Objective: To compare the frequency of Substantia Nigra hyperechogenicity (SN+) in patients with essential tremor (ET) and Parkinson’s disease (PD), to determine the frequency of premotor symptoms commonly described in PD (PD-PMS) in both groups and their association with SN+.

Background: Several studies have shown that certain patients with ET have an increased risk of developing PD. SN+ is found in 13-33% of patients with ET and can be considered a biomarker for PD risk in patients with ET. In addition, PD-PMS might contribute to identify this ET vulnerable group. There is scarce information regarding PD-PMS and their possible association with SN+ in patients with ET.

Method: We retrospectively reviewed medical records of 87 patients with PD and 63 with ET studied by transcranial ultrasound in our Hospital between April 2016 and July 2017. We excluded 26 PD and 10 ET patients due to transcranial insufficient insonability and incomplete data. Finally, 61 PD and 53 ET patients were included and compared. SN+ was defined as hyperechogenic area >0.20cm2. Analyzed variables: age, gender, frequency of SN+, maximum SN hyperechogenic area (MaxSN+), frequency of PD-PMS (RBD, hyposmia, constipation, depression) and their association with SN+. Statistical analysis: T-test, Chi-squared test and Spearman´s rank correlation coefficient. Statistical significance level: p <0.05.

Results: Significant differences between groups: frequency of SN+ (PD:52(85%); ET:20(37%), p<0.0001), MaxSN+ (PD:0.30±0.10cm2; ET:0.15±0.12cm2, p< 0.0001) and positive PD-PMS (PD:53(87%); ET:25(47%), p<0.0001). PD group: no association was found between PD-PMS and SN+. ET group: neither association nor correlation was found between PD-PMS and SN+.

Conclusion: Clinical and sonographic findings in PD patients were similar to those previously described. The frequency of SN+ and PD-PMS in patients with ET were significantly lower than in the PD group. The SN echogenicity was normal in the majority of ET patients with PD-PMS.

« Back to 2019 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/substantia-nigra-hyperechogenicity-in-parkinsons-disease-and-essential-tremor-and-its-association-with-premotor-symptoms-of-parkinsons-disease/