The study of vasoreactivity of the cerebral vessels in patients with Parkinson disease

Background: The frequent orthostatic intolerance in PD could be the consequences of cardiovascular-autonomic failure and/or damaged cerebral autoregulation Objective: The purpose of this study is to evaluate cerebral vasoreactivity in patients with Parkinson disease and the potential influence of dopaminergic agents on it. Patients: Fifteen patients with Parkinson disease and 15 healthy controls were included in the study. Methods: Transcranial Doppler study was done to measure the mean velocities of the middle cerebral artery on either side at rest and after breath-holding to see the effect of hypercapnia on the blood velocities. This is done twice (once after the intake of antiparkinsonian drug and the other time 12 hours after the last dose) [group 2 and 1 respectively). Results: There was statistical significant difference between the patients (whether in group 1 or 2) and the control group regarding the breath holding index (P=0.003 and 0.022 respectively). While the difference between the 2 patient groups was not statistically significant (P=0.477). Conclusion: Patients with Parkinson disease have poor vasoreactivity of the cerebral vessels that may share in the pathogenesis of some symptoms. This is independent on the drug therapy.