2007, Piran, Slovenia

Environmental Ergonomics XII
Igor B. Mekjavic, Stelios N. Kounalakis & Nigel A.S. Taylor (Eds.), © BIOMED, Ljubljana 2007
that matched the previous sample pattern. Dependent measures included correct responses,
incorrect responses, time out errors, study time for the sample, and response time. The
delayed match-to-sample test consisted of 20 trials and required about 12 minutes to
complete.
Grammatical Reasoning. The Baddeley Grammatical Reasoning Test was an assessment of
language based reasoning. The test consisted of judging whether or not a series of
grammatical transformations presented in sentence form were true or false. The volunteer
completed as many answers as possible during a three-minute period. The number of items
attempted within the three-minute period and the percent correct were used as indices of
verbal reasoning ability. This test took approximately 4 minutes to complete.
Digit Symbol Substitution Test. This test measures coding ability and is a function of shortterm
memory. Volunteers were presented with a worksheet containing the numbers 1-9 and
an associated code symbol (e.g., X, =, -, etc). The worksheet consisted of a series of numbers
that needed to be coded. Each number had a blank box underneath in which to write the
appropriate code symbol. The volunteer completed as many symbol substitutions as possible
within a 90 second time period. The number of items attempted within the period and the
percent correct were used as indices of the ability to process codes rapidly and accurately.
This test took approximately 2-3 minutes to complete.
RESULTS
There were no differences in cognitive function due to the rate of core temperature cooling so
all trials were collapsed and responses analyzed with dependent t-tests (before immersion vs.
during immersion). The following significant findings were observed (Figures 1, 2, and 3).
These responses were similar whether cognitive performance was measured at 36.5°C or after
2 hours (Tre = 36.67°C, 8 trials).
Milliseconds
328
600
550
500
450
400
4-Choice Reaction Time
Before During
*
Figure 1. Four-choice reaction time before and during cold-water immersion. Asterisk
denotes significant difference (p = 0.008) between measurement times.