Circadian Levels of Serum Melatonin and Cortisol in relation to Changes in Mood, Sleep, and Neurocognitive Performance, Spanning a Year of Residence in Antarctica
Table 6
Correlation of serum cortisol levels with clinical parameters, psychological tests, and neurocognitive performance during the polar summer and winter photoperiods.
S. No
Parameter/Test
Summer
Winter
Pearson’s correlation coefficient r
8 am
3 pm
8 pm
2 am
8 am
3 pm
8 pm
2 am
1
Age
−0.192
0.079
−0.139
−0.112
−0.305
0.316
−0.182
−0.254
2
Weight
0.242
−0.326
−0.218
0.125
0.203
0.015
−0.064
0.066
3
BMI
0.434
−0.123
−0.236
0.328
0.342
0.108
0.154
0.652
4
DASS 42
0.047
−0.126
−0.012
0.264
0.308
0.579*
0.184
0.438*
5
ESS
−0.864*
−0.042
0.053
0.036
−0.034
0.030
0.014
0.272
6
MEQ
−0.618
0.114
−0.346
−0.543*
−0.034
−0.169
0.031
0.912
7
MMSE
0.101
−0.346
−0.025
−0.584*
−0.102
0.595*
0.354
−0.001
8
Attention
Card sort test (correct response)
0.120
−0.025
−0.782*
−0.342
0.013
0.153
0.217
0.248
Digit span
−0.019
−0.879*
−0.145
0.312
−0.168*
0.336
0.085
0.058
Continuous performance test (target accuracy rate)
0.147
0.096
0.764
0.342
0.143
0.314
0.018
0.214
9
Executive function Stroop test (mean reaction time)
0.367
0.453
0.032
0.672
0.156
0.098
0.542
0.345
10
Visual motor ability FTT
0.519*
0.378
0.462
0.176
0.135
0.619
0.503
0.913
11
Visual memory
−0.045
0.147
0.134
0.439
0.400
−0.336
0.136
0.305
12
Arithmetic equations per minute
0.183
−0.025
0.156
0.283
0.050
0.054
0.148
0.177
13
Speed of processing mean simple RT
−0.519*
0.295
0.341
0.175
0.083
−0.349
0.053
0.065
Mean choice RT
0.321
0.346
0.145
0.467
−0.413
0.143
0.401
0.312
BMI: body mass index; FTT: finger tapping test; RT: reaction time. *Significant at .
