Tilt-table test during transcranial Doppler monitoring in Parkinson's disease

Cardiovascular autonomic dysfunction can occur in Parkinson's disease (PD) and intracranial vascular modifications following orthostatism may be relevant to diagnostic and therapeutic decision-making. We performed transcranial Doppler monitoring of right middle cerebral artery (MCA) at rest and during passive 70 degrees tilt in 19 patients with idiopathic PD and in 19 age-matched normal controls. Brachial arterial blood pressure (systolic, diastolic and mean), cardiac frequency (CF), respiratory frequency and mean velocity (MV) of the MCA were recorded after 10 min of rest in supine position, and each minute during 9 min of tilting and 5 min of restored clinostatic position. The pulsatility and cerebrovascular resistances (CVR) indexes were calculated. At rest there was no significant difference in blood pressure, CF, respiratory frequency and MCA mean velocity between patients and controls. During tilt test, PD patients showed a trend to higher pulsatility index values (p=0.09) and significant lower diastolic blood pressure (p=0.001), while there was no significant difference in CVR index. In conclusion, PD patients showed mild hypotensive response to orthostatic stress, with intracranial compensatory vasodilation. Our findings suggest a preserved intracerebral autoregulation in PD without symptoms of orthostatic intolerance.