Olfactory dysfunction (OD) is a prominent nonmotor symptom in Parkinson’s disease (PD), and OD is a supportive diagnostic criterion for PD. Physicians often ask their patients if they have noticed a smell disorder. This study evaluates the diagnostic validity of OD self-assessment in PD. To this end, 64 PD patients and 33 age-matched healthy controls were enrolled in a study assessing subjective and objective olfactory functioning. To examine subjective olfactory abilities, first, patients and controls had to classify their olfactory sense as “impaired” or “unimpaired,” comparable to a realistic situation in an outpatient setting. Second, to evaluate subjective olfactory acuity, a visual analogue scale (VAS) was used. Third, the Sniffin’ Sticks test battery was used as an objective instrument to diagnose OD. Categorical olfactory self-assessment predicts the classification normosmic versus hyposmic based on the global Sniffin’ Sticks score (TDI) with a sensitivity of 0.79 and a specificity of 0.45. TDI correlated significantly with the VAS (r = 0.297, ). The ROC curve analysis, using the VAS rating as a predictor for objective olfaction, revealed 42 as the best possible cutoff score with an area under the curve of 0.63. These results demonstrate that olfactory self-assessments show a low accuracy and are not suitable for the diagnosis of a smell disorder in PD. Objective measures are necessary to evaluate olfactory sense in clinical and research settings.

中文翻译：

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帕金森氏病患者嗅觉功能的无效自我评估可能会误导神经学家

嗅觉功能障碍（OD）是帕金森氏病（PD）的主要非运动症状，OD是PD的支持性诊断标准。内科医生经常问他们的病人是否注意到了嗅觉障碍。这项研究评估了OD自我评估在PD中的诊断有效性。为此，共有64位PD患者和33位年龄相匹配的健康对照组参加了一项评估主观和客观嗅觉功能的研究。为了检查主观嗅觉能力，首先，患者和对照者必须将其嗅觉分类为“受损”或“未受损”，这与门诊环境中的实际情况相当。其次，为了评估主观嗅觉敏锐度，使用了视觉模拟量表（VAS）。第三，Sniffin's Sticks测试电池被用作诊断OD的客观仪器。分类嗅觉自我评估可基于全球嗅探棒得分（TDI）预测分类正常与次要分类，敏感性为0.79，特异性为0.45。TDI与VAS显着相关（r  = 0.297，）。使用VAS等级作为客观嗅觉的预测指标的ROC曲线分析显示，42为最佳可能的截止得分，曲线下面积为0.63。这些结果表明，嗅觉自我评估的准确性较低，不适合诊断PD的嗅觉障碍。在临床和研究环境中，必须采取客观措施来评估嗅觉。