Objective: to investigate the clinical and oculomotor associations with freezing of gait (FOG) in Chinese Parkinson’s disease (PD).

Background: FOG in PD has been reported to be associated with several clinical features such as more severe motor symptom, lower limb onset, cognitive impairment and higher daily dose of levodopa. However, the detailed clinical correlates are rare investigated in China, and the potential pathophysiology is not fully understood yet. Currently, there is a lack of biomarker for this subtype.

Method: From Jan 2017 to Dec 2019, a total of 210 PD patients were consecutively registered for FOG evaluation based on item-3 of the Freezing of Gait Questionnaire. We explored the demographic, motor and non-motor symptom differences in FOG positive (PD+FOG) versus negative (PD-FOG) group. 129 PD patients and 37 healthy controls (HC) also underwent oculomotor test via videonystagmography (VNG). Visually guided saccade latency, saccade accuracy and gain in smooth pursuit eye movement (SPEM) of horizontal axis were compared among PD+FOG, PD-FOG and HC group.

Results: Compared with PD-FOG (n=165), PD+FOG(n=45) had longer disease duration, more severe motor, cognitive, depressive and autonomic impairments, as well as higher daily levodopa equivalent dosage. FOG occurred more frequently in patients with wearing-off. Binary logistic regression showed that Unified PD Rating scale part III, Non-motor Symptom Questionnaire score and wearing-off were independent associated factors with FOG. VNG subgroup analysis demonstrated that PD had prolonged saccade latency and decreased SPEM gain relative to HC. In addition, PD+FOG(n=20) had increased saccade latency, in comparison with PD-FOG (n=109) or HC.

Conclusion: Our results validate that PD+FOG patients suffer from more severe motor and non-motor symptoms, indicating more extensive neurodegeneration in this subtype. Prolonged saccade latency could be a novel oculomotor biomarker for FOG in PD.

References: [1]Nemanich ST, Earhart GM. Freezing of gait is associated with increased saccade latency and variability in Parkinson’s disease. Clin Neurophysiol. 2016;127:2394–401. [2]Perneczky R, Ghosh BCP, Hughes L, Carpenter RHS, Barker RA, Rowe JB. Saccadic latency in Parkinson’s disease correlates with executive function and brain atrophy, but not motor severity. Neurobiol Dis. 2011;43:79–85. [3]Visser F, Bour LJ, Lee YX, Ten Brinke TR, van Rootselaar AF. Eye movement abnormalities in essential tremor versus tremor dominant Parkinson’s disease. Clin Neurophysiol. 2019;130:683–91.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/clinical-and-oculomotor-correlates-with-freezing-of-gait-in-chinese-parkinsons-disease/