AUTHOR=Youn Jinyoung , Kim Mansu , Park Suyeon , Kim Ji Sun , Park Hyunjin , Cho Jin Whan 

TITLE=Pallidal Structural Changes Related to Levodopa-induced Dyskinesia in Parkinson's Disease

JOURNAL=Frontiers in Aging Neuroscience

VOLUME=Volume 14 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/aging-neuroscience/articles/10.3389/fnagi.2022.781883

DOI=10.3389/fnagi.2022.781883

ISSN=1663-4365

ABSTRACT=Background: Despite clinical impact of levodopa-induced dyskinesia (LID) in Parkinson’s disease (PD), the mechanism, especially role of basal ganglia (BG), is not fully elucidated yet. We investigated the BG structural changes related to LID in PD using a surface-based shape analysis technique.
Methods: We recruited PD patients who developed LID within 3 years (LID group, 28 patients) and who did not develop after 7 years (non-LID group, 35 patients) from levodopa treatment for the extreme case-control study. BG structure volumes were measured from volumetry analysis, and the surface-based morphometry feature (i.e., Jacobian) from the subcortical surface vertices. We compared the volume and Jacobian of meshes in the regions between the two groups. We also performed correlation analysis of between local atrophy and the severity of LID. Additionally, we evaluated structural connectivity profiles from globus pallidus interna and externa (GPi and GPe) to other brain structures based on the group comparison.
Results: The demographic and clinical data showed no significant difference except for disease duration, treatment duration, parkinsonism severity, and levodopa equivalent dose. The LID group had more local atrophies of vertices in the right GPi than the non-LID group, despite no difference in volumes. Further, the LID group demonstrated significantly reduced structural connectivity between left GPi and thalamus.
Conclusion: This is the first demonstration of distinct shape alterations of basal ganglia structures, especially GPi, related to LID in PD. Considering both direct and indirect BG pathways share the connection between GPi and thalamus, BG pathway plays crucial roles in development of LID.