Memory Load and Display Polarity in Visual Search Performance and EEG Response

Abstract

Electroencephalogram measures have frequently been shown to be highly sensitive to variations in task conditions; however, research on the effects of memory load on EEG response and Visual Display Terminal (VDT) performance is lacking. Data from 19 college students were analyzed for effects of memory load and polarity on VDT performance. Included also were modulation of the EEG distribution around the cerebrum, the inferred source of operation of working memory and comprehension. Analyses indicated that the effects of memory load on finish time were statistically significant. The theta band at FP1 and FP2 had larger change in power than at T6, showing a large effect between memory load and frontal lobe function. This experiment on polarity and EEG response indicated the power change in the theta band was stronger for positive contrast than negative; however, the polarity of the display had no statistically significant effect on EEG response.

Evaluating the Effectiveness of Using Electroencephalogram Power Indices to Measure Visual Fatigue

“…Thus, visual fatigue may not be assessed adequately using only a single criterion (Saito, 1999). The commonly used visual fatigue evaluation indices include critical-flicker fusion (Lin, Chen, Lu, & Lin, 2008;Chan & Hsu, 2010), near-point accommodation (Yano, Emoto, & Mitsuhashi, 2004;Krupinski & Reiner, 2012), visual-evoked potential (Murata, Araki, Yokoyama, Yamashita, Okumatsu, & Sakou, 1996;Emoto, Niida, & Okana, 2005), eye-fixation-related brain potential (Yagi, Ikoma, & Kikuchi, 2009), eye blink (Philipp, Udo, & Peter, 2003), and subjective rating of visual fatigue (Kuze & Ukai, 2008). Each of these visual fatigue indices has its own unique physiological or psychological basis.…”

Frontal Midline Theta Rhythm: Comment on Chan and Hsu (2010)

“…In the experiment by Chan and Hsu (2010), participants performed relatively better when 3-and 5-character memory loads were used. Overload of working memory might have occurred when the number of Chinese characters exceeded 9.…”

“…The purpose of the experiment by Chan and Hsu (2010) was to investigate whether working memory is reduced in a task using a visual display terminal (VDT). The authors examined behavioral performance and EEG changes associated with memory load in a visual-search task using a VDT.…”