ارزیابی بصری از حجم مواد غذایی در بیماران مبتلا به بی اشتهایی عصبی

bjective The study compares visual evaluation of an amount of food and an amount of nonedible objects in patients affected by Anorexia Nervosa and control subjects. Method 59 anorexic subjects were asked to evaluate an amount of candies and plastic bricks shown to them. Their answers were compared to both the real number of objects and the parallel evaluations given by 56 control subjects. Results There were no significant differences in stimuli evaluation between patients affected by AN and control subjects. Both groups reported a significantly lower number of both candies and bricks in comparison to their real number. Discussion In an experimental condition not related with food intake there is the same under-evaluation of the amount of presented food and nonedible objects among patients affected by AN and Control Subjects. The clinical finding of overestimation of food intake among patients affected by AN seems not to be due to a perceptive bias.

In clinical experience patients affected by Anorexia Nervosa frequently claim to feel the uncomfortable impression not to be able to reliably evaluate the amount of served food, engaging the therapists in time consuming Socratic debates about their food intake. We tried to assess if subjects affected by AN are not really able to accurately describe the amount of food to which they are exposed and if there are differences in food dose evaluation among AN patients and control subjects. Moreover we compared the estimation of edible and nonedible stimuli of the same size and shape, to find out if the nature of the stimulus influences the estimation of its amount. To our knowledge no research testing food dose evaluation in patients affected by AN has ever been done. There are few studies about their perceptive abilities, however all of them focusing on the patients' body shape and weight. Epstein et al. (2001), Skrzypek and Wehmeier (2001) report that AN patients haven't got any perceptive biases: their body size evaluation is based on cognitive factors. These factors probably influence also their food evaluation: Overduin, Jansen, and Louwerse (1995) found Stroop Interference for food related words in anorexic subjects; Urdapilleta, Mirabel-Sarron, Meunier, and Richard (2005) report that among AN patients top-down processes in judging food play a dominating role. When asked to categorize aliments, they cluster them based on consequences of ingestion, (in terms of health, digestion and weight gain) rather than on visual characteristics or palatability, as control subjects would do. In light of these results we carried out the study in an experimental situation without any relation to food intake. This was done to minimize the influence of emotional factors.