The perception of affective touch in anorexia nervosa

Abstract

Anorexia nervosa (AN) is a disorder characterized by restricted eating, fears of gaining weight, and body image distortions. The etiology remains unknown; however impairments in social cognition and reward circuits contribute to the onset and maintenance of the disorder. One possibility is that AN is associated with reduced perceived pleasantness during social interactions. We therefore examined the perception of interpersonal, 'affective touch' and its social modulation in AN. We measured the perceived pleasantness of light, dynamic stroking touches applied to the forearm of 25 AN patients and 30 healthy controls using C Tactile (CT) afferents-optimal (3cm/s) and non-optimal (18cm/s) velocities, while simultaneously displaying images of faces showing rejecting, neutral and accepting expressions. CT-optimal touch, but not CT non-optimal touch, elicited significantly lower pleasantness ratings in AN patients compared with healthy controls. Pleasantness ratings were modulated by facial expressions in both groups in a similar fashion; namely, presenting socially accepting faces increased the perception of touch pleasantness more than neutral and rejecting faces. Our findings suggest that individuals with AN have a disordered, CT-based affective touch system. This impairment may be linked to their weakened interoceptive perception and distorted body representation.

The relation between human hair follicle density and touch perception

“…However, in these patients the potentially higher density of C-tactile afferents does not increase the pleasantness ratings. On the contrary, the ratings are decreased compared to normal participants 21 .…”

“…In our sample of healthy people, it is very likely that such a critical amount would be conserved in all participants. On the other hand, disturbances in affective touch perception have been found in patients suffering from anorexia nervosa 21 . These patients have a very low body volume and, following the argument that all hair follicles are formed in utero, should have more densely packed hair follicles and thereby also higher density of C-tactile afferents.…”

“…In a group of rare patients suffering from a significant reduction of thin nerve fibers, including C-tactile fibers, ratings of perceived pleasantness were significantly reduced compared to healthy controls 18 . Other clinical disorders where altered C-tactile processing has been found include for example autism 19, 20 and anorexia nervosa 21 .…”

Psychometric Evaluation and Norms for the Multidimensional Assessment of Interoceptive Awareness (MAIA) in a Clinical Eating Disorders Sample

“…Anorexia nervosa (AN) is associated with self‐reported sensory hyper‐responsivity, whereas bulimia nervosa (BN) is associated with sensory hypo‐responsivity (Brand‐Gothelf et al, ). Although individuals with AN are better able to detect their heartbeat and breathing sensations pre‐meal compared with healthy controls (Khalsa et al, ), they experience difficulty distinguishing actual from anticipated interoceptive signals, such as feelings of fullness (Perez, Coley, Crandall, Di Lorenzo, & Bravender, ), touch (Crucianelli, Cardi, Treasure, Jenkinson, & Fotopoulou, ), and pain (de Zwaan, Biener, Bach, Wiesnagrotzki, & Stacher, ). Individuals with BN report lower sensation intensities during increased stomach distention than controls (Zimmerli, Walsh, Guss, Devlin, & Kisseleff, ) but show elevated thermal (Yamamotova, Papezova, & Uher, ) and mechanical pain thresholds (de Zwaan et al, ).…”

The anticipation and perception of affective touch in women with and recovered from Anorexia Nervosa

“…Then, participants were asked to place their left arm palm facing down on a table, with the experimenter sitting in front of them. The experimenter marked two adjacent stroking areas, each measuring 9cm long x 4cm wide, with a washable marker on the hairy skin of their forearm as in previous studies (wrist crease to elbow; Crucianelli et al, 2013Crucianelli et al, , 2016Crucianelli et al, , 2018.…”