Enseñanza de la Biología en contexto

Table 3.13 shows correlations (Kendall’s tau) between T1-volumetric MRI

variables and scores on the Austin Maze and Test d2 for both shift workers and control participants.

Table 3.13: Correlations (Kendall’s tau) between T1-volumetric MRI and Austin Maze & Test

d2 for shift workers and control participants

Shift workers (n = 10) Control participants (n = 16) Austin Maze test d2 Austin Maze test d2

Time(s) Errors Correct Errors Time(s) Errors Correct Errors R hipp. TV .49* .45* .04 -.23 -.03 -.18 .37* -.08 R hipp. % TIV .27 .13 -.09 -.55* .18 .00 .15 .02

L hipp. TV .63* .67** -.09 -.09 -.40* -.38* .22 .05 L hipp. % TIV .31 .09 -.40 -.09 -.10 -.18 .07 .00 R temp. lobe TV .02 .33 .24 .07 -.25 -.17 .02 -.03 R temp. lobe % TIV -.16 .07 .42 -.20 .10 .08 -.20 .00

L temp. lobe TV -.16 .24 -.02 .34 -.42 -.33 -.02 .07 L temp. lobe % TIV -.29 .02 -.07 .16 -.17 -.18 -.20 .00

TIV .27 .58* .27 .18 -.59** -.37* .12 -.07

* = significant at .05 ** = significant at .01

L = left; R = right; hipp = hippocampus; temp. lobe = temporal lobe; TIV = total intracranial volume; TV = total volume

For shift workers, time taken on the Austin Maze to complete 10 trials was positively correlated with total right hippocampal volume, τ = .49, p (two-

tailed) < .05, and total left hippocampal volume, τ = .63, p (two-tailed) < .05.

Total errors made on the Austin Maze over 10 trials were positively correlated with total right hippocampal volume, τ = .45, p (two-tailed) < .05, total left

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= .58, p (two-tailed) < .05. For the Test d2, shift workers showed a significant

negative correlation between total errors made and right hippocampal percentage of intracranial volume τ = -.55, p (two-tailed) < .05.

For control participants, time taken on the Austin Maze was negatively correlated with total left hippocampal volume τ = -.40, p (two-tailed) < .05,

total left temporal lobe volume τ = -.42, p (two-tailed) < .05 and total

intracranial volume τ = -.59, p (two-tailed) < .01. Negative correlations were

also found between Austin Maze total errors and total left hippocampal volume τ = -.38, p (two-tailed) < .05 and total intracranial volume τ = -.36, p (two-

tailed) < .05. For the Test d2, control participants showed a significant positive correlation between total items correct and right hippocampal percentage of intracranial volume τ = .37, p (two-tailed) < .05.

Table 3.14 shows correlations between T1-volumetric MRI measures and WMS-III subtests for both shift workers and control participants. Total left hippocampal volume was negatively correlated with initial word list learning (WMS-III Word Lists 1) for shift workers, τ = -.53, p (two-tailed) < .05. For

control participants there were no significant correlations between WMS-III variables and T1-volumetric MRI variables.

Table 3.14: Correlations (Kendall’s tau) between T1-volumetric MRI and WMS-III subtests for

shift workers and control participants

Shift workers (n = 10) Control participants (n = 16) WMS-III Faces WMS-III

Word Lists WMS-III Faces

WMS-III Word Lists 1 2 1 2 1 2 1 2 R hipp. TV .03 .28 -.03 .17 .21 .15 .01 -.10 R hipp. % TIV .23 .14 .13 .02 .08 .11 -.13 -.08 L hipp. TV .28 .24 -.53* -.07 -.08 -.01 -.16 -.29 L hipp. % TIV .18 -.19 -.43 -.31 -.05 .04 -.27 -.22 R temp. lobe TV .03 .07 .10 -.05 .27 .13 .22 -.01 R temp. lobe % TIV .18 .02 .20 -.05 .14 .06 .10 .10 L temp. lobe TV -.43 -.26 .00 .47 .05 -.19 .08 -.17 L temp. lobe % TIV -.38 -.21 .15 .24 -.06 -.22 -.01 -.11

TIV -.13 .24 -.13 .17 .10 .13 .13 .03

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Table 3.15 shows correlations between T-1 volumetric MRI variables and performance on WAIS-III subtests for both shift workers (panel A) and control participants (panel B). Shift workers showed a negative correlation between Block Design scaled score and right hippocampal percentage of total intracranial volume, τ = -.73, p (two-tailed) < .05. For control participants, Digit

Span forward raw score was positively correlated with total volume of the right temporal lobe, τ = .42, p (two-tailed) < .05 and with total intracranial volume τ

= .42, p (two-tailed) < .05. Digit Span backward raw score was positively

correlated with total volume of the left temporal lobe τ = .46, p (two-tailed) <

.05 and with the left temporal lobe percentage of total intracranial volume, τ = .54, p (two-tailed) < .01.Digit Span scaled score was positively correlated with

total right temporal lobe volume, τ = .44, p (two-tailed) < .05, and total left

temporal lobe volume, τ = .50, p (two-tailed) < .05.

Table 3.15: Correlations (Kendall’s tau) between T1-volumetric MRI variables & WAIS-III

subtests for shift workers (panel A) and control participants (panel B) WAIS-III subtest scaled scores

A: Shift workers (n=10) BDesign Arithmetic Vocab DSpan F DSpan B DSpan R hipp. TV -.34 -.21 -.42 -.43 -.29 -.41 R hipp. % TIV -.73* .30 -.49 -.54 .03 -.30

L hipp. TV -.53 .22 -.59 -.55 -.09 -.41 L hipp. % TIV .35 .12 .00 -.10 .09 .01 R temp. lobe TV -.23 -.29 .03 .30 -.04 .12 R temp. lobe % TIV -.25 .00 -.02 .27 .28 .26 L temp. lobe TV -.28 .07 -.15 -.18 .01 -.20 L temp. lobe % TIV .46 -.08 .29 -.14 -.37 -.28

TIV .20 .16 .21 -.35 .25 .15 B: Control participants (n = 16) R hipp. TV .12 .10 .08 .15 .11 .20 R hipp. % TIV -.14 -.09 -.11 -.09 .01 -.04 L hipp. TV .25 -.07 .16 .30 .26 .38 L hipp. % TIV .04 -.24 -.09 -.13 .24 .10 R temp. lobe TV .21 .16 .21 .42* .28 .44*

R temp. lobe % TIV -.05 -.10 -.06 .01 .26 .14 L temp. lobe TV .37 -.03 .33 .32 .46* .50*

L temp. lobe % TIV .14 -.29 .13 .01 .54** .36

TIV .39 .21 .25 .42* .15 .32

* = significant at .05 ** = significant at .01

BDesign = Block Design; Vocab = Vocabulary; DSpan F = Digit Span forwards raw score; DSpan B = Digit Span backwards raw score; DSpan = Digit Span.

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The correlation coefficients of the two groups for cognitive variables versus T1 MRI variables were compared using the Fisher r-to-z transformation (see Table 3.16 for significant values; full r-to-z transformations in Appendix 6A). Shift workers showed a significantly stronger correlation than did control participants between time taken on the Austin Maze and total volume of the left hippocampus, z = 2.49, p (two-tailed) < .01, and total intracranial volume, z =

2.03, p (two-tailed) < .05. Shift workers’ correlations were also significantly

stronger between Austin Maze errors and the total volume of the left hippocampus, z = 2.61, p (two-tailed) < .01, and total intracranial volume, z =

2.25, p (two-tailed) < .05.

Table 3.16: Significant Fisher’s r-to-z-transformations for cognitive vs. MRI variable correlation coefficients for shift workers and control participants

Shift workers (n=10)

Control participants (n =16)

r z r z z-test p

Austin Maze time

L hipp. TV .63 0.74 -.40 -0.43 2.49 .01 TIV .27 0.28 -.59 -0.68 2.03 .04 Austin Maze errors L hipp. TV .67 0.82 -.38 -0.40 2.61 .01 TIV .58 0.67 -.37 -0.38 2.25 .02 WAIS-III BDesign L hipp. TV -.68 -0.84 .25 0.25 -2.33 .02 WAIS-III Vocab L hipp. TV -.75 -0.98 .16 0.16 -2.44 .01 WAIS-III DSpan F R hipp. TV -.73 -0.93 .15 0.15 -2.27 .02

BDesign = Block Design; Vocab = Vocabulary; DSpan F = Digit Span forwards raw score

Shift workers also had a significantly stronger relationship between total volume of the left hippocampus and WAIS-III Block Design, z = -2.33, p < .05,

and WAIS-II Vocabulary, z = -2.44, p = .01. Total volume of the right temporal

lobe was more significantly more strongly associated with WAIS-III Digit Span forward for shift workers compared to control participants, z = -2.27, p < .05.

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