Gait initiation deficits in Parkinson's disease with freezing of gait: A large-scale force platform study of anticipatory postural adjustments

Introduction

Freezing of gait (FoG) is a debilitating motor symptom in Parkinson's disease (PD), often occurring during step initiation due to impaired anticipatory postural adjustments (APAs). Previous studies show inconsistent findings regarding APA alterations in people with PD with FoG (PwPD + FoG) and without FoG (PwPD-FoG). This study aimed to investigate APA characteristics using a force platform to assess postural control deficits associated with FoG.

Methods

We analyzed baseline data from 130 PwPD (70 with FoG) and 41 healthy controls. A force platform during self-initiated stepping measured APA duration, amplitude, and step amplitude. All participants with PD were tested in the ON medication. One-way ANOVA and ANCOVA (controlling for UPDRS-III and medication) were conducted to compare groups.

Results

APA duration was significantly shorter in Healthy compared to PwPD + FoG and PwPD-FoG, with no difference between PD groups. Step amplitude was significantly lower in PwPD + FoG compared to Healthy and PwPD-FoG, but this difference was insignificant after covariate. APA mediolateral amplitude followed PD + FoG < PD-FoG < Healthy; ANCOVA confirmed lower values in PwPD + FoG compared to PwPD-FoG. APA anteroposterior amplitude was also reduced in PwPD + FoG relative to PwPD-FoG and Healthy, with ANCOVA confirming significantly lower values in PwPD + FoG versus PwPD-FoG. NFOG-Q scores were negatively correlated with mediolateral and anteroposterior APA amplitudes.

Conclusion

FoG in PD is associated with reduced APA amplitude (mediolateral and anteroposterior), suggesting postural control deficits persist despite dopaminergic medication. These findings highlight the importance of interventions targeting APA improvements to mitigate gait initiation failures in PwPD + FoG.