Measuring Cognitive Enhancement During Hyperbaric Oxygen Treatments

The aim of the current study was to examine the effect of short-term HBOT on a range of cognitive abilities. The current study examined whether there is a HBOT-related short-term cognitive improvement and, if so, what specific cognitive abilities are improved by the intervention.

Participants were recruited through ads on the internet and on student social groups. All participants underwent a comprehensive physical and neurological examination, and general medical conditions were ruled out. Participants were excluded if reported changes in their cognitive or behavioral functions during one month prior to the beginning of the study. Smokers (people who smoke more than seven cigarettes a week) were required to take a lung x-ray confirming there isn't a pulmonary pathology, such as pneumothorax, pulmonary bullae, emphysema, or other lung pathologies preventing them from staying in a high ATA environment. Participants with an abnormal x-ray were excluded from the study. Participants who regularly use Methylphenidate (i.e. Ritalin) or other stimulants for attention disorders (i.e. ADHD) were instructed not to take it at the day of the experiment.

Following consent, all the participants were exposed to the testing battery in a group setting. One of the experimenters went through each of the sub-tests instructions in a detailed manner prior to a practice phase in which participants trained on the tasks. Afterwards, participants were randomized to perform the tasks in one of two chambers with two different clinical environments: (a) HBOT condition: (2 ATA 100% oxygen for 90 minutes). The atmospheric pressure in this condition was set to 2 ATA. This ATA level is known to have a clinical effect, whereas higher-pressure levels may result in inhibitory brain effects or even lead to focal toxicity (Efrati and Ben-Jacob, 2014). (b) Control condition: in which the chamber was not pressurized (Normobaric condition- 1 ATA for 90 minutes) and participants breathed air (21% oxygen). In this condition, ATA was elevated for a few minutes to 1.2 ATA in order to mimic the feeling of pressure building up in the ears. The pressure was decreased soon after to 1 ATA.

The assessment began 30 min after participants wore the oxygen masks within the chamber, in order to enable appropriate brain oxygenation in the HBOT condition (Vadas et al., 2017). The battery was composed of cognitive tests adapted for high functioning subjects and adjusted to an in-chamber group administration setting.