Study of the Effects of Acute Exposure to Moderate Altitude Hypoxia on Prospective Memory. (HYPRO)

May 9, 2026 updated by: Direction Centrale du Service de Santé des Armées

Etude Des Effets d'Une Exposition aiguë à l'Hypoxie d'Altitude modérée Sur la mémoire Prospective (HYPRO)

The goal of this study is to investigate whether prospective memory, i.e., memory for delayed intentions, is impaired at moderate altitude (4,000m).

It will also allow to study the effect of air and oxygen administration during hypoxia exposure.

The main questions it aims to answer are:

  • Does moderate acute hypoxia impair prospective memory ?
  • If so, does air or oxygen adminsitration induce a restoration of prospective memory? Researchers will compare cognitive performance during normobaric hypoxia exposure to cognitive performance during normoxia (control situation).

Participants will:

  • Session S0. Perform a battery of neuropsychological tests and questionnaires). EEG will be recorded during tests. A cheek swab will be performed.
  • Sessions S1 and S2. Perform several cognitive tasks while exposed to hypoxia and to normoxia (2 different sessions, randomized order) in a normobaric chamber. These are standardized cognitive tests administered on a computer and cognitive tests embedded in a flight simulator scenario. Various questionnaires will be performed on a regular basis. Several physiological measurements will be performed continuously: EEG, ECG, SpO2 and breathing rate. Blood pressure will be measured at the beginning and at the end of hypoxia/normoxia exposure. A blood sample will also be performed. At last, participants will inhale air or oxygen through a mask while making a cognitive task in the chamber.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Flight crew operate in a dynamic, complex, and uncertain environment that requires them to process a large amount of information from multiple sources under time pressure. To successfully carry out their mission, flight crews must therefore constantly sort, prioritize, and analyze relevant information based on the situation, which requires them to manage their cognitive resources simultaneously-at the risk of experiencing a decline in performance that could significantly compromise aviation safety.

With recent changes in the geostrategic context, the flight profiles of operational missions expose military aircraft crews and onboard operators to a greater risk of in-flight hypoxia. During an acute hypoxic episode, physiological cardiac and respiratory responses are triggered to protect the body-and particularly the brain-from oxygen deprivation. However, these mechanisms are effective only for a limited time. If normoxia is not restored, symptoms will manifest as hypoxemia worsens.

Among flight crew members, impairments in cognitive functions-particularly prospective memory-such as failing to report one's position to other aircraft or failing to retract the flaps before takeoff, are common and can lead to serious accidents. To our knowledge, the effects of hypoxic exposure on this form of memory have not yet been investigated.

Study Type

Interventional

Enrollment (Estimated)

50

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.

Study Contact

Study Contact Backup

Study Locations

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

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Healthy volunteer
  • Has provided informed consent

Exclusion Criteria:

  • Individuals who do not understand French
  • Pregnant or breastfeeding women
  • Cardiovascular risk factor
  • Infectious disease within the last 4 weeks
  • Chronic cardiovascular, respiratory, hematological, neurological, psychiatric, or metabolic disease
  • History of epileptic seizures, convulsions, or loss of consciousness
  • Individuals with migraines
  • History of a bleeding disorder
  • History of high blood pressure
  • Current medication use (excluding contraception)
  • History of episodes of altitude intolerance
  • Stay at high altitude (> 3,500 m) within the last 3 months
  • Anxiety score on the Hospital Anxiety and Depression (HAD) scale > 7
  • Depression score on the HAD scale > 7
  • Uncontrollable claustrophobia or a history of panic attacks

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: Other
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Normoxia-Air + Hypoxia-Air
S1 = Normoxia exposure + air administration S2 = Hypoxia exposure + air administration
Other: Hypoxia exposure
Normobaric hypoxia exposure (FiO2 = 12,6%, equivalent to 4,000m) during 4h
Other: Air administration
Air administration (Fi02 = 21%) through a mask during 10 minutes
Behavioral: Standardized cognitive tests (on a computer)
Auditory oddball, visual oddball, event-based prospective memory, time-based prospective memory, n-back.
Device: Physiological measurements
EEG, ECG, SpO2, breathing rate, eyetracking, blood pressure
Biological: Blood sample
A blood sample is collected for mitochondrial breathing analyses
Behavioral: Cognitive tests embedded in a flight simulator scenario
Event-based prospective memory and time-based prospective memory. Prepar3D flight simulator.
Experimental: Hypoxia-Air + Normoxia-Air
S1 = Hypoxia exposure + air administration S2 = Normoxia exposure + air administration
Other: Hypoxia exposure
Normobaric hypoxia exposure (FiO2 = 12,6%, equivalent to 4,000m) during 4h
Other: Air administration
Air administration (Fi02 = 21%) through a mask during 10 minutes
Behavioral: Standardized cognitive tests (on a computer)
Auditory oddball, visual oddball, event-based prospective memory, time-based prospective memory, n-back.
Device: Physiological measurements
EEG, ECG, SpO2, breathing rate, eyetracking, blood pressure
Biological: Blood sample
A blood sample is collected for mitochondrial breathing analyses
Behavioral: Cognitive tests embedded in a flight simulator scenario
Event-based prospective memory and time-based prospective memory. Prepar3D flight simulator.
Experimental: Normoxia-O2 + Hypoxia-O2
S1 = Normoxia exposure + oxygen administration S2 = Hypoxia exposure + oxygen administration
Other: Hypoxia exposure
Normobaric hypoxia exposure (FiO2 = 12,6%, equivalent to 4,000m) during 4h
Behavioral: Standardized cognitive tests (on a computer)
Auditory oddball, visual oddball, event-based prospective memory, time-based prospective memory, n-back.
Device: Physiological measurements
EEG, ECG, SpO2, breathing rate, eyetracking, blood pressure
Biological: Blood sample
A blood sample is collected for mitochondrial breathing analyses
Behavioral: Cognitive tests embedded in a flight simulator scenario
Event-based prospective memory and time-based prospective memory. Prepar3D flight simulator.
Drug: Oxygen administration
Oxygen administration (FiO2 = 100%) through a mask during 10 minutes
Experimental: Hypoxia-O2 + Normoxia-O2
S1 = Hypoxia exposure + oxygen administration S2 = Normoxia exposure + oxygen administration
Other: Hypoxia exposure
Normobaric hypoxia exposure (FiO2 = 12,6%, equivalent to 4,000m) during 4h
Behavioral: Standardized cognitive tests (on a computer)
Auditory oddball, visual oddball, event-based prospective memory, time-based prospective memory, n-back.
Device: Physiological measurements
EEG, ECG, SpO2, breathing rate, eyetracking, blood pressure
Biological: Blood sample
A blood sample is collected for mitochondrial breathing analyses
Behavioral: Cognitive tests embedded in a flight simulator scenario
Event-based prospective memory and time-based prospective memory. Prepar3D flight simulator.
Drug: Oxygen administration
Oxygen administration (FiO2 = 100%) through a mask during 10 minutes

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in event-based prospective memory accuracy between hypoxia and normoxia conditions
Time Frame: Through study completion, an average of 1 month
Accuracy (%) = Prospective memory target detection rate (number of targets correctly responded to / total number of targets presented × 100)
Through study completion, an average of 1 month

Collaborators and Investigators

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

Sponsor

Direction Centrale du Service de Santé des Armées

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)

May 6, 2026

Primary Completion (Estimated)

December 31, 2026

Study Completion (Estimated)

December 31, 2026

Study Registration Dates

First Submitted

April 30, 2026

First Submitted That Met QC Criteria

May 9, 2026

First Posted (Actual)

May 13, 2026

Study Record Updates

Last Update Posted (Actual)

May 13, 2026

Last Update Submitted That Met QC Criteria

May 9, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2026-A00082-49 (Other Identifier: ANSM)

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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