Corneal confocal microscopy may help to distinguish Multiple System Atrophy from Parkinson's disease

Xuebin Niu; Peixiao Yin; Chenyang Guan; Qiuyue Shao; Guiyun Cui; Kun Zan; Chuanying Xu

doi:10.1038/s41531-024-00680-8

Corneal confocal microscopy may help to distinguish Multiple System Atrophy from Parkinson's disease

NPJ Parkinsons Dis. 2024 Mar 16;10(1):63. doi: 10.1038/s41531-024-00680-8.

Authors

Xuebin Niu^{1

2}, Peixiao Yin^{1

2}, Chenyang Guan^{1

2}, Qiuyue Shao^{1

2}, Guiyun Cui^{1

2}, Kun Zan^{3

4}, Chuanying Xu^{5

6}

Affiliations

¹ Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu, China.
² Department of Neurology, The First Clinical College, Xuzhou Medical University, Xuzhou, Jiangsu, China.
³ Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu, China. zankun0608@163.com.
⁴ Department of Neurology, The First Clinical College, Xuzhou Medical University, Xuzhou, Jiangsu, China. zankun0608@163.com.
⁵ Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu, China. xucy2022@yeah.net.
⁶ Department of Neurology, The First Clinical College, Xuzhou Medical University, Xuzhou, Jiangsu, China. xucy2022@yeah.net.

Abstract

Multiple system atrophy (MSA) and Parkinson's disease (PD) have clinical overlapping symptoms, which makes differential diagnosis difficult. Our research aimed to distinguish MSA from PD using corneal confocal microscopy (CCM), a noninvasive and objective test. The study included 63 PD patients, 30 MSA patients, and 31 healthy controls (HC). When recruiting PD and MSA, questionnaires were conducted on motor and non-motor functions, such as autonomic and cognitive functions. Participants underwent CCM to quantify the corneal nerve fibers. Corneal nerve fiber density (CNFD) and corneal nerve fiber length (CNFL) values in MSA are lower than PD (MSA vs. PD: CNFD, 20.68 ± 6.70 vs. 24.64 ± 6.43 no./mm², p < 0.05; CNFL, 12.01 ± 3.25 vs. 14.17 ± 3.52 no./mm², p < 0.05). In MSA + PD (combined), there is a negative correlation between CNFD and the Orthostatic Grading Scale (OGS) (r = -0.284, p = 0.007). Similarly, CNFD in the only MSA group was negatively correlated with the Unified Multiple System Atrophy Rating Scale I and II (r = -0.391, p = 0.044; r = -0.382, p = 0.049). CNFD and CNFL were inversely associated with MSA (CNFD: β = -0.071; OR, 0.932; 95% CI, 0.872 ~ 0.996; p = 0.038; CNFL: β = -0.135; OR, 0.874; 95% CI, 0.768-0.994; p = 0.040). Furthermore, we found the area under the receiver operating characteristic curve (ROC) of CNFL was the largest, 72.01%. The CCM could be an objective and sensitive biomarker to distinguish MSA from PD. It visually reflects a more severe degeneration in MSA compared to PD.