Blood Pressure Effects on Cognition and Brain Blood Flow in PD

Parkinson's disease (PD) is the second most common neurodegenerative disorder worldwide. Besides causing symptoms that impair movement, PD also causes non-motor symptoms, such as problems thinking and orthostatic hypotension (OH), i.e., low blood pressure (BP) when standing. About one-third of people with PD have OH, which can cause sudden, temporary symptoms while upright, including lightheadedness, dizziness, and fainting. People with PD and OH can also experience problems thinking that happen only while upright and not while sitting - this can occur without other symptoms, such as feeling dizzy or faint. However, the level of low BP that can affect thinking remains unknown, and no guidelines exist for treating OH when it happens without symptoms. This is significant because OH could be a treatable risk factor for thinking problems in PD, but OH is often not treated if people do not report obvious symptoms. This project's goal is to determine how BP affects brain function in PD. The proposed experiments will measure BP and brain blood flow continuously in real-time using innovative wearable technology. Persons with PD with OH and without OH will undergo repeated cognitive tests while supine (lying down) and while upright. I will study the associations between BP, thinking abilities, and brain blood flow, and will compare groups with and without OH. These findings could be important because if a certain level of BP correlates with thinking abilities, then treating OH in PD may prevent thinking problems, which would improve health-related quality of life and reduce disability and healthcare costs.