Autonomic and cognitive functions in Parkinson's disease (PD).

We performed this study to evaluate the relationship between the stages of PD and autonomic dysfunction, and to find an association between the autonomic dysfunction and cognitive impairment in PD. Sixty-three patients who met the criteria of the United Kingdom PD Society Brain Bank were enrolled prospectively. Clinical stages were using the Hoehn and Yahr (H&Y) staging and unified PD rating scale motor scores.