LaChapelle D L, Hadjistavropoulos T, Craig K D
Department of Psychology, University of Regina, Saskatchewan, Canada.
Clin J Pain. 1999 Mar;15(1):13-23. doi: 10.1097/00002508-199903000-00004.
The goal was to study the utility of nonverbal facial expressions as a research tool for assessing pain in persons with intellectual disabilities. Biases and stereotypes related to age, gender, physical attractiveness, and intellectual disability that may influence the ability of observers to evaluate pain reactions were also examined.
Facial reactions to an intramuscular injection of 40 adults (mean age = 49.6 years) with an intellectual disability were videotaped and objectively examined using the Facial Action Coding System. Self-reported pain ratings were obtained using a Colored Visual Analogue Scale for pain. Pain reactions were also rated by untrained observers.
A significant proportion of participants (35%) was unable to provide valid self-report. The intensity of objectively coded facial activity as well as observer-rated pain intensity showed significant increases from baseline to injection segments. Observers' pain ratings were primarily determined by the intensity of facial activity and were not significantly affected by stereotypes based on perceived level of intellectual disability, gender, age, or physical attractiveness.
The findings support the validity of both objectively coded and observer-rated facial expressions of pain as research tools in treatment outcome studies involving persons with intellectual disabilities. Self-report has substantial limitations for the assessment of pain in this population.
本研究旨在探讨非言语面部表情作为评估智障人士疼痛的研究工具的效用。同时，还研究了年龄、性别、外貌吸引力和智力残疾等因素可能对观察者评估疼痛反应能力产生的偏见和刻板印象。
对40名成年智障人士（平均年龄 = 49.6岁）进行肌肉注射，并使用面部动作编码系统对面部反应进行录像和客观分析。使用彩色视觉模拟疼痛量表获取自我报告的疼痛评分。未受过训练的观察者也对疼痛反应进行评分。
相当一部分参与者（35%）无法提供有效的自我报告。从基线到注射阶段，客观编码的面部活动强度以及观察者评定的疼痛强度均显著增加。观察者的疼痛评分主要由面部活动强度决定，而不受基于感知的智力残疾水平、性别、年龄或外貌吸引力的刻板印象的显著影响。
研究结果支持在涉及智障人士的治疗结果研究中，客观编码和观察者评定的疼痛面部表情作为研究工具的有效性。自我报告在评估该人群的疼痛方面存在很大局限性。
