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Ocular accommodation and cognitive demand: an additional indicator besides pupil size and cardiovascular measures?

Jainta S, Hoormann J, Jaschinski W - J Negat Results Biomed (2008)

Bottom Line: Heart period, pulse transit time, and the pupillary response were considered as reference for possible closed-loop accommodative effects.An observed decrease in accommodation could not be attributed to the cognitive demand itself for two reasons: (1) the cognitive demand induced a shift in gaze direction which, for methodological reasons, accounted for a substantial part of the observed accommodative changes. (2) Remaining effects disappeared when the correctness of task processing was taken into account.Although the expectation of accommodation as possible autonomic indicator of cognitive demand was not confirmed, the present results are informative for the field of applied psychophysiology noting that it seems not to be worthwhile to include closed-loop accommodation in future studies.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institut fuer Arbeitsphysiologie an der Universitaet Dortmund, Ardeystrasse 67, D-44139, Dortmund, Germany. jainta@ifado.de

ABSTRACT

Background: The aim of the present study was to assess accommodation as a possible indicator of changes in the autonomic balance caused by altered cognitive demand. Accounting for accommodative responses from a human factors perspective may be motivated by the interest of designing virtual image displays or by establishing an autonomic indicator that allows for remote measurement at the human eye. Heart period, pulse transit time, and the pupillary response were considered as reference for possible closed-loop accommodative effects. Cognitive demand was varied by presenting monocularly numbers at a viewing distance of 5 D (20 cm) which had to be read, added or multiplied; further, letters were presented in a "n-back" task.

Results: Cardiovascular parameters and pupil size indicated a change in autonomic balance, while error rates and reaction time confirmed the increased cognitive demand during task processing. An observed decrease in accommodation could not be attributed to the cognitive demand itself for two reasons: (1) the cognitive demand induced a shift in gaze direction which, for methodological reasons, accounted for a substantial part of the observed accommodative changes. (2) Remaining effects disappeared when the correctness of task processing was taken into account.

Conclusion: Although the expectation of accommodation as possible autonomic indicator of cognitive demand was not confirmed, the present results are informative for the field of applied psychophysiology noting that it seems not to be worthwhile to include closed-loop accommodation in future studies. From a human factors perspective, expected changes of accommodation due to cognitive demand are of minor importance for design specifications - of, for example, complex visual displays.

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Related in: MedlinePlus

Task presentations for experiment 3. The task layout for reading (a), adding (b) and multiplying periods (c), for comparison.
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Figure 4: Task presentations for experiment 3. The task layout for reading (a), adding (b) and multiplying periods (c), for comparison.

Mentions: Twenty subjects had to read, add or multiply a two-digit and a one-digit number; number combinations were identical for all three tasks and selected in order to avoid trivial combinations like "20*1". The arrangement of the numbers is shown in Figure 4; for reading the numbers, a "L" or "R" was placed between them and subjects had to react with the left or right mouse button, respectively (see Figure 4). During adding and multiplying periods, the presented result could be incorrect by ± 1 or ± 10; subjects had to quit the result as correct or false. Each number combination was presented for 2 s and the complete reading, adding or multiplying period lasted again 160 s.


Ocular accommodation and cognitive demand: an additional indicator besides pupil size and cardiovascular measures?

Jainta S, Hoormann J, Jaschinski W - J Negat Results Biomed (2008)

Task presentations for experiment 3. The task layout for reading (a), adding (b) and multiplying periods (c), for comparison.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2542343&req=5

Figure 4: Task presentations for experiment 3. The task layout for reading (a), adding (b) and multiplying periods (c), for comparison.
Mentions: Twenty subjects had to read, add or multiply a two-digit and a one-digit number; number combinations were identical for all three tasks and selected in order to avoid trivial combinations like "20*1". The arrangement of the numbers is shown in Figure 4; for reading the numbers, a "L" or "R" was placed between them and subjects had to react with the left or right mouse button, respectively (see Figure 4). During adding and multiplying periods, the presented result could be incorrect by ± 1 or ± 10; subjects had to quit the result as correct or false. Each number combination was presented for 2 s and the complete reading, adding or multiplying period lasted again 160 s.

Bottom Line: Heart period, pulse transit time, and the pupillary response were considered as reference for possible closed-loop accommodative effects.An observed decrease in accommodation could not be attributed to the cognitive demand itself for two reasons: (1) the cognitive demand induced a shift in gaze direction which, for methodological reasons, accounted for a substantial part of the observed accommodative changes. (2) Remaining effects disappeared when the correctness of task processing was taken into account.Although the expectation of accommodation as possible autonomic indicator of cognitive demand was not confirmed, the present results are informative for the field of applied psychophysiology noting that it seems not to be worthwhile to include closed-loop accommodation in future studies.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institut fuer Arbeitsphysiologie an der Universitaet Dortmund, Ardeystrasse 67, D-44139, Dortmund, Germany. jainta@ifado.de

ABSTRACT

Background: The aim of the present study was to assess accommodation as a possible indicator of changes in the autonomic balance caused by altered cognitive demand. Accounting for accommodative responses from a human factors perspective may be motivated by the interest of designing virtual image displays or by establishing an autonomic indicator that allows for remote measurement at the human eye. Heart period, pulse transit time, and the pupillary response were considered as reference for possible closed-loop accommodative effects. Cognitive demand was varied by presenting monocularly numbers at a viewing distance of 5 D (20 cm) which had to be read, added or multiplied; further, letters were presented in a "n-back" task.

Results: Cardiovascular parameters and pupil size indicated a change in autonomic balance, while error rates and reaction time confirmed the increased cognitive demand during task processing. An observed decrease in accommodation could not be attributed to the cognitive demand itself for two reasons: (1) the cognitive demand induced a shift in gaze direction which, for methodological reasons, accounted for a substantial part of the observed accommodative changes. (2) Remaining effects disappeared when the correctness of task processing was taken into account.

Conclusion: Although the expectation of accommodation as possible autonomic indicator of cognitive demand was not confirmed, the present results are informative for the field of applied psychophysiology noting that it seems not to be worthwhile to include closed-loop accommodation in future studies. From a human factors perspective, expected changes of accommodation due to cognitive demand are of minor importance for design specifications - of, for example, complex visual displays.

Show MeSH
Related in: MedlinePlus