Sudomotor and cardiovascular autonomic function in de novo Parkinson's disease assessed by sudoscan and cardiovascular reflexes

Objective: The prevalence of autonomic involvement in early stage of Parkinson 's disease (PD) is still debated. Aim of this study is to assess the autonomic functions in de novo PD patients (dnPD) in comparison with PD patients on therapy (PDot) and healthy controls (HC). Methods: Twenty-eight dnPD and 24 PDot, to whom Unified Parkinson's Rating Scale (UPDRS) was administered, and 23 HC underwent electrochemical skin conductance (ESC) measured with sudoscan, cardiovascular reflexes (head-up tilt test HUTT, Valsalva maneuver, deep breathing, hand grip, and cold face),and Scales for Outcomes in Parkinson's Disease-Autonomic Dysfunction (SCOPA-AUT) questionnaire. Results: The mean SCOPA-AUT total score was significantly higher in dnPD group compared with HC group (p < 0.001) and significantly lower than PDot (p = 0.004). No significant difference of ESC mean values were found between dnPD and HC group. DnPD had a significantly lower diastolic blood pressure (BP) response at handgrip test (p = 0.005) compared with HC. Hands and feet ESC significantly negatively correlated with disease duration (p = 0.014; p = 0.025) and feet ESC significantly negatively correlated with UPDRS III (p = 0.039). Systolic and diastolic BP responses at 3rd minute of HUTT correlated significantly negatively with disease duration (p < 0.001; p = 0.003) and with UPDRSIII (p = 0.001; p < 0.001). BP response to Valsalva maneuver negatively correlated with UPDRSIII (p = 0.006). Conclusion: Although dnPD patients complain of thermoregulatory symptoms, we found no alteration in the sudomotor function investigated with sudoscan. Furthermore, a deficit of the sympathetic vasoconstrictive response to the isometric exercise was detected, suggesting an early involvement of the autonomic cardiovascular components in dnPD.