Body perception and evaluation in anorexia nervosa

Body image disturbance is a prominent feature in anorexia nervosa (AN) and encompasses alterations across the different dimensions of body image, that is, perception, affect, cognition, and behaviour. There is a wealth of research regarding the subjective experience of body image disturbance and evidence for underlying neuronal alterations is beginning to emerge. The present project was designed to assess basic processes underlying body image disturbance with the help of psychophysiological measurement techniques and self-other discrimination tasks. In study 1, using a self-other discrimination task with distorted body images, we were able to demonstrate interactions between perceptual factors and cognitive bias which may sustain a distorted and negative body image in healthy women. Study 2 showed a discrepancy between explicit negative ratings for body shapes and implicit neutral affect towards the same images, as assessed with an affective startle-modulation paradigm, in healthy women and women with AN. These results suggest that automatic fear responses to fat-distorted self-body pictures, as well as implicit approach motivation towards thin body images, as reported in previous studies, are not present in all patients with AN. In study 3 a differential alteration of featural and configural visual processing of body images was detected in an event-related brain potentials (EEG-ERP) paradigm. Individuals with AN showed a lack of discrimination between self-body and self-object pictures between 105 and 160 ms after stimulus onset (P1 component, featural processing) and an enhanced processing of body relative to neutral object pictures between 160 and 225 ms after stimulus onset (N1 component, configural processing). This suggests alterations in the basic visual processing of body shapes in AN, which might be related to influences of top-down attentional modulation. Study 4 showed enhanced processing of cardiac visceral signals in the central nervous system (CNS) in individuals with AN, which might either be a marker of psychopathology, in particular anxiety, or an indication of clinical improvement. In summary, the present results do not support the view of a global perceptual deficit in AN, but demonstrate the complexity of body image alterations in AN. It appears mandatory to further investigate basic processes underlying body image disturbances in AN and in healthy women to arrive at a comprehensive understanding of their nature and to provide a theoretical basis for body image interventions. The importance of using specific assessment methods, such as indicators of body-related processing in the CNS, is highlighted.