Nonvisual multisensory impairment of body perception in anorexia nervosa: a systematic review of neuropsychological studies

Background

Body image distortion is a central symptom of Anorexia Nervosa (AN). Even if corporeal awareness is multisensory majority of AN studies mainly investigated visual misperception. We systematically reviewed AN studies that have investigated different nonvisual sensory inputs using an integrative multisensory approach to body perception. We also discussed the findings in the light of AN neuroimaging evidence.

Methods

PubMed and PsycINFO were searched until March, 2014. To be included in the review, studies were mainly required to: investigate a sample of patients with current or past AN and a control group and use tasks that directly elicited one or more nonvisual sensory domains.

Results

Thirteen studies were included. They studied a total of 223 people with current or past AN and 273 control subjects. Overall, results show impairment in tactile and proprioceptive domains of body perception in AN patients. Interoception and multisensory integration have been poorly explored directly in AN patients. A limitation of this review is the relatively small amount of literature available.

Conclusions

Our results showed that AN patients had a multisensory impairment of body perception that goes beyond visual misperception and involves tactile and proprioceptive sensory components. Furthermore, impairment of tactile and proprioceptive components may be associated with parietal cortex alterations in AN patients. Interoception and multisensory integration have been weakly explored directly. Further research, using multisensory approaches as well as neuroimaging techniques, is needed to better define the complexity of body image distortion in AN.

Key Findings

The review suggests an altered capacity of AN patients in processing and integration of bodily signals: body parts are experienced as dissociated from their holistic and perceptive dimensions. Specifically, it is likely that not only perception but memory, and in particular sensorimotor/proprioceptive memory, probably shapes bodily experience in patients with AN.

[Development of a questionnaire for body weight associated anxiety in anorexia nervosa]

Anxiety plays a comprehensive role in the psychopathology of anorexic patients and the long-term course of the disorder. Despite the importance of the major symptoms: weight phobia, there has been no systematic documentation to date of therapeutically and prognostically meaningful weight-associated fears. Given the use of a preventative approach in the early diagnosis of specific anxiety symptoms. We developed a questionnaire (Anorexia Anxiety Scale, AAS) based on a survey of 372 girls attending different types of secondary schools and a sample of 26 former patients. The number of items was reduced from 32 to 8 by means of a factor analysis. Upon further validation, the questionnaire should then be applicable for use as a screening instrument.

Neuronal activity changes and body image distortion in anorexia nervosa

Body image distortion is a major and often persistent symptom in anorexia nervosa. During a functional imaging investigation we confronted female anorectic patients and healthy controls with their own digitally distorted body images using a computer-based video-technique. Our findings indicate activation of the attention network as well as of structures involved in visuo-spatial processing and self-reflection in both groups. Anorectic patients showed a greater activation in the prefrontal cortex (BA 9) and the inferior parietal lobule (BA 40), including the anterior intraparietal sulcus, than did controls. However, an analysis of the BOLD-response in the IPL area revealed that anorectic patients showed only a specific increase in activation to their own pictures than to others indicating different visuo-spatial processing, while controls did not differentiate.