Effects of Blood Pressure on Cognition and Cerebral Hemodynamics in PD

April 21, 2026 updated by: Katie Longardner, University of California, San Diego

Effects of Blood Pressure on Cognition and Cerebral Hemodynamics in Parkinson's Disease

The goal of clinical trial is to learn about how blood pressure fluctuations affect cognitive performance (thinking abilities) and brain blood flow in persons with Parkinson's disease with and without orthostatic hypotension (low blood pressure when standing). The main questions it aims to answer are:

  • Is there a certain level of blood pressure that correlates with change in cognitive performance while upright?
  • Is there a certain level of change in brain blood flow that correlates with change in cognitive performance when upright?
  • How does cognitive performance differ between persons with Parkinson's disease that have orthostatic hypotension and those without orthostatic hypotension?
  • How does cognitive performance differ between the supine (laying down) and upright positions?
  • How do blood pressure and brain blood predict changes in cognitive performance over two years?

Participants in this study will undergo the following procedures:

  • Complete a screening visit with questionnaires, medical history, physical exam, and head-up tilt-table test.
  • Attend one baseline study visit, during which they will undergo a battery of computerized cognitive tests repeated twice: once while laying down and once while upright on a tilt table. Simultaneously, during the experiments we will measure blood pressure using a wrist-worn device and inflatable arm cuff and will measure brain blood flow using functional near-infrared spectroscopy (fNIRS), a non-invasive device that uses light sensors to detect changes in brain blood flow.
  • Attend one two-year follow-up visit, during which they will repeat a battery of computerized cognitive tests repeated twice: once while laying down and once while upright on a tilt table. During this visit, like before, we will measure blood pressure using a wrist-worn device and inflatable arm cuff and will measure brain blood flow using functional near-infrared spectroscopy (fNIRS).

Researchers will compare participants with Parkinson's disease with and without orthostatic hypotension in the laying down and upright positions to see if there are changes in thinking abilities between these groups.

Study Overview

Status

Withdrawn

Conditions

Intervention / Treatment

Detailed Description

Parkinson's disease (PD) is the second most common neurodegenerative disease worldwide and causes disabling non-motor symptoms that include cognitive impairment and low blood pressure (BP) on standing, called orthostatic hypotension (OH). About 30-50% of people with PD have OH; cognitive impairment is also common in PD and has several causes. OH is associated with cognitive impairment in PD, but it is unknown to what extent OH could be a treatable risk factor for cognitive decline. People with PD and OH can experience sudden temporary cognitive dysfunction when upright, suggesting that OH-related drops in BP can transiently reduce blood flow to the brain. In PD, OH also correlates strongly with long-term cognitive decline, predicting a 7-times higher risk of dementia. But it is unclear to what extent episodic cerebral hypoperfusion from OH - even if asymptomatic - contributes to ischemic brain damage that impacts long-term cognitive impairment in PD, which is a critical knowledge gap.

This project's objective is to determine how BP affects positional cognitive performance and brain blood flow in PD. We hypothesize that in person with PD patients with OH, but not those without OH, a critical threshold of cerebral hypoperfusion correlates with acute, temporary cognitive deficits when upright compared to supine and contributes to chronic cognitive decline.

The proposed experiments will close the existing knowledge gaps by determining the associations between BP and cerebral hemodynamics (brain blood flow) with cognitive performance. Experiments will be performed at baseline and repeated at two years. Sixty non-demented individuals with PD with OH (n=30) and without OH (n=30) will complete a computerized battery of cognitive tests in the supine and upright positions on a tilt table while undergoing simultaneous, non-invasive, continuous monitoring of BP and brain hemodynamics using functional near-infrared spectroscopy (fNIRS). Aim 1 will determine how BP relates to cognitive performance while supine and while upright. Aim 2 will use fNIRS to determine how cerebral hemodynamics (fNIRS) relate to cognitive performance and BP. Aim 3 will repeat the baseline assessments at a two-year follow-up visit to determine which BP and fNIRS measures are most associated with cognitive decline. We will compare these outcomes in participants with and without OH. This study will yield novel data about the short-term and long-term effects of low BP on cognitive performance and brain hemodynamics. Improving understanding of how BP affects cognition in PD will advance knowledge toward developing treatment targets to reverse, prevent, or delay OH-related cognitive impairment.

Study Type

Interventional

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Clinical diagnosis of idiopathic Parkinson's disease (PD) using the Movement Disorders Society (MDS) Clinical Diagnostic Criteria (Postuma, 2015)
  • Age least 50 years old
  • Hoehn & Yahr (H&Y) stages I to III (early to moderate stage PD)
  • Proficiency in the English language (native English speaker level)

Exclusion Criteria:

  • Any involuntary movements (i.e., tremor or dyskinesia) greater than 3 cm in amplitude, since the motion artifact can interfere with BP monitor cuff
  • Taking antihypertensive medications or alpha-adrenergic blocking medications since these can cause hypotension.
  • Dementia (including PD dementia (Emre, 2007) characterized by either Dementia Rating Scale 2 (DRS-2) score) 124 or less or clinical evidence of impaired instrumental activities of daily living
  • History of deep brain stimulation (DBS) surgery
  • Any unstable, active medical problem, e.g., decompensated heart failure, liver failure, etc.
  • Moderate or severe carotid artery stenosis (according to North American Symptomatic Carotid Endarterectomy Trial (NASCET) criteria (Ferguson, 1999)
  • History of cerebral infarction or hemorrhage
  • Uncontrolled diabetes or any other systemic disease that causes autonomic failure
  • Any terminal illness with life expectancy less than 2 years
  • Illiteracy
  • Impairment of hearing or vision that is not corrected by devices (e.g., hearing aids or glasses)
  • Currently pregnant (will be confirmed with a urine pregnancy screening test in people of child-bearing potential)
  • Any other condition, which, in the opinion of the investigator, could place the participant at increased risk (e.g., substance abuse)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Diagnostic
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Supine cognitive testing first
Participants will undergo a computerized cognitive battery in the supine position, followed by a similar battery with alternate test versions in the upright position while on a head-up tilt table.
Diagnostic test: Head-up tilt table
Different versions of cognitive assessments will be administered in the supine and upright positions while the participant is on the tilt table.
Experimental: Upright cognitive testing first
Participants will undergo a computerized cognitive battery in the upright position, followed by a similar battery with alternate test versions in the supine position while on a head-up tilt table.
Diagnostic test: Head-up tilt table
Different versions of cognitive assessments will be administered in the supine and upright positions while the participant is on the tilt table.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Verbal fluency score (number of words generated in one minute)
Time Frame: 24 months
Participant names as many words from a prompt as possible in one minute. Minimum: 0; Maximum: N/A; higher is better
24 months
Blood pressure (mmHg)
Time Frame: 24 months
Participants' blood pressure will be measured during the visit.
24 months
Oxygenated hemoblobin change from baseline
Time Frame: 24 months
Functional near-infrared spectroscopy will measure relative changes in oxygenated hemoglobin during cognitive testing.
24 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of California, San Diego

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

August 15, 2025

Primary Completion (Estimated)

June 1, 2029

Study Completion (Estimated)

August 31, 2029

Study Registration Dates

First Submitted

February 1, 2024

First Submitted That Met QC Criteria

February 1, 2024

First Posted (Actual)

February 9, 2024

Study Record Updates

Last Update Posted (Actual)

April 27, 2026

Last Update Submitted That Met QC Criteria

April 21, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 210738a

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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