Substantia Nigra Hyperechogenicity in Parkinson's Disease and Related Disorders: A Follow-up Study

Abstract

Background: Previous studies have shown that the hyperechogenic area of the substantia nigra (SN) does not change over the disease course in patients with Parkinson's disease (PD). However, longitudinal changes in SN echogenicity in patients with atypical parkinsonian syndrome (APS) remain unclear. We evaluated the change in SN hyperechogenic area over time in patients with PD and those with APS, including multiple system atrophy (MSA) and progressive supranuclear palsy (PSP).

Methods: A total of 22 patients with parkinsonism (14 PD, aged 71.0 ± 8.3 years; 8 APS (6 PSP and 2 MSA), aged 69.9 ± 9.6 years) who underwent transcranial sonography twice (≥6 months apart) were included in this study. Patients with insufficient temporal bone windows were excluded.

Results: The mean interval between examinations was 24.7 ± 15.3 months. No differences were detected in the hyperechogenic SN area between the first and second examinations (all patients, 0.17 ± 0.09 cm² vs. 0.17 ± 0.08 cm², p = 0.67; PD, 0.20 ± 0.08 cm² vs. 0.20 ± 0.08 cm², p = 0.45; APS, 0.11 ± 0.06 cm² vs. 0.12 ± 0.06 cm², p = 0.37, respectively). In both groups, there were no correlations between the hyperechogenic SN area and disease duration or severity.

Conclusion: The hyperechogenic SN area did not change over the disease course in PD or APS patients.