Should disease duration be linked to freezing of gait in Parkinson's disease?


Freezing of gait (FOG) is one of the most debilitating symptoms of Parkinson's disease (PD). In order to allow time for intervention strategies to be introduced early on, it is important to be able to predict who may become 'freezers' after a PD diagnosis. It has been a long-standing clinical assumption that increased disease duration increases the likelihood of someone becoming a freezer, but FOG and disease duration were only secondary measures with no statistical correlations to uncover any true associations between these variables. The purpose of this study was to observe the role disease duration has in determining who becomes a freezer. To do this, demographic information for 160 participants was retrospectively collected and divided into freezers (n=20), non-freezers (n=114), and individuals that converted into freezers (n=26). Correlations and eta coefficients were computed for disease duration and FOG state. Only 14.29% of the variance of the FOG state could be accounted for by disease duration. Additionally, a weak association of 6.66% was found between the two variables. This shows that while there might be a slight association between FOG and disease duration, it is unlikely that a freezer simply evolves as a result of disease duration, as has been assumed by many clinicians and researchers. Future research should focus on identifying variables that can predict who will become a freezer in their lifetime. Results will be discussed in terms of variables that may prove worthy of investigation as potential biomarkers for freezing of gait. .