Non-invasive Treatment for Long COVID (Post COVID-19 Condition) Brain Fog

Pilot Study to Investigate Possible Non-invasive Treatment for Long COVID (Post COVID-19 Condition) Brain Fog

This study aims to assess the effects of both acute and chronic exposures to hypoxia and hypercapnia in patients with Long COVID syndrome.

Study Overview

• Status: Recruiting
• Conditions: Long COVID
• Intervention / Treatment: Other: Acute Placebo Visit; Other: Acute Progressive Carbon Dioxide; Other: Acute Intermittent Hypoxia; Other: Training: Placebo Control; Other: Training: Progressive Carbon Dioxide Ramping; Other: Training: Intermittent Hypoxic Exposure

• Study Type: Interventional
• Enrollment (Estimated): 45
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Jordan Parks; Phone Number: 480-301-6616; Email: parks.jordan@mayo.edu

Study Locations

• United States
  • Arizona
    • Scottsdale, Arizona, United States, 85259
      • Recruiting
      • Mayo Clinic in Arizona
      • Contact: Jordan Parks; Phone Number: 480-301-6616; Email: parks.jordan@mayo.edu
      • Principal Investigator: Courtney M Wheatley-Guy, PhD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion criteria:

• English speaking
• Diagnosis of Long COVID

Exclusion criteria:

• Any history of:

  • Coronary artery dissection or aortic dissection
  • Neurological disease (e.g. dementia, Alzheimer's disease, or other brain-related disease)
  • Cerebrovascular disease or stroke
  • Aneurysm

• If currently has:

  • Moderate-severe chronic obstructive pulmonary disease
  • Uncontrolled moderate-severe asthma
  • Moderate-severe bronchiectasis
  • Moderate-severe interstitial lung disease, requiring the use of supplemental oxygen
  • A necessity to use supplemental oxygen, for any reason
  • New or worsening symptoms (decompensation) of heart failure
  • Right heart disease due to chronic pulmonary disease/sleep apnea
  • Uncontrolled myocardial ischemia or angina
  • Uncontrolled heart arrhythmias
  • Heart or lung infection (e.g. myocarditis or pericarditis)
  • Left main coronary artery stenosis
  • Moderate-severe aortic stenosis
  • Pulmonary embolism, pulmonary infarction, or other blood clots
  • Severe respiratory disease
  • Chronic kidney disease
  • Chronic liver disease
• Females of childbearing potential will complete a urine pregnancy test at their baseline visit to rule out pregnancy
• BMI >40
• Study staff unable to obtain adequate signal for cerebral blood flow

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

8

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Acute exposure: Placebo, Progressive Carbon Dioxide, Intermittent Hypoxia; Study group will receive the three interventions in this order: Placebo, Progressive Carbon Dioxide, then Intermittent Hypoxia	Other: Acute Placebo Visit; The placebo visit will include 6 simulated cycles of 5 minutes breathing 21% oxygen from a douglas bag and 5 minutes breathing room air.; Other: Acute Progressive Carbon Dioxide; The progressive carbon dioxide visit will include a 60-minute progressive ramp which includes 6 cycles of progressive CO2 ramping starting at 0% and progressing up to 10% within 5 minutes immediately followed with 5 minutes of room air breathing in between cycles.; Other: Acute Intermittent Hypoxia; The intermittent hypoxia exposure visit will include 6 cycles breathing 8-12% oxygen (O2) for 5 minutes with a target pulse oximeter saturation of 86-90%, followed by 5 minutes of breathing room air.
Experimental: Acute exposure: Placebo, Intermittent Hypoxia, Progressive Carbon Dioxide; Study group will receive the three interventions in this order: Placebo, Intermittent Hypoxia, Progressive Carbon Dioxide	Other: Acute Placebo Visit; The placebo visit will include 6 simulated cycles of 5 minutes breathing 21% oxygen from a douglas bag and 5 minutes breathing room air.; Other: Acute Progressive Carbon Dioxide; The progressive carbon dioxide visit will include a 60-minute progressive ramp which includes 6 cycles of progressive CO2 ramping starting at 0% and progressing up to 10% within 5 minutes immediately followed with 5 minutes of room air breathing in between cycles.; Other: Acute Intermittent Hypoxia; The intermittent hypoxia exposure visit will include 6 cycles breathing 8-12% oxygen (O2) for 5 minutes with a target pulse oximeter saturation of 86-90%, followed by 5 minutes of breathing room air.
Experimental: Acute exposure: Intermittent Hypoxia, Placebo, Progressive Carbon Dioxide; Study group will receive the three interventions in this order: Intermittent Hypoxia, Placebo, Progressive Carbon Dioxide	Other: Acute Placebo Visit; The placebo visit will include 6 simulated cycles of 5 minutes breathing 21% oxygen from a douglas bag and 5 minutes breathing room air.; Other: Acute Progressive Carbon Dioxide; The progressive carbon dioxide visit will include a 60-minute progressive ramp which includes 6 cycles of progressive CO2 ramping starting at 0% and progressing up to 10% within 5 minutes immediately followed with 5 minutes of room air breathing in between cycles.; Other: Acute Intermittent Hypoxia; The intermittent hypoxia exposure visit will include 6 cycles breathing 8-12% oxygen (O2) for 5 minutes with a target pulse oximeter saturation of 86-90%, followed by 5 minutes of breathing room air.
Experimental: Acute exposure: Intermittent Hypoxia, Progressive Carbon Dioxide, Placebo; Study group will receive the three interventions in this order: Intermittent Hypoxia, Progressive Carbon Dioxide, Placebo	Other: Acute Placebo Visit; The placebo visit will include 6 simulated cycles of 5 minutes breathing 21% oxygen from a douglas bag and 5 minutes breathing room air.; Other: Acute Progressive Carbon Dioxide; The progressive carbon dioxide visit will include a 60-minute progressive ramp which includes 6 cycles of progressive CO2 ramping starting at 0% and progressing up to 10% within 5 minutes immediately followed with 5 minutes of room air breathing in between cycles.; Other: Acute Intermittent Hypoxia; The intermittent hypoxia exposure visit will include 6 cycles breathing 8-12% oxygen (O2) for 5 minutes with a target pulse oximeter saturation of 86-90%, followed by 5 minutes of breathing room air.
Experimental: Acute exposure: Progressive Carbon Dioxide, Placebo, Intermittent Hypoxia; Study group will receive the three interventions in this order: Progressive Carbon Dioxide, Placebo, Intermittent Hypoxia	Other: Acute Placebo Visit; The placebo visit will include 6 simulated cycles of 5 minutes breathing 21% oxygen from a douglas bag and 5 minutes breathing room air.; Other: Acute Progressive Carbon Dioxide; The progressive carbon dioxide visit will include a 60-minute progressive ramp which includes 6 cycles of progressive CO2 ramping starting at 0% and progressing up to 10% within 5 minutes immediately followed with 5 minutes of room air breathing in between cycles.; Other: Acute Intermittent Hypoxia; The intermittent hypoxia exposure visit will include 6 cycles breathing 8-12% oxygen (O2) for 5 minutes with a target pulse oximeter saturation of 86-90%, followed by 5 minutes of breathing room air.
Experimental: Acute exposure: Progressive Carbon Dioxide, Intermittent Hypoxia, Placebo; Study group will receive the three interventions in this order: Progressive Carbon Dioxide, Intermittent Hypoxia, Placebo	Other: Acute Placebo Visit; The placebo visit will include 6 simulated cycles of 5 minutes breathing 21% oxygen from a douglas bag and 5 minutes breathing room air.; Other: Acute Progressive Carbon Dioxide; The progressive carbon dioxide visit will include a 60-minute progressive ramp which includes 6 cycles of progressive CO2 ramping starting at 0% and progressing up to 10% within 5 minutes immediately followed with 5 minutes of room air breathing in between cycles.; Other: Acute Intermittent Hypoxia; The intermittent hypoxia exposure visit will include 6 cycles breathing 8-12% oxygen (O2) for 5 minutes with a target pulse oximeter saturation of 86-90%, followed by 5 minutes of breathing room air.
Placebo Comparator: Placebo Group; Study group will complete 6 simulated cycles of 5 minutes breathing 21% oxygen from a douglas bag and 5 minutes breathing room air (60 minutes) for every visit during the 14 days intervention period. Subjects will then return within 7 days of their final training visit to repeat baseline testing	Other: Training: Placebo Control; Intervention will consist of 6 to 10 study visits (3-5 sessions/week) to be completed within 14 days. Subjects will complete 6 simulated cycles of 5 minutes breathing 21% oxygen from a douglas bag and 5 minutes breathing room air (60 minutes) for every visit during the 14 days.
Experimental: Training Group; Training Study group will be complete 6 cycles of either progressive CO2 ramp protocol or the intermittent hypoxia protocol for 60 minutes for every visit during the 14 days. Subjects will then return within 7 days of their final training visit to repeat baseline testing	Other: Training: Progressive Carbon Dioxide Ramping; Intervention will consist of 6 to 10 study visits (3-5 sessions/week) to be completed within 14 days. Subjects will will be given the progressive CO2 ramp protocol of 60-minute sessions, which will include 6 cycles of progressive CO2 ramping starting at 0% and progressing up to 10% within 5 minutes immediately followed with 5 minutes of room air breathing in between cycles, for every visit during the 14 days.; Other: Training: Intermittent Hypoxic Exposure; Intervention will consist of 6 to 10 study visits (3-5 sessions/week) to be completed within 14 days. Subjects will will be given the intermittent hypoxia exposure protocol of 60-minute sessions, which will include 6 cycles breathing 8-12% oxygen (O2) for 5 minutes with a target pulse oximeter saturation of 86-90%, followed by 5 minutes of breathing room air for every visit during the 14 days.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in cerebral blood flow	The intracranial middle cerebral arteries will be obtained (MCAv) will be imaged with a linear probe and duplex ultrasound system to simultaneously measure CBFv by pulse wave doppler (peak and mean flow)	Baseline, post-acute exposure and 14 days post training
Change in heart rate variability	Short- term HRV analysis of a 3-lead ECG recording (5 minute recording) will evaluate both time-domain parameters (mean heart rate, standard deviation of normal-to-normal (NN) intervals (SDNN) and root mean square of successive differences between NN intervals rMSSD) and frequency-domain parameters (total power, high frequency (HF) and low frequency (LF) and LF/HF ratio).	Baseline, post-acute exposure and 14 days post training
Change in brain fog scale	Questionnaire assessing of how much brain fog is affecting daily abilities	Baseline, post-acute exposure and 14 days post training

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in fatigue functional assessment of chronic illness therapy-fatigue scale	Fatigue functional assessment of chronic illness therapy-fatigue scale (FACIT-Fatigue): assessment of how much fatigue is affecting daily abilities. Scores range from 0-52 for the FACIT with a higher score indicating higher levels of fatigue experienced.	Baseline, post-acute exposure and 14 days post training
Change in short form health survey (SF-36)	The Short Form (SF-36) Health Survey is a 36-item, participant-reported survey that measures patient health and disability. Possible scores range from 0 to 100, with 0 indicating maximum disability, and 100 indicating no disability.	Baseline, post-acute exposure and 14 days post training
Change in Trail making test	Trail making test: Consists of two parts. For part one, the subject will be presented with 25 numbered dots. The goal is to connect all 25 dots in numerical order quickly and accurately. The second part consists of 25 dots on the screen labelled with numbers and letters. The subject will then click the dots in sequential order by number followed by letter. For example, 1-A-2-B-3-C…, in the shortest amount of time possible while maintaining accuracy.	Baseline, post-acute exposure and 14 days post training
Change in rapid cognitive assessment tool (RCAT) score	The premise is to click spawning targets quickly and accurately. The assessment lasts one minute during which the game will add or reduce intensity based on real time performance. It is used to interpret psychological and psychomotor functions including hand-eye coordination, speed, response time, spatial awareness, situational awareness, and decision-making. Test takes one minute and score is calculate based on number of correct clicks.	Baseline, post-acute exposure and 14 days post training
Change in Task switching test performance	Task switching test will evaluate the individual's ability to switch between different tasks or operations. Participants are presented with a number between 1 and 9. The number will appear in one of two colors: purple or yellow. If the number is purple, the participant will answer with yes or no if the number is even. If yellow, the participants will answer with yes or no if the number is less than 5. Participants will see 40 numbers and their performance will be scored based on response time and accuracy.	Baseline, post-acute exposure and 14 days post training
Change in Rey Auditory Verbal Learning Test (AVLT) recall	Rey Auditory Verbal Learning Test (AVLT) will assess short term auditory recall. Subjects are read a list of 15 words and asked to repeat as many words as possible that they can remember back to the test administrator. They repeat this 5 times, then read a new list of 15 words to repeat back one time before returning to recall the first list of words.	Baseline, post-acute exposure and 14 days post training

Collaborators and Investigators

• Sponsor: Mayo Clinic
• Investigators: Principal Investigator: Courtney Wheatley-Guy, Mayo Clinic

Study record dates

Study Major Dates

• Study Start (Actual): September 24, 2024
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): December 1, 2026

Study Registration Dates

• First Submitted: September 24, 2024
• First Submitted That Met QC Criteria: September 24, 2024
• First Posted (Actual): September 26, 2024

Study Record Updates

• Last Update Posted (Actual): June 5, 2026
• Last Update Submitted That Met QC Criteria: June 3, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: fatigue; heart rate variability; brain blood flow; brain fog
• Additional Relevant MeSH Terms: Post-Infectious Disorders; COVID-19; Pathologic Processes; Chronic Disease; Disease Attributes; Behavioral Symptoms; Respiratory Tract Infections; Infections; RNA Virus Infections; Virus Diseases; Respiratory Tract Diseases; Lung Diseases; Pneumonia, Viral; Pneumonia; Coronavirus Infections; Coronaviridae Infections; Nidovirales Infections; Pathological Conditions, Signs and Symptoms; Behavior; Signs and Symptoms; Post-Acute COVID-19 Syndrome; Fatigue; Mental Fatigue
• Other Study ID Numbers: 24-006115

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