Department of Clinical, Educational and Health Psychology, University College London, London, UK.
Department of Neuroimaging Science, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.
BMJ Open. 2019 Mar 15;9(3):e024913. doi: 10.1136/bmjopen-2018-024913.
Anorexia nervosa (AN) is an eating disorder characterised by restriction of energy intake, fears of gaining weight and related body image disturbances. The oxytocinergic system has been proposed as a pathophysiological candidate for AN. Oxytocin is a neuropeptide involved in bodily processes (eg, breast feeding) and in the onset of social behaviours (eg, bonding). Studies investigating the effect of intranasal oxytocin (IN-OT) in AN showed that it can improve attentional bias for high-calorie food and fat bodies stimuli, and related stress. However, less is known about the effect of IN-OT on bodily awareness and body image distortions, key features of the disorder linked to its development, prognosis and maintenance. Here, we aim to investigate the effect of IN-OT on the perception of affective, C-tactile-optimal touch, known to be impaired in AN and on multisensory integration processes underlying a body ownership illusion (ie, rubber hand illusion). For exploratory purposes, we will also investigate the effect of IN-OT on another interoceptive modality, namely cardiac awareness and its relationship with affective touch.
DESIGN, METHODS AND ANALYSIS: Forty women with AN and forty matched healthy controls will be recruited and tested in two separate sessions; self-administering IN-OT (40 IU) or placebo, intranasally, in a pseudo-randomised manner. The data from this double-blind, placebo-controlled, cross-over study will be analysed using linear mixed models that allow the use of both fixed (treatment levels) and random (subjects) effects in the same analysis. To address our main hypotheses, separate analyses will be run for the affective touch task, where the primary outcome dependent variable will be the pleasantness of the touch, and for the rubber hand illusion, where we will investigate multisensory integration quantified as subjective embodiment towards the rubber hand. In the latter, we will manipulate the synchronicity of touch and the size of the hand.
Ethics approval has been obtained by National Research Ethics Service NRES Committee London (Queen's Square Committee, ref number 14/LO/1593). The results will be disseminated through conference presentations and publication in peer-reviewed journals.
神经性厌食症（AN）是一种以能量摄入受限、对体重增加的恐惧以及相关的身体形象障碍为特征的进食障碍。神经肽催产素系统被认为是 AN 的一种病理生理学候选物。催产素是一种参与身体过程（例如哺乳）和社交行为（例如联系）的神经肽。研究表明，鼻内给予催产素（IN-OT）可以改善对高热量食物和脂肪身体刺激的注意力偏向，以及相关的压力。然而，对于 IN-OT 对身体意识和身体形象扭曲的影响知之甚少，这些特征与疾病的发展、预后和维持有关。在这里，我们旨在研究 IN-OT 对情感感知的影响，以及对 C-触敏最佳触觉的影响，已知 AN 中存在这种触觉受损，以及对身体所有权错觉（即橡胶手错觉）的多感觉整合过程的影响。出于探索目的，我们还将研究 IN-OT 对另一种内脏感觉模式的影响，即心脏意识及其与情感触觉的关系。
设计、方法和分析：将招募 40 名 AN 女性患者和 40 名匹配的健康对照组，并在两个单独的测试中进行测试；以伪随机方式分别自我施用 IN-OT（40IU）或安慰剂，经鼻内给药。这项双盲、安慰剂对照、交叉研究的数据将使用线性混合模型进行分析，该模型允许在同一分析中同时使用固定（治疗水平）和随机（受试者）效应。为了验证我们的主要假设，我们将分别对情感触觉任务进行分析，其中主要的因变量是触觉的愉悦程度，以及对橡胶手错觉进行分析，在后者中，我们将研究多感觉整合，表现为对橡胶手的主观体验。在后者中，我们将操纵触觉的同步性和手的大小。
国家伦理服务局 NRES 委员会伦敦（皇后广场委员会，编号 14/LO/1593）已批准该伦理。研究结果将通过会议演讲和在同行评议期刊上发表来传播。
