NCT04019522

American Heart Association- Stroke/Hypoxia Study

Completed NA Results posted Last updated 7 April 2026

What this trial tests

NA trial testing Acute Intermittent Hypoxia (AIH) in Stroke in 16 participants. Completed in 1 July 2025.

Timeline

15 July 2019

Primary endpoint
1 February 2022

1 July 2025

Quick facts

Lead sponsor	Shirley Ryan AbilityLab
Phase	NA
Status	Completed
Study type	INTERVENTIONAL
Allocation	na
Design	single group
Masking	none
Primary purpose	treatment
Enrollment	16
Start date	15 July 2019
Primary completion	1 February 2022
Estimated completion	1 July 2025
Sites	1 location across United States

Drugs / interventions tested

• Acute Intermittent Hypoxia (AIH) — full drug profile →

Conditions studied

• Stroke — all drugs for Stroke →

Sponsor

Shirley Ryan AbilityLab — full company profile →

Who can join

18 and older, any sex, with Stroke. Patients with the condition only — healthy volunteers not accepted.

Results — posted to ClinicalTrials.gov

Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.

Number of Participants With Adverse Events Primary · 6 days

All adverse events will be reviewed for safety and study continuation by the medical monitor.

Elevated blood pressure at baseline

Group	Value	95% CI
Hypoxia	1
Hypoxia	11

Heart Rate below 50 beats per minute at baseline

Group	Value	95% CI
Hypoxia	2
Hypoxia	10

Claustrophobia

Group	Value	95% CI
Hypoxia	1
Hypoxia	11

National Institute of Health Stroke Scale (NIHSS) Secondary · Baseline and Day 6

is a tool used by healthcare providers to objectively quantify the impairment caused by a stroke. The NIHSS is composed of 11 items, each of which scores a specific ability between a 0 and 4. For each item, a score of 0 typically indicates normal function in that specific ability, while a higher score is indicative of some level of impairment. The individual scores from each item are summed in order to calculate a patient's total NIHSS score ranging from 0-44. A change from baseline to follow up 1 (day 6) is reported, calculated from: value at day 6 - value at baseline

Group	Value	95% CI
Hypoxia	-0.3	± 1.9

Fugl- Meyer Assessment Secondary · Baseline, Day 6

Each test element will be graded on a 3-point ordinal scale and summed up to provide a maximum upper limb score of 66. Reliability and validity have been demonstrated. The FMA will be administered while the subject is seated. A score of 0 indicates no upper extremity function or reflexes, a score of 66 indicates complete control of the paretic upper extremity. The values reported are differences from follow up (Day 6) and baseline calculated as: value at day 6 - value at baseline

Group	Value	95% CI
Hypoxia	-1.6	± 4.7

Modified Ashworth Scale Secondary · Baseline, Day 6

This scale allows for characterization of increases in muscle tone, from low or normal tone to complete limb rigidity. Specifically, we will evaluate the elbow flexors, bilaterally. A score of zero indicates no residual muscle spasticity, a score of 4 is a completely rigid limb with no possible movement. Each participant had their stroke affected elbow joint tested. The values reported are differences from follow up (Day 6) and baseline calculated as: value at day 6 - value at baseline

Group	Value	95% CI
Hypoxia	-0.1	± 0.7

Grip Strength Secondary · Baseline, Day 6

A dynamometer measures maximum gross grasp (lb.) averaged over three attempts with each hand. The minimum possible value of zero lb. will be assigned when the participant cannot actively flex the fingers or grasp the dynamometer. Completed bilaterally, if possible The values reported are differences from follow up (Day 6) and baseline calculated as: value at day 6 - value at baseline

Affected Hand

Group	Value	95% CI
Hypoxia	4.38	± 7.6

Less Affected Hand

Group	Value	95% CI
Hypoxia	1.6	± 10.8

Pinch Strength Secondary · Baseline, Day 6

Hydraulic Handheld Dynamometer): A dynamometer measures maximum gross grasp (lb.) averaged over 3 attempts with each hand. The minimum possible value of zero lb. will be assigned when the participant cannot actively flex the fingers or grasp the dynamometer. The values reported are differences from follow up (Day 6) and baseline calculated as: value at day 6 - value at baseline

Affected Hand

Group	Value	95% CI
Hypoxia	1.7	± 3.5

Less Affected Hand

Group	Value	95% CI
Hypoxia	2.1	± 3.2

Elbow Strength Secondary · Baseline, Day 6

monitoring changes in isometric elbow flexion force using a dynamometer. A total of three trials will be taken on each side, with a rest break between trials. The average of the three trials will be recorded. Strength recorded in lbs, with a minimum value of zero. The values reported are differences from follow up (Day 6) and baseline calculated as: value at day 6 - value at baseline

Affected Arm

Group	Value	95% CI
Hypoxia	7.9	± 10.4

Less Affected Arm

Group	Value	95% CI
Hypoxia	8.3	± 14.4

D-KEFS Color-Word Interference Test Secondary · Baseline, Day 6

A neuropsychological measure that seeks to evaluate attention and inhibition. Subjects will be asked to read words or name ink colors as quickly as possible within a given time limit. The test supplies the examiner with three separate scores, including an ability to calculate an interference score. This final score allows for interpretation of cognitive flexibility, creativity and cognitive stress. This measure will be utilized to monitor subjects throughout their participation at specific time-points. Audio recording may be taken to ensure accurate recording of responses. The scale is from 1-

Group	Value	95% CI
Hypoxia	-0.1	± 1.9

5 Minute Neurological Test Secondary · Baseline, day 6

Quick short tests to assess clinical status performed by physician to ensure no change in neurologic status, The values reported are the count of participants who were found to have no change in neurolgical status from baseline to day 6 by the clinician

Group	Value	95% CI
Hypoxia	10

Adverse events — posted to ClinicalTrials.gov

Time frame: Adverse events were collected over the duration of intervention as well as at the single follow up which was within 1 week of interventions */8all occurred at 1 week or less**. Reporting threshold: 0%. Adverse-event reports describe events observed during the trial — not all are caused by the drug.

Hypoxia

Serious: 0/16 (0%)

Deaths: 0/16

Other adverse events (3 terms — click to expand)

Reaction	System	Hypoxia
Baseline Bradycardia	Cardiac disorders	—
Baseline Elevated Blood pressure	Cardiac disorders	—
Claustrophobia	General disorders	—

Data from ClinicalTrials.gov NCT04019522 adverse events section.

Sponsor's own description

Of the 795,000 people who experience a stroke every year in the US, only a small percentage will achieve full recovery. While current therapies promote strength and endurance, none directly address the unique potential of the brain to reorganize following injury. The goal of this project is to explore the effects of a novel therapy, acute intermittent hypoxia (AIH). During this therapy, individuals receive brief bouts of reduced oxygen levels by inhalation through a face mask. (This is akin to being on top of a tall mountain). In brief exposures, AIH is known to trigger the release of specific proteins that help the brain adapt to oxygen reductions. Published results in people with incomplete spinal cord injury have shown that AIH enhances muscle strength and coordination rather quickly. The research team aims to study the effects of AIH in stroke survivors.

Publications & conference data

1 peer-reviewed publication reference this trial (live from Europe PMC):

1. Acute Intermittent Hypoxia in People Living With Chronic Stroke: A Case Series.
   Pearcey GEP, Barry AJ, Sandhu MS, Carroll TJ, et al · · 2025 · cited 5× · PMID 39996325 · DOI 10.1161/strokeaha.124.046620