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BackgroundBody 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.MethodsPubMed 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.ResultsThirteen 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.ConclusionsOur 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 FindingsThe 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.

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This paper systematically reviews the literature pertaining to the use of resting-state functional magnetic resonance imaging (rsfMRI) in anorexia nervosa (AN), classifying studies on the basis of different analysis approaches. We followed PRISMA guidelines. Fifteen papers were included, investigating a total of 294 participants with current or past AN and 285 controls. The studies used seed-based, whole-brain independent component analysis (ICA), network-of-interest ICA based and graph analysis approaches. The studies showed relatively consistent overlap in results, yet little overlap in their analytical approach and/or a-priori assumptions. Functional connectivity alterations were mainly found in the corticolimbic circuitry, involved in cognitive control and visual and homeostatic integration. Some overlapping findings were found in brain areas putatively important in AN, such as the insula. These results suggest altered functional connectivity in networks/areas linked to the main symptom domains of AN, such as impaired cognitive control and body image disturbances. These preliminary evidences suggest that more targeted treatments need to be developed that focus on these two symptom domains. Further studies with multi-approach analyses and longitudinal designs are needed to better understand the complexity of AN.