Side of symptom onset not affects freezing of gait in Parkinson's disease

Abstract

Background: At disease onset, patients with Parkinson’s disease (PD) typically report one side of the body to be more affected than the other. Previous studies have reported that this motor symptom asymmetry is associated with asymmetric dopaminergic degeneration in the brain. Recent study suggested Freezing of Gait (FoG) exhibit dysfunction in a number of cortical and subcortical regions, possibly with asymmetric dysfunction towards the right hemisphere. Here, we test the hypothesis that FoG tend to appear more frequently on left side onset PD (L-PD) compare to right side onset PD (R-PD). Purpose:This study aimed at investigating the association between the side of symptom onset and prevalence of FoG in PD patients. Methods: We identified 57 patients who initially presented with one of the following symptom profiles: L-PD (n= 24), R-PD (n= 33). Asymmetry of motor symptoms was defined by the difference between rightand left-sided scores for lateralized items assessed by the Unified Parkinson’s Disease Rating Scale III and the patient’s report. Informed consents were obtained from patients before testing. In two groups, we recorded gender, age, disease duration. Global cognition status was assessed with Mini Mental State Examination. The overall severity of PD was assessed using the Hohen and Yahr (HY) stage during on state. Individuals were classified as those who experience freezing (FoG+), and those who do not experience freezing (FoG−) using UPDRS II (item from 14). Differences of demographic and clinical characteristics between LPD and RPD, the relation between prevalence of FoG and side of onset, were analyzed by paired t test and chi-square test as appropriate and significance level was set at p values of less than 0.05. Results: There were no difference in prevalence of FoG between L-PD and R-PD (p> 0.05, odds ratio 1.14, 95% CI 0.34 to 3.76). There were no differences between groups in gender, age, disease duration, cognition status, and HY stage (p> 0.05). Conclusion(s): In contrast to previous studies,which indicate relationship between difference of right and left brain activity and incidence rate of FoG, our findings suggest that side of onset is not associated with prevalence of FoG in PD. Further research is needed by reconsidering evaluation method and variable in order to reveal predictive factor. Implications:The result shows the necessity of additional research on variable of prediction factor for FoG, because these results on this study bring the valuable data to the field of rehabilitation.