Objective: The purpose of this study is to assess how brain connectivity is altered in Parkinson’s disease (PD) patients with freezing of gait (FOG), and how PD dopaminergic medication influence these changes.

Background: FOG is a common motor symptom in PD that may have debilitating consequences for patients such as falls, and this, even if PD dopaminergic medication is taken. Thus, it is paramount to understand how the presence of FOG alters neural control of locomotion, and how altered connectivity between brain areas contribute to FOG.

Method: 30 adults with Parkinson’s disease, 15 with FOG and 15 without FOG, have been recruited. All participants performed two resting-state functional magnetic resonance imaging scans, one ON- and one OFF-medication (i.e. L-DOPA). A seed-based analysis has been used to identify regions across the entire brain whose activation is correlated with activation of the seeds (bilateral basal ganglia nuclei, the thalamus and the mesencephalic locomotor nuclei). A significant correlation between a seed region and a cluster of voxels indicates that those areas are functionally connected. Group differences have been determined using a mixed effect model, with the Gaussian random field theory to correction for multiple comparisons, and a cluster threshold and significance of, respectively, Z>2.3 and p<0.05. Medication state differences in functional connectivity will be determined using the same approach than for group differences.

Results: Preliminary results show that, during ON-medication state, FOG is associated with increased connectivity between several subcortical regions (i.e. bilateral thalamus, bilateral globus pallidus external and left putamen) and visual areas. Specifically, in patients without FOG, these subcortical regions are anti-coupled with visual areas, whereas in patients with FOG, they are positively coupled. Results from the medication state differences analysis will be presented at the meeting.

Conclusion: Our preliminary results highlight the possible involvement of altered visuospatial processing in the occurrence of FOG in the ON-medication state. Results of this study, which will be available for the congress, will improve our understanding of the relationship between FOG and dopaminergic medication by determining how brain connectivity changes related to FOG are modulated by L-DOPA.

« Back to 2019 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/are-there-associations-between-altered-brain-connectivity-and-dopaminergic-medication-in-parkinsons-disease-patients-with-freezing-of-gait/