Interhemispheric synchrony differences between multiple system atrophy (Parkinsonian type) and Parkinson′s disease

Abstract

Objective To investigate the resting-state functional connectivity of the two hemispheres between multiple system atrophy (Parkinsonian type, MSA-P) and Parkinson′s disease (PD). Methods A total of 25 MSA-P, 29 PD patients and 29 well-matched healthy controls recruited in the Nanjing Brain Hospital Affiliated to Nanjing Medical University from June 2013 to December 2015 were scanned with resting-state functional magnetic resonance imaging for voxel mirrored homotopic correlation (VMHC) analysis. The Mini Mental State Examination, Montreal Cognitive Assessment, Frontal Assessment Battery and Unified Parkinson′s Disease Rating Scale-Ⅲ (UPDRS-Ⅲ) were used to assess the clinical symptom. Then the relationship between the change of VMHC values and severity of clinical symptoms was investigated. Results Compared with healthy controls, MSA-P and PD patients both showed decreased VMHC in bilateral cerebellum posterior lobe, precuneus gyrus, middle temporal gyrus, and postcentral gyrus. Compared with PD or healthy controls, MSA-P patients exhibited lower VMHC in bilateral putamen. Significant negative correlation between VMHC values of putamen and UPDRS-Ⅲ scores was found in MSA-P patients (r=-0.607, P=0.001). Conclusion These functional changes suggest that the abnormal interhemispheric synchrony probably plays an important role in pathophysiology of both MSA-P and PD, and abnormal VMHC values in putamen of MSA-P may be helpful in differentiating MSA-P from PD. Key words: Multiple system atrophy; Parkinson disease; Magnetic resonance imaging; Voxel mirrored homotopic correlation