Neuroscience Research Group (NRG), Universal Scientific Education and Research Network (USERN), Tehran, Iran.
School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
Neurol Sci. 2022 Aug;43(8):4745-4752. doi: 10.1007/s10072-022-06110-y. Epub 2022 May 4.
Olfactory dysfunction is one of the earliest non-motor symptoms (NMS) in Parkinson's disease (PD). There are contradictory results regarding the association of olfactory dysfunction and dopamine uptake in striatal nuclei among PD patients. It has been suggested that different motor subtypes of PD vary in the disease pathophysiology and progression. Thus, we hypothesized that there might be different associations between olfactory dysfunction and striatal dopaminergic neuronal loss among three motor subtypes of PD, namely, indeterminate, postural instability and gait difficulty (PIGD), and tremor-dominant (TD).
We recruited 162 healthy controls (HCs) and 464 drug-naïve PD patients from PPMI who underwent common PD scaling tests. Striatal binding ratios (SBRs) of DaTSCAN images in caudate and putamen nuclei were calculated. To assess the olfactory function, the University of Pennsylvania Smell Identification Test (UPSIT) was carried out.
The UPSIT score was significantly correlated with MDS-UPDRS part I (p value: 0.002, correlation coefficient: - 0.160), MDS-UPDRS part III (p value: 0.000, correlation coefficient: - 0.248), and SBR score in right (p value: 0.000, correlation coefficient: 0.240) and left caudate (p value: 0.000, correlation coefficient: 0.221) and right (p value: 0.000, correlation coefficient: 0.323) and left putamen (p value: 0.000, correlation coefficient: 0.335) nucleus in TD subtype. There were no significant correlations in HC, PIGD, and indeterminate subjects.
The olfactory dysfunction was correlated with dopamine transporter activity in striatal nuclei only in the TD subtype. Therefore, the olfactory dysfunction in PIGD and indeterminate subtype may not be a predictive factor for the future decrease in dopamine uptake.
嗅觉功能障碍是帕金森病（PD）最早出现的非运动症状（NMS）之一。在 PD 患者中，嗅觉功能障碍与纹状体核多巴胺摄取之间的相关性存在矛盾的结果。有人提出，不同的 PD 运动亚型在疾病的病理生理学和进展方面存在差异。因此，我们假设在 PD 的三种运动亚型（即运动不能确定型、姿势不稳和步态困难型（PIGD）和震颤主导型（TD））中，嗅觉功能障碍与纹状体多巴胺能神经元丢失之间可能存在不同的关联。
我们从 PPMI 招募了 162 名健康对照（HC）和 464 名未经药物治疗的 PD 患者，他们接受了常见的 PD 评分测试。计算了纹状体核 DaTSCAN 图像的结合比（SBR）。为了评估嗅觉功能，进行了宾夕法尼亚大学嗅觉识别测试（UPSIT）。
UPSIT 评分与 MDS-UPDRS 第一部分（p 值：0.002，相关系数：-0.160）、MDS-UPDRS 第三部分（p 值：0.000，相关系数：-0.248）以及右侧（p 值：0.000，相关系数：0.240）和左侧尾状核（p 值：0.000，相关系数：0.221）和右侧（p 值：0.000，相关系数：0.323）和左侧壳核（p 值：0.000，相关系数：0.335）的 SBR 评分显著相关。在 HC、PIGD 和不确定型患者中没有显著相关性。
嗅觉功能障碍仅与 TD 亚型的纹状体核多巴胺转运体活性相关。因此，PIGD 和不确定型亚型的嗅觉功能障碍可能不是未来多巴胺摄取减少的预测因素。
