Abstract
The ability of a blood vessel to change diameter in response to a change in carbon dioxide concentration is often referred to as vasomotor reactivity. This study aimed to determine whether vasomotor reactivity is impaired in patients with idiopathic Parkinson's Disease in comparison to healthy controls. Transcranial Doppler was used to measure cerebral blood flow velocity in the middle cerebral arteries at baseline and under hypocapnic conditions in 40 patients with idiopathic Parkinson's disease and 50 healthy controls. Vasomotor reactivity, assessed under hypocapnic conditions, is not impaired in patients with idiopathic Parkinson's Disease in comparison to healthy controls.
Highlights
Vasomotor reactivity (VMR) is the ability of cerebral blood flow (CBF) to change in response to changes in arterial partial pressure of CO2 (PaCO2) [1]
The current study aims to address three questions: (1) Is VMR impaired in patients with idiopathic Parkinson’s disease (IPD) in comparison to age-matched healthy controls (HC)? (2) Under hypocapnic conditions, do measures of Dynamic cerebral autoregulation (dCA): Cerebrovascular Resistance (CVR), Critical Closing Pressure (CrCP), Resistance Area Product (RAP) and Autoregulatory Index (ARI) show significant increases of the same magnitude, in both HC and IPD patients? (3) Does medication status (ON vs. OFF) affect either VMR or dCA measures under hypocapnic conditions?
This study demonstrates that dCA and measures of VMR, assessed under hypocapnic conditions, do not significantly differ between HC and patients with IPD, irrespective of medication status
Summary
Vasomotor reactivity (VMR) is the ability of cerebral blood flow (CBF) to change in response to changes in arterial partial pressure of CO2 (PaCO2) [1]. Hypocapnia induces cerebral vasoconstriction, whilst hypercapnia induces cerebral vasodilatation. Such changes in cerebral blood vessel diameter are largely determined by extracellular pH ([H+]) [2] but the autonomic nervous system has been implicated [3]. Dynamic cerebral autoregulation (dCA) refers to how spontaneous fluctuations in arterial blood pressure (ABP) can be measured alongside beat-to-beat measurement of CBF velocity (CBFV). Parameters that assess the integrity of dCA include Cerebrovascular Resistance (CVR), Critical Closing Pressure (CrCP), Resistance Area Product (RAP) [5] and Autoregulatory Index (ARI) [6]. DCA has been shown to improve in healthy subjects [7, 8]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
