孤独症谱系障碍患者的面部表情敏感性缺陷：任务性质的影响与干预启示

The deficit of emotional sensitivity to facial expression in Autism Spectrum Disorder:task-based analyses and insights into intervention

大量研究指出,孤独症谱系障碍(ASD)患者存在面部表情识别和理解的缺陷,这是患者社会功能受损的核心来源.对面孔表情具有情绪敏感性是理解与识别表情的先决条件,但ASD患者对面部表情的情绪敏感性迄今尚未得到系统分析.本文将ASD与面部表情知觉的相关研究按照实验任务类型进行了分类,发现该领域研究可划分为3种任务类型:外显表情观察任务、引导注视点观察任务和内隐表情观察任务.由此重点对比了ASD患者在3种任务类型下的行为,外周生理反应与脑激活模式.结果发现,ASD患者对面孔表情的情绪敏感性缺陷主要体现在外显表情观察与引导注视点观察任务中.相比上述两种要求被试有意注意面孔表情特征的任务,ASD患者在内隐表情观察任务中能对面部表情表现出与正常被试相似或更大的注意偏向及杏仁核激活.这提示ASD患者并非完全缺乏对面部表情的情绪敏感性;而很可能是在有意注意表情的条件下,该群体的面孔适应困难使之产生了对面孔情绪特征的回避,故无法有效激活以杏仁核为核心的情感神经环路.据此,本文提出了对ASD患者的表情敏感性缺陷的干预设想,即通过无意识地、内隐地训练ASD患者维持对面孔情绪特征的注意很可能会改善其表情敏感性和面孔适应能力,这种方式对于ASD的临床干预和社会能力的提高或将具有重要意义.

Numerous studies have indicated the common deficit of Autism Spectrum Disorder （ASD） in recognizing and understanding facial expressions, which is a major cause of the ASD＇s social dysfunction. Emotional sensitivity to facial expression is a prerequisite of understanding and recognizing facial expression. However, the emotion sensitivity to facial expressions in ASD has yet to be systematically analyzed to date. After systematic analysis of existing studies about ASD and the perception of facial expression, we found that the existing literature could be sorted into three task categories： explicit observation of facial emotion, fixation-oriented observation of facial emotion, or implicit observation of facial emotion. We then analyzed the peripheral physiological and neuroimaging data of ASD and facial emotion perception under those three conditions. We found that the lack of emotion sensitivity to facial expressions was mainly observed irt the explicit or fixation-oriented affect recognition tasks, either of which required intentional focus on key features of facial expression. By contrast, subjects with ASD exhibited similar or even larger amygdala activation compared to healthy subjects when implicitly processing emotional facial expressions. These results suggest that individuals with ASD are not lacking emotional sensitivity to facial expression in nature. Instead, the insufficient face adaptation and the face-specific hyperarousal that characterize ASD may lead the patients to avoid attention orienting to facial expression, which in turn leads to deficient activation in emotion-related neural circuits. Based on these evidences, we propose a new method of intervention for improving the facial emotion sensitivity in ASD patients. That is, training ASD patients to perceive emotional faces implicitly, without conscious awareness of facial emotion observation, is a potentially promising approach to improve autistic individuals＇ neural sensitivity and adaptation to facial expressions. This may be an important candidate method for the intervention of autistic symptoms and the enhancement of their social functions.