Olfactory dysfunction (OD) is a highly frequent early non-motor symptom of Parkinson’s disease (PD). An important step to potentially use OD for the development of early diagnostic tools of PD is to differentiate PD-related OD from other forms of non-parkinsonian OD (NPOD: postviral, sinunasal, post-traumatic, and idiopathic OD). Measuring non-olfactory chemosensory modalities, especially the trigeminal system, may allow to characterize a PD-specific olfactory profile. We here review the literature on PD-specific chemosensory alteration patterns compared with NPOD. Specifically, we focused on the impact of PD on the trigeminal system and particularly on the interaction between olfactory and trigeminal systems. As this interaction is seemingly affected in a disease-specific manner, we propose a model of interaction between both chemosensory systems that is distinct for PD-related OD and NPOD. These patterns of chemosensory impairment still need to be confirmed in prodromal PD; nevertheless, appropriate chemosensory tests may eventually help to develop diagnostic tools to identify individuals at risks for PD.

中文翻译：

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帕金森病患者的嗅觉-三叉神经相互作用

嗅觉功能障碍 (OD) 是帕金森病 (PD) 的一种非常常见的早期非运动症状。潜在地使用 OD 开发 PD 早期诊断工具的一个重要步骤是将 PD 相关 OD 与其他形式的非帕金森 OD（NPOD：病毒后、鼻窦、创伤后和特发性 OD）区分开来。测量非嗅觉化学感应方式，尤其是三叉神经系统，可以表征 PD 特异性嗅觉特征。我们在此回顾与 NPOD 相比有关 PD 特异性化学感觉改变模式的文献。具体来说，我们关注 PD 对三叉神经系统的影响，特别是嗅觉和三叉神经系统之间的相互作用。由于这种相互作用似乎以特定疾病的方式受到影响，我们提出了两种化学感应系统之间相互作用的模型，该模型对于 PD 相关的 OD 和 NPOD 是不同的。这些化学感觉障碍的模式仍然需要在前驱 PD 中得到证实；然而，适当的化学感应测试最终可能有助于开发诊断工具，以识别有 PD 风险的个体。