Affective touch in anorexia nervosa: Exploring the role of social anhedonia and lifespan experiences.

BACKGROUND: The pleasantness of a gentle and slow, namely affective, touch experienced in interpersonal interactions motivates social closeness. In anorexia nervosa (AN), independent evidence suggests lower pleasantness of affective touch, as well as social withdrawal. We aim to probe both the experience of affective touch and its possible association with social anhedonia and lifespan experiences of affective bodily contacts in AN. METHODS: The pleasantness of affective and non-affective touch was compared between fourteen women with AN and fourteen healthy women. Stimuli were traditionally delivered with a brush, with the experimenter's hand, as novelty, and with a stick, as control. The pleasantness of imagined and real touch was probed. Self-report questionnaires assessed social anhedonia and lifespan experiences of affective touch. RESULTS: A preserved pleasantness of affective touch emerged in AN in both the imagery and real task, despite higher social anhedonia and less lifespan experience of affective touch than healthy women. LIMITATIONS: Affective touch involves loved ones; thus, the experimenter's touch may not resemble real-life interactions. Future research may take advantage of imagery procedures to solve this issue. CONCLUSIONS: Body-oriented therapy for AN recognizes touch as a therapeutic tool: ascertaining how touch is experienced is crucial to maximize rehabilitative outcomes. Furthermore, clarifying the possible interplay between interpersonal difficulties in AN and affective touch is especially relevant considering the possible role of the attachment style, which is intensively debated in AN, on affective touch.

Reduced Temporal Sensitivity in Obesity: Evidence From a Simultaneity Judgement Task.

Preliminary evidence showed a reduced temporal sensitivity (i.e., larger temporal binding window) to audiovisual asynchrony in obesity. Our aim was to extend this investigation to visuotactile stimuli, comparing individuals of healthy weight and with obesity in a simultaneity judgment task. We verified that individuals with obesity had a larger temporal binding window than healthy-weight individuals, meaning that they tend to integrate visuotactile stimuli over an extended range of stimulus onset asynchronies. We point out that our finding gives evidence in support of a more pervasive impairment of the temporal discrimination of co-occurrent stimuli, which might affect multisensory integration in obesity. We discuss our results referring to the possible role of atypical oscillatory neural activity and structural anomalies in affecting the perception of simultaneity between multisensory stimuli in obesity. Finally, we highlight the urgency of a deeper understanding of multisensory integration in obesity at least for two reasons. First, multisensory bodily illusions might be used to manipulate body dissatisfaction in obesity. Second, multisensory integration anomalies in obesity might lead to a dissimilar perception of food, encouraging overeating behaviours.

Mental representation of the body in action in Parkinson's disease.

Mixed findings characterize studies in Parkinson's disease (PD): some studies indicate a relationship between physical impairments and the ability to mentally represent the body, while others suggest spared abilities for this cognitive function. To clarify the matter, in the present study we explored the mental representations of the body in action in the same PD patients, taking also into account lateralization of symptoms and visual imagery skills. 10 PD patients with left- (lPD), 10 with right (rPD) lateralized symptoms (lPD), and 20 matched healthy controls have been recruited for the study. All patients were screened for neuropsychological impairments. To explore a more implicit component we used the hand laterality task (HLT), while the mental motor chronometry (MMC) was used to explore a more explicit one. Two control tasks, with objects instead of body parts, were administered to control for visual imagery skills. In the HLT, we detected the effects of biomechanical constraints effects in both controls and PD patients. In the latter group, importantly, this was true independently from lateralization of symptoms. In the MMC, we found the expected positive correlation between executed and imagined movements for both hands in controls only, while all PD patients, again independently form lateralization, only showed this effect for the left hand. In terms of visual imagery, only rPD patients differed from controls when asked to implicitly rotate letters, and in terms of accuracy only. However, this difference is explained by executive functions measured through the neuropsychological assessment rather than by a "pure" visual imagery impairment. In summary, our findings suggest that two different aspects of the mental representations of the body in action, one more implicit and the other more explicit, can be differently affected by PD. These impairments are unlikely explained by a basic visual imagery deficit. When present, impairments concern a higher dimension, related to motor functions and awareness, and not driven by sensory impairments, as shown by the independence of effects from physical laterality of symptoms.