obesity obese patients eating behaviour, body image and psychological condition were assessed by the Eating Disorder Inventory, the Three Factor Eating Questionnaire, the Body Shape Questionnaire and the Body Attitude Questionnaire. These evaluations were carried out prior to and at long-term follow-up after biliopancreatic diversion when body weight had steadily fallen towards normal values. The aim was to establish the influence of actual body weight and shape over body image. A notable improvement in eating behaviour and overall psychological conditions was observed, while the parameters assessing body image remained substantially unchanged, indicating that early-onset-obesity postobese subjects, despite having obtained normal or nearly normal weight conditions, are still much more dissatisfied with their body weight and somatic morphology than never-obese subjects with very similar actual body weights.

Body image disturbances and their change with videofeedback in anorexia nervosa

Disturbance in the way the body is experienced is a diagnostic criterion for anorexia nervosa, and impedes recovery. A method relatively free of external prompts, to reduce the potential for experimentally induced biases, evaluated body image distortions (BID) in 18 patients with anorexia nervosa soon after admission to an inpatient unit, and 18 normal controls, before and after a videofeedback session. The BID were assessed in the affective and self/social domains by visual analogue scales in which the instructional set oriented subjects to (a) the sensation of fatness (Affective Response, AR), and (b) size compared with other young women (Comparative Size Response, CSR). The AR and CSR were significantly greater than normal in anorexia but decreased significantly with videofeedback, while values for controls were stable. The AR and CSR were only partially independent, indicating overlap of the domains. In anorexia only, the responses were related to two DSM-IV diagnostic criteria for anorexia, fear of gaining weight and health-weight concerns, as well as to drive for thinness and body dissatisfaction. Fear of gaining weight occupied a central position in determining the magnitudes of BID and the other measures, including anxiety and depression.