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

Abstract

Disruptions in reward processing and anhedonia have long being considered as possible contributors to the aetiology and maintenance of Anorexia nervosa (AN). Recently, interoceptive deficits have also been observed in AN, including reduced tactile pleasure.However, the extent to which this tactile anhedonia is specifically liked to an impairment in a specialized, interoceptive C tactile system originating at the periphery, or a more top-down mechanism in the processing of pleasant tactile stimuli remains debated. Here, we investigated two related hypotheses. First, we examined whether the differences, between patients with AN and healthy controls in the perception of pleasantness of touch stimuli delivered in a CToptimal manner versus a CT non-optimal manner would also be observed in patients recovered from AN. This is important as tactile anhedonia in acute patients may be the secondary result of prolonged malnutrition, rather than a deficit that contributed to the development of the disorder. Second, we examined whether these three groups would also differ in their top-down, anticipatory beliefs about the perceived pleasantness of different materials touching the skin, and to what degree such top-down beliefs and related impairments in alexithymia and interoceptive sensibility would explain any differences in perceived tactile plesantness. To this end, we measured the anticipated pleasantness of various materials touching the skin and the perceived pleasantness of light, dynamic stroking touches applied to the forearm of 27 women with AN, 24 women who have recovered and 30 healthy controls using C Tactile (CT) afferents-optimal (slow) and non-optimal (fast) velocities. Our results showed that both clinical groups anticipated tactile experiences and rated delivered tactile stimuli as less pleasant than healthy controls, but the latter difference was not related to the CT optimality of the stimulation. Instead, differences in how CT optimal touch were perceived were predicted by differences in top-down beliefs, alexithymia and interoceptive sensibility. Thus, this study concludes that tactile anhedonia in AN is not the secondary result of malnutrition but persists as a trait even after otherwise successful recovery of AN and also it not linked to a bottom-up interoceptive deficit in the CT system, but rather to a learned, defective top-down anticipation of pleasant tactile experiences.

Does Nice or Nasty Matter? The Intensity of Touch Modulates the Rubber Hand Illusion

“…This is particularly evident in psychopathology, for example in the contexts of eating disorders (EDs; Teaford et al, 2021 ). Indeed, ED patients present with profound alterations in body perception that include deficits in interoception and multisensory integration as well as abnormalities in body representation ( Crucianelli et al, 2020 ; Sacchetti et al, 2021 ; Teaford et al, 2021 ). Interestingly, these alterations in body perception have been found to be coupled with higher-order psycho-social impairments and specifically with difficulties in understanding others’ behaviors and emotions ( Caglar-Nazali et al, 2014 ; Bora and Köse, 2016 ).…”

Topical heterogeneity in affective touch: Does it impact body image?

“…Further studies have recently shown that both acute and recovered AN (RAN) patients also display a reduced responsivity to the anticipation of CT-optimal touch, both in terms of neural response localized to the ventral mid-insula, and in terms of predicted pleasantness of touch [32,36]. Taken together, these findings suggest that in AN there is a dysregulation in the ability to correctly predict and interpret interoceptive stimuli, including CT-based pleasantness of touch.…”

“…CC-BY 4.0 International license perpetuity. It is made available under a preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in The copyright holder for this this version posted November 30, 2020. ; https://doi.org/10.1101/2020.11.30.403600 doi: bioRxiv preprint endures even after an otherwise successful recovery [31,32]. Anorexia Nervosa is a psychiatric condition characterised by profound disturbances in eating behaviours and body image [33], accompanied by impairments in social cognition and in the perception of interoceptive bodily sensations [34,35].…”

“…Anorexia Nervosa is a psychiatric condition characterised by profound disturbances in eating behaviours and body image [33], accompanied by impairments in social cognition and in the perception of interoceptive bodily sensations [34,35]. These impairments might also extend to the interoceptive modality of affective touch, indicating the presence of a bodily-encoded anhedonia in interpersonal interactions [32].…”

Out of touch: Touch deprivation and affective touch perception during the COVID-19 pandemic

“…In addition, several factors that might influence the perception of CT-optimal touch were taken into account, including the presence of mental disorders (Croy et al, 2016;Crucianelli, Cardi, Treasure, Jenkinson, & Fotopoulou, 2016;Crucianelli et al, 2020) , age (Sehlstedt et al, 2016), gender (Ilona Croy et al, 2014), and neurological and skin conditions (Liljencrantz & Olausson, 2014), Following Sailer and Ackerley (2019) "use it or lose it principle" we expected that an increase in touch deprivation would be related to a decrease in pleasantness ratings of CT-optimal touch videos.…”