Otorhinolaryngology Research Center, Tehran University of Medical Sciences, Tehran, Iran.
Department of Biomedical Engineering (Center of Excellence), Amirkabir University of Technology, Tehran, Iran.
Iran J Med Sci. 2022 May;47(3):248-255. doi: 10.30476/IJMS.2021.89049.1977.
A major problem with the University of Pennsylvania Smell Identification Test (UPSIT) is its poor sensitivity for malingering detection in a group of people familiar with the test mechanism. This study aimed to evaluate the modification of UPSIT to detect anosmia malingering.
This was a pilot experimental study conducted in 2019 in Tehran. The participants were 60 healthy subjects classified into two groups of 30 people. The first group was requested to deliberately feign a negative result on the Iranian version of UPSIT, Iran Smell Identification Test (ISIT) (malingering group). The second group consisted of participants, who did not scratch the odorant part of ISIT during the tests (anosmia group). ISIT was modified in two steps. At each step, one incorrect option was deleted from the available choices. The number of each group's answers, altered away from the correct choice, was then calculated and compared.
The coached malingering group participants were able to feign anosmia in the original ISIT exam. In the modified ISIT, the number of answers changed from correct to wrong during the second stage (from three available choices to two choices) was significantly higher in the anosmia group (P<0.001). In the ROC analysis, the area under the curve was 0.92 (P<0.001). The cut-off of 4.5 for this test showed 93% sensitivity, 82% specificity, and 90% PPV and NPV.
The ISIT is not capable of detecting malingering in the coached participants, yet by deleting the choices step-by-step, the sensitivity and specificity of the test increased.
宾夕法尼亚大学嗅觉识别测试（UPSIT）的一个主要问题是，在熟悉测试机制的人群中，其对伪装性嗅觉缺失的检测灵敏度较差。本研究旨在评估 UPSIT 的修改版本以检测嗅觉缺失的伪装。
这是 2019 年在德黑兰进行的一项试点实验研究。参与者为 60 名健康受试者，分为两组，每组 30 人。第一组被要求故意在伊朗版 UPSIT（伊朗嗅觉识别测试，ISIT）上表现出阴性结果（伪装组）。第二组由未在测试过程中刮擦 ISIT 气味部分的参与者组成（嗅觉缺失组）。ISIT 在两个步骤中进行了修改。在每个步骤中，从可用选项中删除一个错误选项。然后计算并比较每个组偏离正确答案的答案数量。
受过训练的伪装组参与者能够在原始 ISIT 考试中表现出嗅觉缺失。在修改后的 ISIT 中，在第二阶段（从三个可用选项变为两个选项）中，嗅觉缺失组从正确答案变为错误答案的答案数量明显更高（P<0.001）。在 ROC 分析中，曲线下面积为 0.92（P<0.001）。该测试的 4.5 分截断值显示出 93%的灵敏度、82%的特异性、90%的阳性预测值和 90%的阴性预测值。
ISIT 无法检测到经过训练的参与者的伪装，但通过逐步删除选项，测试的灵敏度和特异性有所提高。
