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. Cognitive functions were evaluated using the mini-mental state examination (MMSE) and the modified MMSE (3MS) test. The scale for outcome in PD-autonomic (SCOPA-AUT) was used to evaluate autonomic symptoms. Severities of autonomic dysfunction were classified using the composite autonomic scoring scale (CASS). Fifty-four of the 63 patients (86%) had shown abnormalities on CASS. H&Y stages correlated with SCOPA-AUT (p<0.05) and 3MS and MMSE scores (p<0.05). H&Y stages were positively related with autonomic dysfunction, heart rate ratios during deep breathing and the quantitative sudomotor axon reflex test (QSART) scores. Autonomic dysfunction may be present from disease onset, whereas the rate of cognitive decline increases with disease progression. We recommend that both qualitative and quantitative autonomic evaluation from the early stage of disease and regular cognitive screening with disease progression might be useful to facilitate optimal management in PD.