Difference of static postural balance in patients with Parkinson's Disease and scans without evidencec of dopaminergic deficits

Abstract

Differentiating scans without evidence of dopaminergic deficit (SWEDD) from Parkinson's disease (PD) is very important to avoid costly and inappropriate interventions. Little is known of postural balance strategy of SWEDD patients. The purpose of this study was investigate difference of static postural balance between SWEDD and PD patients. Eleven patients with SWEDD, 11 patients with PD and normal subjects were instructed to quietly stand on a force plate in a comfortable self selected stance width. Center of pressure (COP) was measured for quantitative evaluation during static standing. As outcome measure, mean distance, mean velocity, 95% confidence ellipse area, mean frequency, peak frequency and peak power were derived from the COP time series in overall, anterio-posterior (AP) and medio-lateral (ML) directions. ANOVA and post hoc test were evaluated for comparison between SWEDD patients and PD patients. SWEDD patients presented a smaller postural sway size and a more frequent postural sway manly in ML direction (p< 0.05). In contrast, there was no significant differences in mean velocity and peak power (p>0.05). There were no significant difference between SWEDD patients and normal subjects (p>0.05). These results indicate that some COP-based outcome variables might be useful to distinguish SWEDD patients with PD patients. This study suggests that static postural balance test could aid clinicians in the identification of potential SWEDD.