Aberrant early visual neural activity and brain-behavior relationships in anorexia nervosa and body dysmorphic disorder

A hierarchy of visual processing deficits in body dysmorphic disorder: a conceptual review and empirical investigation

OBJECTIVE

Abnormal visual processing has been proposed as a mechanism underlying excessive focus on minor appearance flaws in body dysmorphic disorder (BDD). Existing BDD research has not differentiated the various stages of face processing (featural, first-order configural, holistic and second-order configural) that are required for higher-order processes such as emotion recognition. This study investigated a hierarchical visual processing model to examine the nature of abnormalities in face processing in BDD.

METHOD

Thirty BDD participants and 27 healthy controls completed the Navon task, a featural and configural face processing task and a facial emotion labelling task.

RESULTS

BDD participants performed similarly to controls when processing global and local non-face stimuli on the Navon task, when detecting subtle changes in the features and spacing of a target face, and when labelling emotional faces. However, BDD participants displayed poorer performance when viewing inverted faces, indicating difficulties in configural processing.

CONCLUSIONS

The findings only partially support prior work. However, synthesis of results with previous findings indicates that heterogenous task methodologies may contribute to inconsistent findings. Recommendations are provided regarding the task parameters that appear most sensitive to abnormalities in BDD.

Anosognosia in hoarding disorder is predicted by alterations in cognitive and inhibitory control

Insight impairment contributes significantly to morbidity in psychiatric disorders. The neurologic concept of anosognosia, reflecting deficits in metacognitive awareness of illness, is increasingly understood as relevant to psychopathology, but has been little explored in psychiatric disorders other than schizophrenia. We explored anosognosia as an aspect of insight impairment in n = 71 individuals with DSM-5 hoarding disorder. We used a standardized clutter severity measure to assess whether individuals with hoarding disorder underreport home clutter levels relative to independent examiners. We then explored whether underreporting, as a proxy for anosognosia, is predicted by clinical or neurocognitive behavioral measures. We found that individuals with hoarding disorder underreport their clutter, and that underreporting is predicted by objective severity of clutter. In an n = 53 subset of participants, we found that underreporting is predicted by altered performance on tests of cognitive control and inhibition, specifically Go/No-Go and Stroop tests. The relation of underreporting to objective clutter, the cardinal symptom of hoarding disorder, suggests that anosognosia may reflect core pathophysiology of the disorder. The neurocognitive predictors of clutter underreporting suggest that anosognosia in hoarding disorder shares a neural basis with metacognitive awareness deficits in other neuropsychiatric disorders and that executive anosognosia may be a transdiagnostic manifestation of psychopathology.

Neural and behavioral effects of modification of visual attention in body dysmorphic disorder

In individuals with body dysmorphic disorder (BDD), perceptual appearance distortions may be related to selective attention biases and aberrant visual scanning, contributing to imbalances in global vs. detailed visual processing. Treatments for the core symptom of perceptual distortions are underexplored in BDD; yet understanding their mechanistic effects on brain function is critical for rational treatment development. This study tested a behavioral strategy of visual-attention modification on visual system brain connectivity and eye behaviors. We acquired fMRI data in 37 unmedicated adults with BDD and 30 healthy controls. Participants viewed their faces naturalistically (naturalistic viewing), and holding their gaze on the image center (modulated viewing), monitored with an eye-tracking camera. We analyzed dynamic effective connectivity and visual fixation duration. Modulated viewing resulted in longer mean visual fixation duration compared to during naturalistic viewing, across groups. Further, modulated viewing resulted in stronger connectivity from occipital to parietal dorsal visual stream regions, also evident during the subsequent naturalistic viewing, compared with the initial naturalistic viewing, in BDD. Longer fixation duration was associated with a trend for stronger connectivity during modulated viewing. Those with more severe BDD symptoms had weaker dorsal visual stream connectivity during naturalistic viewing, and those with more negative appearance evaluations had weaker connectivity during modulated viewing. In sum, holding a constant gaze on a non-concerning area of one's face may confer increased communication in the occipital/parietal dorsal visual stream, facilitating global/holistic visual processing. This effect shows persistence during subsequent naturalistic viewing. Results have implications for perceptual retraining treatment designs.

Dynamic Effective Connectivity Patterns During Rapid Face Stimuli Presentation in Body Dysmorphic Disorder

In individuals with body dysmorphic disorder (BDD), perceptual appearance distortions may be related to imbalances in global vs. local visual processing. Understanding the mechanistic brain effects of potential interventions is crucial for rational treatment development. The dorsal visual stream (DVS) is tuned to rapid image presentation, facilitating global/holistic processing, whereas the ventral visual stream (VVS), responsible for local/detailed processing, reduces activation magnitude with shorter stimulus duration. This study tested a strategy of rapid, short-duration face presentation on visual system connectivity. Thirty-eight unmedicated adults with BDD and 29 healthy controls viewed photographs of their faces for short (125 ms, 250 ms, 500 ms) and long (3000 ms) durations during fMRI scan. Dynamic effective connectivity in DVS and VVS was analyzed. BDD individuals exhibited weaker connectivity from occipital to parietal DVS areas than controls for all stimuli durations. Short compared with long viewing durations (125 ms vs. 3,000 ms and 500 ms vs. 3,000 ms) resulted in significantly weaker VVS connectivity from calcarine cortex to inferior occipital gyri in controls; however, there was only a trend for similar results in BDD. The DVS to VVS ratio, representing a balance between global and local processing, incrementally increased with shorter viewing durations in BDD, although it was not statistically significant. In sum, visual systems in those with BDD are not as responsive as in controls to rapid face presentation. Whether rapid face presentation could reduce connectivity in visual systems responsible for local/detailed processing in BDD may necessitate different parameters or strategies. These results provide mechanistic insights for perceptual retraining treatment designs.

Effects of visual attention modulation on dynamic functional connectivity during own-face viewing in body dysmorphic disorder

Body dysmorphic disorder (BDD) is characterized by preoccupations with misperceptions of one's physical appearance. Previous neuroimaging studies in BDD have yet to examine dynamic functional connectivity (FC) patterns between brain areas, necessary to capture changes in activity in response to stimuli and task conditions. We used Leading Eigenvector Dynamics Analysis to examine whole-brain dynamic FC from fMRI data during an own-face viewing task in 29 unmedicated adults with BDD with facial concerns and 30 healthy controls. The task involved two parts: (1) unconstrained, naturalistic viewing and (2) holding visual attention in the center of the image, to reduce scanning and fixation on perceived facial flaws. An FC state consisting of bilateral medial orbitofrontal cortex regions occurred significantly less often during the visual attention condition and afterward during the unconstrained face viewing in BDD participants, compared to the first unconstrained face viewing, a pattern that differed from controls. Moreover, the probability of this state during the second unconstrained face viewing was associated with severity of obsessions and compulsions and degree of poor insight in BDD, suggesting its clinical significance. These findings have implications for understanding the pathophysiology of own-face viewing in BDD and how it is affected by modification of viewing patterns, which may have implications for novel perceptual retraining treatment designs.

Brain activation and connectivity in anorexia nervosa and body dysmorphic disorder when viewing bodies: relationships to clinical symptoms and perception of appearance

Anorexia nervosa (AN) and body dysmorphic disorder (BDD) are characterized by distorted perception of appearance, yet no studies have directly compared the neurobiology associated with body perception. We compared AN and BDD in brain activation and connectivity in relevant networks when viewing images of others' bodies and tested their relationships with clinical symptoms and subjective appearance evaluations. We acquired fMRI data from 64 unmedicated females (20 weight-restored AN, 23 BDD, 21 controls) during a matching task using unaltered or spatial-frequency filtered photos of others' bodies. Using general linear model and independent components analyses we compared brain activation and connectivity in visual, striatal, and parietal networks and performed univariate and partial least squares multivariate analyses to investigate relationships with clinical symptoms and appearance evaluations. AN and BDD showed partially overlapping patterns of hyperconnectivity in the dorsal visual network and hypoconnectivity in parietal network compared with controls. BDD, but not AN, demonstrated hypoactivity in dorsal visual and parietal networks compared to controls. Further, there were significant activity and connectivity differences between AN and BDD in both networks. In both groups, activity and/or connectivity were associated with symptom severity and appearance ratings of others' bodies. Thus, AN and BDD demonstrate both distinct and partially-overlapping aberrant neural phenotypes involved in body processing and visually encoding global features. Nevertheless, in each disorder, aberrant activity and connectivity show relationships to clinically relevant symptoms and subjective perception. These results have implications for understanding distinct and shared pathophysiology underlying perceptual distortions of appearance and may inform future novel treatment strategies.

Visual mapping of body image disturbance in anorexia nervosa reveals objective markers of illness severity

Body image disturbance (BID) is a core feature of eating disorders, for which there are few objective markers. We examined the feasibility of a novel digital tool, "Somatomap", to index BID related to anorexia nervosa (AN) severity. Fifty-five AN inpatients and 55 healthy comparisons (HC) outlined their body concerns on a 2-Dimensional avatar. Next, they indicated sizes/shapes of body parts for their current and ideal body using sliders on a 3-Dimensional avatar. Physical measurements of corresponding body parts, in cm, were collected for reference. We evaluated regional differences in BID using proportional z-scores to generate statistical body maps, and multivariate analysis of covariance to assess perceptual discrepancies for current body, ideal body, and body dissatisfaction. The AN group demonstrated greater regional perceptual inaccuracy for their current body than HC, greater discrepancies between their current and ideal body, and higher body dissatisfaction than HCs. AN body concerns localized disproportionately to the chest and lower abdomen. The number of body concerns and perceptual inaccuracy for individual body parts was strongly associated with Eating Disorder Examination Questionnaire (Global EDE-Q) scores across both groups. Somatomap demonstrated feasibility to capture multidimensional aspects of BID. Several implicit measures were significantly associated with illness severity, suggesting potential utility for identifying objective BID markers.

Is poor global processing a transdiagnostic feature of Body Dysmorphic Disorder and Anorexia Nervosa? A meta-analysis

Body dysmorphic disorder (BDD) and anorexia nervosa (AN) are characterised by body image disturbance. It has been suggested that poor global integration in visual processing may underlie distorted body image, but empirical studies have yielded mixed results. The current study involved two meta-analyses aimed at examining the extent to which poor global processing is evident in BDD and AN. Studies were identified through a systematic literature search up to October 2020. The BDD search yielded 16 studies and the AN search yielded 18 studies. Random-effect models demonstrated a small pooled effect size for BDD (g = -0.44, 95 % CI -0.70, -0.17, p < 0.001) and a moderate pooled effect size for AN (g = -0.63, 95 % CI -0.77, -0.49, p <  .001), with no evidence of significant publication bias for either. The results provide evidence that poor global processing is a transdiagnostic feature of both BDD and AN, although effects may be more pronounced in AN. Our findings highlight the possibility that interventions aimed at promoting global visual processing could prove beneficial in disorders characterised by distorted body image.

Increased early motivational response to food in adolescent anorexia nervosa revealed by magnetoencephalography

BACKGROUND

It remains unclear to what extent reduced nutritional intake in anorexia nervosa (AN) is a consequence of a reduced motivational response to food. Although self-reports typically suggest AN patients have a reduced appetitive response, behavioral and neurophysiological measures have revealed evidence for both increased and reduced attentional biases towards food stimuli. The mechanisms influencing food perception in AN, might be clarified using time-sensitive magnetoencephalography (MEG) to differentiate the early (more automatic processing) stages from the late (more controlled) stages.

METHODS

MEG was recorded in 22 partially weight-restored adolescent AN patients and 29 age- and gender-matched healthy control (HC) participants during a rapid serial visual presentation paradigm using 100 high-calorie food, 100 low-calorie food, and 100 non-food pictures. Neural sources of event-related fields were estimated using the L2-Minimum-Norm method and analyzed in early (50-300 ms) and late (350-500 ms) time intervals.

RESULTS

AN patients rated high-calorie food as less palatable and reported overall less food craving than HC participants. Nevertheless, in response to food pictures AN patients showed relative increased neural activity in the left occipito-temporal and inferior frontal regions in the early time interval. No group differences occurred in the late time interval.

CONCLUSIONS

MEG results speak against an overall reduced motivational response to food in AN. Instead, relative increased early food processing in the visual cortex suggests greater motivated attention. A greater appetitive response to food might be an adaptive mechanism in a state of undernourishment. Yet, this relative increased food processing in AN was no longer present later, arguably reflecting rapid downregulation.

Early auditory-evoked potentials in body dysmorphic disorder: An ERP/sLORETA study

Body dysmorphic disorder (BDD) is characterized by excessive preoccupation with imagined or slight physical defects in appearance. BDD is associated with cognitive impairments (attention, visual processing). Our study aims to evaluate the early neural responses (N100, P200) to prepulse inhibition (PPI) and prepulse facilitation (PPF), to investigate attentional processing of BDD in the auditory domain. Fifty-five adults took part: 30 BDD patients and 25 healthy controls. We compared their brain responses to PPI and PPF by analyzing global field power (GFP), event-related potentials (ERPs) and their respective sources. BDD exhibited reduced N100 amplitudes compared to healthy controls in response to the startle tone elicited by both PPI and PPF, potentially suggesting impaired allocation of attention. Interestingly, the lower the GFP at the N100, the higher the BDD severity. Source reconstruction analysis showed reduced activation for BDD during the N100 time window in PPI. Scalp responses and source activations in PPI were decreased overall compared to PPF, confirming the gating effect of PPI. We provided evidence that the N100 may serve as an electrophysiological marker of BDD, predicting its severity. Our study demonstrated the potential of using ERPs combined with behavioural PPI and PPF protocols to advance our understanding of BDD pathophysiology.

Study protocol of comprehensive risk evaluation for anorexia nervosa in twins (CREAT): a study of discordant monozygotic twins with anorexia nervosa

BACKGROUND

Anorexia nervosa (AN) is a severe disorder, for which genetic evidence suggests psychiatric as well as metabolic origins. AN has high somatic and psychiatric comorbidities, broad impact on quality of life, and elevated mortality. Risk factor studies of AN have focused on differences between acutely ill and recovered individuals. Such comparisons often yield ambiguous conclusions, as alterations could reflect different effects depending on the comparison. Whereas differences found in acutely ill patients could reflect state effects that are due to acute starvation or acute disease-specific factors, they could also reflect underlying traits. Observations in recovered individuals could reflect either an underlying trait or a "scar" due to lasting effects of sustained undernutrition and illness. The co-twin control design (i.e., monozygotic [MZ] twins who are discordant for AN and MZ concordant control twin pairs) affords at least partial disambiguation of these effects.

METHODS

Comprehensive Risk Evaluation for Anorexia nervosa in Twins (CREAT) will be the largest and most comprehensive investigation of twins who are discordant for AN to date. CREAT utilizes a co-twin control design that includes endocrinological, neurocognitive, neuroimaging, genomic, and multi-omic approaches coupled with an experimental component that explores the impact of an overnight fast on most measured parameters.

DISCUSSION

The multimodal longitudinal twin assessment of the CREAT study will help to disambiguate state, trait, and "scar" effects, and thereby enable a deeper understanding of the contribution of genetics, epigenetics, cognitive functions, brain structure and function, metabolism, endocrinology, microbiology, and immunology to the etiology and maintenance of AN.

Multimodal neuroimaging in anorexia nervosa

Anorexia nervosa (AN) is a severe and complex psychiatric disorder characterized by intense fear about weight gain and finalized to food-related control behaviors. Growing interest has been demonstrated about neurobiological processes subtend to AN physiopathology. The present review aimed to collect neurostructural and neurofunctional available data from 2010 to 2019. Results have been organized according to the neuroimaging technique employed, also including a specific section on electroencephalographic results, mostly neglected in previous reviews. Diffuse cerebral vulnerability has been demonstrated and the contribution of several structures has been identified. Insula, cingulate cortex, parietal and frontal areas are primarily involved both by structural and functional perspectives. Moreover, consistent alterations in white matter integrity and brain electrical activity have been reported. Neuroimaging findings give a substantial contribution to AN pathophysiological description, also in order to understand altered but reversible processes in the passage from acute illness phase to disorder's remission, useful also for defining therapy.

Neural Correlates of Own- and Other-Face Perception in Body Dysmorphic Disorder

BACKGROUND

Body dysmorphic disorder (BDD) is characterized by an excessive preoccupation with one or more perceived flaws in one's own appearance. Previous studies provided evidence for deficits in configural and holistic processing in BDD. Preliminary evidence suggests abnormalities at an early stage of visual processing. The present study is the first examining early neurocognitive perception of the own face in BDD by using electroencephalography (EEG). We investigated the face inversion effect, in which inverted (upside-down) faces are disproportionately poorly processed compared to upright faces. This effect reflects a disruption of configural and holistic processing, and in consequence a preponderance of featural face processing.

METHODS

We recorded face-sensitive event-related potentials (ERPs) in 16 BDD patients and 16 healthy controls, all unmedicated. Participants viewed upright and inverted (upside-down) images of their own face and an unfamiliar other face, each in two facial emotional expressions (neutral vs. smiling). We calculated the early ERP components P100, N170, P200, N250, and the late positive component (LPC), and compared amplitudes among both groups.

RESULTS

In the early P100, no face inversion effects were found in both groups. In the N170, both groups exhibited the common face inversion effects, with significantly larger N170 amplitudes for inverted than upright faces. In the P200, both groups exhibited larger inversion effects to other (relative to own) faces, with larger P200 amplitudes for other upright than inverted faces. In the N250, no significant group differences were found in face processing. In the LPC, both groups exhibited larger inversion effects to other (relative to own) faces, with larger LPC amplitudes for other inverted than upright faces. These overall patterns appeared to be comparable for both groups. Smaller inversion effects to own (relative to other) faces were observed in none of these components in BDD, relative to controls.

CONCLUSIONS

The findings suggest no evidence for abnormalities at all levels of early face processing in our observed sample of BDD patients. Further research should investigate the neural substrates underlying BDD symptomatology.

A Novel Mobile Tool (Somatomap) to Assess Body Image Perception Pilot Tested With Fashion Models and Nonmodels: Cross-Sectional Study

BACKGROUND

Distorted perception of one's body and appearance, in general, is a core feature of several psychiatric disorders including anorexia nervosa and body dysmorphic disorder and is operative to varying degrees in nonclinical populations. Yet, body image perception is challenging to assess, given its subjective nature and variety of manifestations. The currently available methods have several limitations including restricted ability to assess perceptions of specific body areas. To address these limitations, we created Somatomap, a mobile tool that enables individuals to visually represent their perception of body-part sizes and shapes as well as areas of body concerns and record the emotional valence of concerns.

OBJECTIVE

This study aimed to develop and pilot test the feasibility of a novel mobile tool for assessing 2D and 3D body image perception.

METHODS

We developed a mobile 2D tool consisting of a manikin figure on which participants outline areas of body concern and indicate the nature, intensity, and emotional valence of the concern. We also developed a mobile 3D tool consisting of an avatar on which participants select individual body parts and use sliders to manipulate their size and shape. The tool was pilot tested on 103 women: 65 professional fashion models, a group disproportionately exposed to their own visual appearance, and 38 nonmodels from the general population. Acceptability was assessed via a usability rating scale. To identify areas of body concern in 2D, topographical body maps were created by combining assessments across individuals. Statistical body maps of group differences in body concern were subsequently calculated using the formula for proportional z-score. To identify areas of body concern in 3D, participants' subjective estimates from the 3D avatar were compared to corresponding measurements of their actual body parts. Discrepancy scores were calculated based on the difference between the perceived and actual body parts and evaluated using multivariate analysis of covariance.

RESULTS

Statistical body maps revealed different areas of body concern between models (more frequently about thighs and buttocks) and nonmodels (more frequently about abdomen/waist). Models were more accurate at estimating their overall body size, whereas nonmodels tended to underestimate the size of individual body parts, showing greater discrepancy scores for bust, biceps, waist, hips, and calves but not shoulders and thighs. Models and nonmodels reported high ease-of-use scores (8.4/10 and 8.5/10, respectively), and the resulting 3D avatar closely resembled their actual body (72.7% and 75.2%, respectively).

CONCLUSIONS

These pilot results suggest that Somatomap is feasible to use and offers new opportunities for assessment of body image perception in mobile settings. Although further testing is needed to determine the applicability of this approach to other populations, Somatomap provides unique insight into how humans perceive and represent the visual characteristics of their body.

Intranasal oxytocin alters amygdala-temporal resting-state functional connectivity in body dysmorphic disorder: A double-blind placebo-controlled randomized trial

The aetiology of body dysmorphic disorder (BDD) is poorly understood. Recent evidence from functional brain imaging studies suggests that BDD is associated with aberrant task-based functional connectivity and that intranasal oxytocin (OXT) may improve network connectivity in BDD patients. Thus, the aim of this study was to investigate the effect of intranasal OXT on amygdala resting-state functional connectivity (rsFC) in BDD. In a randomized, double-blind, cross-over design, 19 BDD participants and 17 demographically matched healthy control participants received intranasal OXT (24 IU) or placebo prior to resting-state functional magnetic resonance imaging. The left and right amygdala were seeded as regions of interest, and temporal correlations between the amygdalae and all other voxels comprising cortical and subcortical grey matter were investigated. Compared to healthy controls, BDD patients showed greater baseline (placebo) rsFC between the left amygdala and two clusters within the left temporal lobe and one cluster within the superior frontal gyrus which was reversed following OXT administration. The control group also showed significantly greater rsFC between the left amygdala and anterior prefrontal cortex in the OXT session compared to placebo. Whilst preliminary, these findings suggest that BDD patients exhibit abnormal amygdala-temporal connectivity at rest, and OXT might have a role in changing this functional relationship.

Differentiating weight-restored anorexia nervosa and body dysmorphic disorder using neuroimaging and psychometric markers

Anorexia nervosa (AN) and body dysmorphic disorder (BDD) are potentially life-threatening conditions whose partially overlapping phenomenology—distorted perception of appearance, obsessions/compulsions, and limited insight—can make diagnostic distinction difficult in some cases. Accurate diagnosis is crucial, as the effective treatments for AN and BDD differ. To improve diagnostic accuracy and clarify the contributions of each of the multiple underlying factors, we developed a two-stage machine learning model that uses multimodal, neurobiology-based, and symptom-based quantitative data as features: task-based functional magnetic resonance imaging data using body visual stimuli, graph theory metrics of white matter connectivity from diffusor tensor imaging, and anxiety, depression, and insight psychometric scores. In a sample of unmedicated adults with BDD (n = 29), unmedicated adults with weight-restored AN (n = 24), and healthy controls (n = 31), the resulting model labeled individuals with an accuracy of 76%, significantly better than the chance accuracy of 35% (p^<10‑4). In the multivariate model, reduced white matter global efficiency and better insight were associated more with AN than with BDD. These results improve our understanding of the relative contributions of the neurobiological characteristics and symptoms of these disorders. Moreover, this approach has the potential to aid clinicians in diagnosis, thereby leading to more tailored therapy.

Direct comparisons of anorexia nervosa and body dysmorphic disorder: A systematic review

Anorexia nervosa (AN) and body dysmorphic disorder (BDD) are serious psychiatric conditions, both of which are associated with a disturbance of body image. The aim of this paper was to review those studies that have directly compared groups of individuals with AN and BDD, to determine similarities and differences in presentation between the two conditions. The literature was searched to September 2018, and studies were included if they were English language, empirical research papers published in peer-reviewed journals, specifically comparing AN and BDD patients. Fifteen relevant studies were identified. The results suggested that individuals with AN and BDD share a number of similarities, including their degree of body dissatisfaction. Differences between the conditions included primary concerns with body shape and weight in AN, and much more diffuse concerns (but predominantly the face) in BDD. The small number of studies, along with the limited replication of results emphasises the need for greater research in this area. However, the studies undertaken to date highlight the high degree of overlap between AN and BDD and suggests that the conditions may represent similar body image disorders. This has implications for the nosological status of AN and BDD.

Visual training program for body dysmorphic disorder: protocol for a novel intervention pilot and feasibility trial

Background

Body dysmorphic disorder (BDD) is a characterised by perceived defects or flaws in appearance which are associated with distressing thoughts, repetitive or obsessive behaviours, and significant impairment in social and occupational functioning. A core feature of BDD involves abnormalities of visual processing, although this is not typically a focus of psychological and psychiatric treatments. While current treatments generally show moderate effectiveness in the short-term, those with BDD can have high relapse rates, as they still 'see' their flaws or defects. The current research trials a visual training program designed to remediate visual abnormalities and reduce symptom severity of BDD.

Methods

This is a single-group open-label pilot study assessing the feasibility and potential efficacy of a 10-week visual training program. This pilot trial will be conducted at Swinburne University of Technology, Melbourne, Australia, and will recruit up to 20 participants diagnosed with BDD. These participants will complete pre- and post-assessments and a 10-week visual training program encompassing three phases of basic visual processing, face and emotion recognition, and self-perception. The primary outcomes focus on feasibility and acceptability of the intervention, with secondary outcomes exploring clinical outcomes related to symptom severity, quality of life and eye movements.

Discussion

This pilot trial will translate the empirical findings of abnormalities in visual processing among those diagnosed with BDD, to an innovative treatment method across a range of visual processing levels. This trial will assess the feasibility and potential efficacy of such a visual training program, paving the way for further research including a future definitive randomised control trial.

Trial registration

Australian New Zealand Clinical Trial Registry, ACTRN 12618000274279, Registered 22nd February 2018.

The relationship between body dysmorphic disorder and obsessive-compulsive disorder: A systematic review of direct comparative studies

OBJECTIVE

Current nosology conceptualises body dysmorphic disorder as being related to obsessive-compulsive disorder, but the direct evidence to support this conceptualisation is mixed. In this systematic review, we aimed to provide an integrated overview of research that has directly compared body dysmorphic disorder and obsessive-compulsive disorder.

METHOD

The PubMed database was searched for empirical studies which had directly compared body dysmorphic disorder and obsessive-compulsive disorder groups across any subject matter. Of 379 records, 31 met inclusion criteria and were reviewed.

RESULTS

Evidence of similarities between body dysmorphic disorder and obsessive-compulsive disorder was identified for broad illness features, including age of onset, illness course, symptom severity and level of functional impairment, as well as high perfectionism and high fear of negative evaluation. However, insight was clearly worse in body dysmorphic disorder than obsessive-compulsive disorder, and preliminary data also suggested unique visual processing features, impaired facial affect recognition, increased social anxiety severity and overall greater social-affective dysregulation in body dysmorphic disorder relative to obsessive-compulsive disorder.

CONCLUSION

Limitations included a restricted number of studies overall, an absence of studies comparing biological parameters (e.g. neuroimaging), and the frequent inclusion of participants with comorbid body dysmorphic disorder and obsessive-compulsive disorder. Risks of interpreting common features as indications of shared underlying mechanisms are explored, and evidence of differences between the disorders are placed in the context of broader research findings. Overall, this review suggests that the current nosological status of body dysmorphic disorder is somewhat tenuous and requires further investigation, with particular focus on dimensional, biological and aetiological elements.

A systematic review and meta-analysis of cognitive processing deficits associated with body dysmorphic disorder

This systematic review and meta-analysis examined the evidence supporting the association between body dysmorphic disorder (BDD) symptomology and four types of cognitive processing abnormalities: local processing, selective attention, interpretive biases, and memory deficits. Twenty-three studies met inclusion requirements that examined differences in performance on cognitive tasks between BDD and control groups across the four categories. Multilevel modelling was used to calculate an overall effect size for each cognitive category. BDD and control groups differed significantly on measures of selective attention (g = 0.60, 95% CI = 0.26: 0.93), interpretive biases (g = 0.30, 95% CI = . 07: 0.54), and memory deficits (g=.56, 95% CI = 0.26: 0.87). Differences between the BDD and control groups on measures of local processing did not reach significance. These findings support the hypothesis that people with BDD may selectively attend to perceived threats or to disorder-related stimuli, misinterpret ambiguous stimuli as threatening, overvalue the importance of attractiveness, and have inaccurate coding and recall for facial or bodily stimuli. Recommendations for future research of these specific cognitive deficits in BDD include introducing the use of Modified Dot Probe Paradigms and new treatment targets that can be used as adjuncts to current treatment modalities.

Early visual ERPs show stable body-sensitive patterns over a 4-week test period

Event-related potential (ERP) studies feature among the most cited papers in the field of body representation, with recent research highlighting the potential of ERPs as neuropsychiatric biomarkers. Despite this, investigation into how reliable early visual ERPs and body-sensitive effects are over time has been overlooked. This study therefore aimed to assess the stability of early body-sensitive effects and visual P1, N1 and VPP responses. Participants were asked to identify pictures of their own bodies, other bodies and houses during an EEG test session that was completed at the same time, once a week, for four consecutive weeks. Results showed that amplitude and latency of early visual components and their associated body-sensitive effects were stable over the 4-week period. Furthermore, correlational analyses revealed that VPP component amplitude might be more reliable than VPP latency and specific electrode sites might be more robust indicators of body-sensitive cortical activity than others. These findings suggest that visual P1, N1 and VPP responses, alongside body-sensitive N1/VPP effects, are robust indications of neuronal activity. We conclude that these components are eligible to be considered as electrophysiological biomarkers relevant to body representation.

A systematic review of visual processing and associated treatments in body dysmorphic disorder

OBJECTIVE

Recent advances in body dysmorphic disorder (BDD) have explored abnormal visual processing, yet it is unclear how this relates to treatment. The aim of this study was to summarize our current understanding of visual processing in BDD and review associated treatments.

METHOD

The literature was collected through PsycInfo and PubMed. Visual processing articles were included if written in English after 1970, had a specific BDD group compared to healthy controls and were not case studies. Due to the lack of research regarding treatments associated with visual processing, case studies were included.

RESULTS

A number of visual processing abnormalities are present in BDD, including face recognition, emotion identification, aesthetics, object recognition and gestalt processing. Differences to healthy controls include a dominance of detailed local processing over global processing and associated changes in brain activation in visual regions. Perceptual mirror retraining and some forms of self-exposure have demonstrated improved treatment outcomes, but have not been examined in isolation from broader treatments.

CONCLUSION

Despite these abnormalities in perception, particularly concerning face and emotion recognition, few BDD treatments attempt to specifically remediate this. The development of a novel visual training programme which addresses these widespread abnormalities may provide an effective treatment modality.

Appearance evaluation of others' faces and bodies in anorexia nervosa and body dysmorphic disorder

OBJECTIVE

Individuals with anorexia nervosa (AN) and body dysmorphic disorder (BDD) exhibit distorted perception and negative evaluations of their own appearance; however, little is known about how they perceive others' appearance, and whether or not the conditions share perceptual distortions.

METHOD

Thirty participants with BDD, 22 with AN, now weight-restored, and 39 healthy comparison participants (HC) rated photographs of others' faces and bodies on attractiveness, how overweight or underweight they were, and how much photographs triggered thoughts of their own appearance. We compared responses among groups by stimulus type and by level-of-detail (spatial frequency).

RESULTS

Compared to HCs, AN and BDD had lower attractiveness ratings for others' bodies and faces for high-detail and low-detail images, rated bodies as more overweight, and were more triggered to think of their own appearance for faces and bodies. In AN, symptom severity was associated with greater triggering of thoughts of own appearance and higher endorsement of overweight ratings for bodies. In BDD, symptom severity was associated with greater triggering of thoughts of own appearance for bodies and higher overweight ratings for low-detail images. BDD was more triggered to think of own facial appearance than AN.

DISCUSSION

AN and BDD show similar behavioral phenotypes of negative appearance evaluations for others' faces and bodies, and have thoughts of their own appearance triggered even for images outside of their primary appearance concerns, suggesting a more complex cross-disorder body-image phenotype than previously assumed. Future treatment strategies may benefit from addressing how these individuals evaluate others in addition to themselves. © 2016 Wiley Periodicals, Inc.(Int J Eat Disord 2017; 50:127-138).

Brain connectome modularity in weight-restored anorexia nervosa and body dysmorphic disorder

BACKGROUND

Anorexia nervosa (AN) and body dysmorphic disorder (BDD) frequently co-occur, and have several overlapping phenomenological features. Little is known about their shared neurobiology. The aim of the study was to compare modular organization of brain structural connectivity.

METHOD

We acquired diffusion-weighted magnetic resonance imaging data on unmedicated individuals with BDD (n = 29), weight-restored AN (n = 24) and healthy controls (HC) (n = 31). We constructed connectivity matrices using whole-brain white matter tractography, and compared modular structures across groups.

RESULTS

AN showed abnormal modularity involving frontal, basal ganglia and posterior cingulate nodes. There was a trend in BDD for similar abnormalities, but no significant differences compared with AN. In AN, poor insight correlated with longer path length in right caudal anterior cingulate and right posterior cingulate.

CONCLUSIONS

Abnormal network organization patterns in AN, partially shared with BDD, may have implications for understanding integration between reward and habit/ritual formation, as well as conflict monitoring/error detection.

Local and global visual processing and eating disorder traits: An event-related potential study

Recent studies have suggested that individuals with eating disorders show a stronger local processing bias and/or a weaker global bias in visual processing than typical individuals. In this study, healthy participants with varying scores on the Eating Disorder Examination Questionnaire (EDE-Q) performed the Navon task, a standard task of local and global visual processing, whilst electrophysiological measures were recorded. Global stimuli were presented that were made up of many local parts, and the information between levels was either compatible or incompatible. Participants were instructed to report the identity of either a global or a local target shape, while ignoring the other level. Higher EDE-Q scores were associated with enhanced amplitude of the P3 component during local visual processing, as well as greater P1 amplitude during local incompatible trials. These findings support the claim that eating disorders are associated with differences in local and global visual processing.