Akkomodation und Kognition:eine Frage der vegetativen Balance?

Der Ziliarmuskel und das Herz erfüllen unterschiedliche Aufgaben - werden aber beide über das vegetative Nervensystem gesteuert. Eine Steigerung der Herzrate bei einer leichten Leseaufgabe geht mit einer Verlagerung der Akkommodationsruhelage in die Nähe einher und die Akkommodation verlagert sich mit Zunahme der kognitiven Anforderung in die Ferne, während die Herzperiode abnimmt. Ursache ist eine Verschiebung in der vegetativen Balance. Ziel war es, die Akkommodationsveränderung dem Sympathikus bzw. Parasympathikus zu zuordnen. Es konnte allerdings keine signifikante Änderung der Akkommodation erneut gezeigt werden. Weder das "Lesen/Addieren" einer Zahlenmatrix noch ein "Lesen", "Addieren" und "Multiplizieren" mehrstelliger Zahlen führte zu einer Akkommodationsänderung. (Die Verhaltensdaten, Pupillengröße, Herzperiode sowie die Pulswellenlaufzeit zeigten eine Reaktion.) Geringe Akkommodationsänderungen gingen auf eine Blickrichtungsänderung und die Richtigkeit der Aufgabenbearbeitung zurück

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

<p>Abstract</p> <p>Background</p> <p>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.</p> <p>Results</p> <p>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.</p> <p>Conclusion</p> <p>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.</p