Decreased interhemispheric homotopic connectivity in Parkinson's disease patients with freezing of gait: A resting state fMRI study

Abstract

Introduction: Freezing of gait is a common complaint in patients with Parkinson's disease (PD). However, the neural bases of freezing of gait in PD remain uncertain. Existing studies on PD patients with freezing of gait (PD-FOG+) have reported damage of the corpus callosum, the largest commissural bundle of the brain. Thus, in this study we explored homotopic connectivity to investigate FOG-related interehemispheric alterations METHODS: A total of 21 PD-FOG + patients, 33 PD patients without freezing of gait (PD-FOG-), and 24 matched healthy controls were recruited. All PD patients were evaluated via the FOG questionnaire (FOGQ) and all subjects had a resting state functional magnetic resonance imaging (rs-fMRI) scan. The pattern of the homotopic connectivity was measured with the voxel-mirrored homotopic connectivity (VMHC) approach.

Result: The PD-FOG + patients showed decreased VMHC values in the inferior parietal lobe (IPL) compared to both PD-FOG-patients and healthy controls. In PD-FOG + patients, the mean VMHC values in the IPL were negatively correlated with the FOGQ scores. Receiver operating characteristic curves analyses revealed that the VMHC in the IPL had discriminatory function distinguishing PD-FOG + patients from PD-FOG-patients or healthy controls.

Conclusion: Decreased VMHC values of PD-FOG + patients relative to PD-FOG- and healthy controls in IPL maybe a unique feature for PD-FOG+ and it may have the ability to separate PD-FOG + patients from PD-FOG- and healthy controls.

Keywords: Freezing of gait; Parkinson's disease; Resting-state fMRI; Voxel-mirrored homotopic connectivity.