Demographic, clinical and sway parameters.

Data are presented with the mean and standard deviation. P-values were assessed by ANOVA with post-hoc Student's t test, or with the Pearson test.#p†pap, anteroposterior; BDI, Beck's Depression Inventory; BMI, Body Mass Index; ECF, eyes closed with foam; ml, mediolateral; MMSE, Mini Mental State Examination; RMS, root mean square of sway; SN hyperechogenicity, mean area of hyperechogenicity of the substantia nigra; UPDRS III, motor part of the Unified Parkinson's disease Rating Scale.