Measuring the effects of inert gas narcosis in divers with electroencephalogram (EEG)

Not Applicable

Recruiting

Conditions: gas narcosis
Anaesthesiology - Other anaesthesiology
Neurological - Studies of the normal brain and nervous system

Registration Number: ACTRN12622001049763

Lead Sponsor: niversity of Auckland

Brief Summary: Not available

Detailed Description: Not available

Recruitment & Eligibility

Status: Recruiting

Sex: All

Target Recruitment: 24

Inclusion Criteria

•Age between 18 and 55 years old
•Written informed consent
•Normal static binocular acuity, corrected or uncorrected
•Normal hearing
•Basic fluency in the English language
•Possession of a valid technical diving certificate
•Medical fitness for diving according to Recreational Scuba Training Council (RSTC) recreational diver standards.

Exclusion Criteria

A potential subject who meets any of the following criteria will be excluded from participation in this study:
•Current recreational drug use
•Use of psychoactive medication, including anti-histamines
•Mental illness
•Excessive alcohol use (>21 standard alcoholic drinks per week)
•Intake of caffeine-containing beverages over five glasses per day
•Smoker

After inclusion, a participant will be withdrawn from the study if:
•There is a deviation of the research protocol by the participant
•There is an intake of non-permitted medication
•There is an intake of alcohol 24 hours before the test
•There is an intake of caffeine-containing beverages during the test days
•Less than 6 hours of sleep during the night prior to the test day
•A dive made within 24 hours prior to an experiment involving hyperbaric exposure
•There are signs or symptoms of decompression illness
•They request to be withdrawn

Study & Design

Study Type: Interventional

Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
relative change in narcosis depth measured with a developed quantitative EEG measurement composite of both mutual information and global efficiency (functional connectivity analysis)[ baseline (before exposure) and for the duration of 10 minutes during exposure to the breathing gas mixture.]

Secondary Outcome Measures

Name	Time	Method
relative change in higher cognitive functions, measured with a psychometric test. <br><br>The Serial Sevens (S77) measures effect on comprehension of the information processing of the brain. Because both are higher cognitive functions they are more affected by gas narcosis. The tests will be performed on a specifically programmed dive computer. The test administration program stores the reaction time and errors made of each test for analysis. Baseline measurements will be regarded as 100% functioning. Subsequent measurements will be compared to this baseline measurement.[ baseline (before exposure) and for the duration of 5 minutes during exposure to the breathing gas gas mixture.]