Abstract

Levodopa-induced dyskinesias are common motor complication of Parkinson’s disease after 4–6 years of treatment. The hallmarks of dyskinesias include unilateral onset and the tendency to appear on the more affected body sides. There is a growing literature documenting the lateralization abnormalities are associated with the emergence of dyskinesias. Our investigation aimed to explore interhemispheric functional and its corresponding morphological asymmetry. A total of 22 dyskinetic patients, 23 nondyskinetic patients, and 26 controls were enrolled. Resting-state functional magnetic resonance imaging scans were performed twice before and after dopaminergic medication. Voxel-mirrored Homotopic Connectivity (VMHC) and Freesurfer were employed to assess the synchronicity of functional connectivity and structural alternations between hemispheres. During OFF state, dyskinetic patients showed desynchronization of inferior frontal cortex (IFC) when compared to nondyskinetic patients. And during ON state, dyskinetic patients showed desynchronization of IFC and pre-supplementary motor area (pre-SMA) when compared to nondyskinetic patients. However, there was no corresponding significant asymmetries in cortical thickness. Moreover, the degree of desynchronization of IFC and pre-SMA in dyskinetic pateients during ON state were negatively correlated with the Abnormal Involuntary Movement Scale (AIMS) scores. Notably, among patients who showed asymmetrical dyskinesias, there was a significant negative correlation between VMHC values of IFC and dyskinesias symptom asymmetry. Our findings suggested that uncoordinated inhibitory control over motor circuits may underlie the neural mechanisms of dyskinesias in Parkinson’s disease and be related to its severity and lateralization.

Highlights

  • Levodopa-induced dyskinesias (LIDs), which are recognized as involuntary, principally chorea movements[1], occur in 40% of patients with Parkinson’s disease (PD) after 4–6 years of levodopa treatment[2]

  • We investigated the interhemispheric functional and structural coordination among dyskinetic, nondyskinetic PD patients and healthy controls by combining Voxel-mirrored Homotopic Connectivity (VMHC) and Freesurfer approaches

  • Our primary finding was that dyskinetic patients showed significantly reduced VMHC values in inferior frontal cortex (IFC) and pre-supplementary motor area (pre-supplementary motor area (SMA)) during ON phase and exhibited lower VMHC values in IFC during OFF phase, when compared to nondyskinetic patients

Read more

Summary

Introduction

Levodopa-induced dyskinesias (LIDs), which are recognized as involuntary, principally chorea movements[1], occur in 40% of patients with Parkinson’s disease (PD) after 4–6 years of levodopa treatment[2]. Some researchers noticed that there was pronounced increased cortical thickness and underactivity of the right side of inferior frontal cortex (IFC), while some literature showed bilateral functional or structural changes, with respect to patients without LIDs5–7. Another cohort manifested that higher striatal asymmetric index was more susceptive to develop dyskinesia[8]. These previous findings have preliminary results, the role of the interhemispheric functional asynchronization and its corresponding morphological asymmetry in the pathophysiology of LIDs still remains unclear

Methods
Results
Conclusion
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call