1. Differences between diving populations on psychometric tasks under simulated hyperbaric conditions
Sam Harding & Graham Samson

2. Overview
Introduce you to SCUBA Diving Research and the phenomenon of Nitrogen Narcosis
Methodology
Tests
Testing environment
Participants
Randomisation
Results
Discussion

3. Introduction
Increased atmospheric pressures – leads to nitrogen narcosis
Symptoms
Feels like being drunk
Impaired judgment & co-ordination
Fixation on problem solving strategies
Most research has used one ‘type’ of diver
Undergraduate
Navy
Commercial
Aim
Compare the effects of elevated pressure on two types of diver
Undergraduates
Recreational Sport Divers

4. Tests Manikin Task Wechsler Digit Symbol Test
10 versions of each test were used
No two people in a dive had same test set

5. Testing environment

6. Participants & Randomisation
N = One hundred and fourteen Undergraduate Divers (UG)
93 Males; Mean Age 20.9 years
N = Ninety three Recreational Sport Divers (RSD)
72 Males; Mean Age 36.7 years
Manikin Test 1st
Digit-symbol Test 1st
Surface Testing 1st
28/23
29/23
40m Testing 1st
29/24
Key: UG/RSD

7. Results 1 No effect of the order of presentation Depth Task
Significant effect of increased pressure
Both ‘types’ of diver (P≤0.05)
Both tasks (P≤0.01)
Significant difference between diver ‘types’

8. Results 2 Summary Manikin – UG significant better than RDS
Difference
Manikin 1 ATA
Mean No items completed
12.74
13.50
0.76
Mean No items correct
10.38
11.45
1.07*
Mean % items correct
79.55
84.18
4.63
Manikin 5 ATA
12.62
13.38
9.69
10.84
1.15*
74.64
80.84
6.20*
WDS 1 ATA
34.39
34.54
0.15
33.18
31.50
-1.68
96.23
91.65
-4.58***
WDS 5 ATA
35.24
33.27
-1.97
32.93
27.86
-5.07***
90.48
83.70
-6.78***
Key: ***=P<0.001,**=P<0.01, *=P<0.05
Summary
Manikin – UG significant better than RDS
Digit symbol – UG significantly worse than RDS

9. Therefore reduced task loading for the diver
Discussion
Weaknesses of the Methodology
Not the same environment as experienced when SCUBA diving
It is not dark
It is not cold
The diver is not wearing
Mask
Gloves
Breathing Regulators
Wet/Dry suit
The diver is not thinking about
Dive plan
Decompression schedule
Buoyancy control
Tasks to achieve during the task
Therefore reduced task loading for the diver

10. Therefore reduced task loading for the diver
Discussion
Strengths of the Methodology
Not the same environment as experienced when SCUBA diving
It is not dark
It is not cold
The diver is not wearing
Mask
Gloves
Breathing Regulators
Wet/Dry suit
The diver is not thinking about
Dive plan
Decompression schedule
Buoyancy control
Tasks to achieve during the task
Therefore reduced task loading for the diver

11. Discussion Ceiling effects were present in the Manikin task
Evidence of Nitrogen narcosis in both ‘types’ of divers
There are differences between the ‘types’ of divers
Conclusions drawn from previous research may not be applicable to today's recreational sport diver
Replication of previous work is needed to draw comparisons

12. Thank you & DDRC for their time and resources