Objective: To investigate the relationship between executive function and frontoparietal network (FPN) functional connectivity in Parkinson’s disease patients with freezing of gait (PD-FOG).

Background: FPN disruption and executive dysfunction have been reported in PD-FOG. It has been suggested that executive dysfunction and FOG may share a common underlying pathophysiology. Alterations in FPN functional connectivity may play a role in this shared pathophysiology.

Methods: Preliminary analyses included 7 PD-FOG, 4 PD patients without FOG (PD-nFOG), and 8 healthy controls (HCs) from the Center for Neurodegeneration and Translational Neuroscience. Rey Auditory Verbal Learning Test (RAVLT), Trail Making Test (TMT), WAIS-IV Digit Span (DS), WAIS-IV Letter Number Sequencing (LNS), Animal Naming, D-KEFS Verbal Fluency, and D-KEFS Color-Word Interference tests were used to assess executive functioning. All PD-FOG and PD-nFOG performed the assessment in levodopa ON state. All subjects had resting state functional magnetic resonance imaging (fMRI) with a 3T scanner. Independent component analysis (ICA) was used to assess FPN functional connectivity. Correlational analyses between ICA measures and executive function scores were computed.

Results: Demographics and disease features were similar between groups [table 1]. PD-nFOG and HCs did not differ on any measures of executive function or FPN functional connectivity in the ON state [figure 1]. PD-FOG patients performed worse than controls in LNS, TMT Part A, D-KEFS Verbal Fluency, and D-KEFS Color Word Interference-color naming and inhibition [table 2]. Functional connectivity of the supramarginal gyrus (SMG) was the only difference between PD-FOG and HCs in the ON state [figure 1]. Within PD-FOG, FPN functional connectivity was positively correlated with D-KEFS Verbal Fluency- letter fluency and LNS scores; and negatively correlated with D-KEFS Color-Word Interference- inhibition.

Conclusions: PD-FOG have executive deficits, and decreased FPN functional connectivity is associated with working memory, processing speed, and inhibition deficits. Functional connectivity of the SMG was abnormal in PD-FOG compared to HC, and this region is activated for phonological processing during both language and verbal working memory tasks, which could explain our findings. A bigger sample recruited for this ongoing study will help reveal associations between executive dysfunction and functional connectivity alterations within PD-FOG more reliably.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/executive-function-and-frontoparietal-network-association-in-freezing-of-gait/