Visuo-Haptic information processing in patients suffering of anorexia nervosa

Introduction Several studies recently investigated how Anorexia Nervosa patients (ANp) process multimodal information. Longo (2015) hypothesized that ANp might be less reliant on visual perception of bodies than healthy controls (HC). Case et al. showed that processing of multimodal information might be disrupted in ANp. Literature lacks of studies that measure precisely and compare directly the contributions of each sensory input. Objective To investigate the integration of visual and haptic inputs in ANp compared with HC and measure the weight of each input. Method We used a visuo-haptic integration task with a setup adapted from Gori et al. (2008) to measure each sensory input's when judging the size of a cube according to Maximum Likelihood Estimation theory which describes the optimal multimodal integration behaviour (Ernst and Banks, 2002). Fifteen ANp and 16 HCs were recruited. Results Regardless the group, we found considerable individual variability about the integration processes; moreover, many participants did not integrate optimally. Correlation analysis suggested that ANp rely less on visual information then HC. Conclusions Despite using a setup previously validated with children, the observation that many HC did not integrate optimally is not in line with the results of previous studies, making it difficult the comparison with the AN group. The setup might not be adapted to adults and it needs to be improved. Our study shows for the first time how it might be possible to measure and compare directly the contribution of two different sensory modalities. This could provide precious information to deeply investigate the pathology.