Pattern visual evoked potentials elicited by organic electroluminescence screen.

Celso Soiti Matsumoto,Kei Shinoda,Takeshi Iwata,Haruka Minoda,Kakeru Sasaki,Harue Matsumoto,Hideaki Funada,Atsushi Mizota

doi:10.1155/2014/606951

Abstract

Purpose. To determine whether organic electroluminescence (OLED) screens can be used as visual stimulators to elicit pattern-reversal visual evoked potentials (p-VEPs). Method. Checkerboard patterns were generated on a conventional cathode-ray tube (S710, Compaq Computer Co., USA) screen and on an OLED (17 inches, 320 × 230 mm, PVM-1741, Sony, Tokyo, Japan) screen. The time course of the luminance changes of each monitor was measured with a photodiode. The p-VEPs elicited by these two screens were recorded from 15 eyes of 9 healthy volunteers (22.0 ± 0.8 years). Results. The OLED screen had a constant time delay from the onset of the trigger signal to the start of the luminescence change. The delay during the reversal phase from black to white for the pattern was 1.0 msec on the cathode-ray tube (CRT) screen and 0.5 msec on the OLED screen. No significant differences in the amplitudes of P100 and the implicit times of N75 and P100 were observed in the p-VEPs elicited by the CRT and the OLED screens. Conclusion. The OLED screen can be used as a visual stimulator to elicit p-VEPs; however the time delay and the specific properties in the luminance change must be taken into account.

Highlights

Cathode-ray tube (CRT) monitors have been used as visual stimulators to elicit pattern-reversal visual evoked potentials (p-VEPs)
The p-VEPs elicited by liquid crystal displays (LCD) screens have longer implicit times than those elicited by CRT screens due to several factors such as the total temporal differences between the LCD’s electronic input and radiometric output signals, caused by the response time and the input lag, and the flash effect [4,5,6,7]
A burst of pulses at 60 Hz was delivered to the CRT monitor and a square wave pulse was delivered to the OLED screen to change the luminance of the checks

Summary

Introduction

Cathode-ray tube (CRT) monitors have been used as visual stimulators to elicit pattern-reversal visual evoked potentials (p-VEPs). CRT has become less available in the market As it has been extensively replaced by liquid crystal displays (LCD) as a television monitor and computer monitor, one might imagine that LCD may be good replacement for CRT as a visual stimulator for pVEPs. But LCDs have an inherent problem as visual stimulators because they take several milliseconds for the crystal molecules to change their alignment to permit the light to pass through the polarizing filter of the LCD [1, 2] (http://www.sharp.co.jp/products/lcd/tech/s2 1.html). Because the properties of the luminance changes vary for individual LCD screens, this may restrict the use of LCD screens as a general standard visual stimulator to elicit pVEPs

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Conclusion