A Potential Role for Oxygen in the Development of Mental Fatigue and the Subsequent Decline in Cognitive Performance

Not Applicable

• Conditions: Near Infrared Spectroscopy; NIRS; Mental Fatigue; Hypoxia; Cognition; Cerebral Heamodynamics
• Interventions: Other: Hypoxia; Other: Normoxia

• Registration Number: NCT05100667
• Lead Sponsor: Vrije Universiteit Brussel

Brief Summary

Introduction Both Mental Fatigue (MF) and hypoxia impair multiple aspects of cognitive functioning. The decline in cognitive functioning in hypoxic conditions is associated with alterations in brain oxygenation and hemodynamic responses. These hemodynamic responses are preferably measured at the prefrontal cortex, an area of the brain that is known for its executive function and role in decision making, planning, attention and (short-term) memory. This study will investigate the role of prefrontal cortex oxygenation during the development of mental fatigue and during cognitive performances by altering the ambient oxygen availability through normobaric hypoxia (3800m; 12,9% O2) and normoxia.

Methods Subjects will perform four trials in a sound-insulated climate chamber (20°C and 40% RH). Upon entry in the climatic chamber participants will adapt to the environment for 30 minutes. Next, they will perform a modified cognitive test battery "cognition", a fine motor task "Motor Performance Series" and a visuomotor-fitlight task before and after a 60-minute individualized Stroop task or control task (randomized. blinded, placebo controlled, counter-balanced, cross-over design). Nearinfrared spectroscopy (NIRS) will be used to assess hemodynamic changes (oxygenated hemoglobin (O2Hb), deoxygenated-hemoglobin (HHb) and total hemoglobin (tHb)) at the PFC.

Hypotheses 1) MF will lead to earlier changes in the prefrontal NIRS-parameters (O2Hb, HHb, tHb) with lower oxygen availability. 2) The effects of MF on cognitive performance manifest itself to a greater extent with lower oxygen availability.3) Visuomotor performance declines to a greater extent due to MF with lower oxygen availability.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2021-01-28
• Study First Submitted QC: 2021-10-19
• Study First Posted: 2021-10-29
• Status Verified: 2022-04
• Last Update Submitted: 2022-04-27
• Last Update Posted: 2022-04-28
• Study Start: 2022-05-01
• Primary Completion: 2023-03-01
• Study Completion: 2024-01-01

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: All
• Target Recruitment: 15

Inclusion Criteria

• Healthy (No neurological or cardiovascular disorders)
• Male or female
• No medication
• Non-smoker
• Between 18 and 35 years old
• Recreational athlete population; performance level 2 or 3 for men according to De Pauw et al. (2013)[29] and performance level 2 or 3 for woman according to Decroix et al. (2015)
• Non-acclimatized to altitude (at least 2 months)

Exclusion Criteria

• Injuries
• Acclimated to altitude
• Use of medication
• Use of caffeine and heavy efforts 24 hours prior each trial
• Not eating a standardized meal, the morning of each trial

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Control MF	Normoxia	Emotionally neutral documentary
Control MF	Hypoxia	Emotionally neutral documentary
Mental fatigue	Normoxia	Stroop task
Mental fatigue	Hypoxia	Stroop task

Primary Outcome Measures

Name	Time	Method
Cerebral oxygenation	2 hours	Prefrontal cortex oxygenation = relative changes in oxy- and deoxy hemoglobin at the prefrontal cortex. During the whole frame, participants are equipped with a Near Infrared Spectroscopy device that measures cerebral oxygenation continuously at 10hz.
Mental fatigue	60 minutes	Results of a visual analogue scale for mental fatigue

Secondary Outcome Measures

Name	Time	Method
Fine motor control	5 minutes	Results of the vienna test system (MLS) =accuraccy and reaction time
Visuomotor control	7 minutes	Results of a visuomotor fitlight task = accuracy and reaction time
Cognition	20 minutes	Results of the Joggle cognition test battery (accuracy and reaction time

Trial Locations

Locations (1)

Human Physiology - MFYS; 🇧🇪 Brussels, Belgium