Relationship between anticipatory postural adjustments at step initiation and freezing severity in individuals with Parkinson's disease

Abstract

Introduction: Parkinson's disease is characterized by motor changes that include postural instability and is also associated with the phenomenon of gait freezing. Freezing of gait, or FOG, is related to their activity and participation, and is often assessed in the clinical setting using scales. However, the posturographic characteristics associated with the phenomenon of FOG in individuals with PD are unknown. Objective: The aim of the present study was to verify if there is a relationship between the anticipatory postural adjustments and the Freezing March Questionnaire (FOG-Q) in a sample of individuals with PD. Methods: In this cross-sectional
study, 16 individuals with PD were evaluated using clinical scales and posturography. The FOG-Q scale was used to assess the level of gait impairment in relation to initial freezing. A force platform was used to measure the center of pressure of the feet (COP) displacements and to evaluate the APA, divided into APA1 (initial step) and APA2 (single leg support). In the “on” phase of PD medication, participants were instructed to position themselves on the force platform and start the step after a verbal command.
Spearman correlation analysis (rho) was used to measure the association between FOG scores and COP duration, amplitude and velocity during the APA1 and APA2 phases of the beginning of the step, assuming a statistical threshold of 5%. Results: As a main result, we observed a moderate, negative association between APA1 amplitude and FOG scores (rho = -0.548, P = 0.028, rho confidence interval from -0.821 to -0.072). Conclusion: Therefore, the FOG clinical scale is related to the anticipatory postural adjustments corresponding to the first step at the beginning of gait.