Visual evoked potentials with CRT and LCD monitors: when newer is not better.
BACKGROUND
The stimulus for pattern reversal visual evoked potentials (PRVEP) has traditionally been delivered by a cathode ray tube (CRT) monitor. Liquid crystal display (LCD) monitors have become more affordable and are being used instead of CRT monitors for many applications. We tested the hypothesis that LCD monitors were equivalent to CRT monitors when used for PRVEP.


METHODS
Monocular, full field PRVEP with a 32' check size were obtained in six normal subjects with a CRT monitor and LCD monitors having 2 msec, 8 msec, and 30 msec response times. The average P100 latency with the CRT screen was compared to the latencies with the LCD screens.


RESULTS
The mean P100 latency of the CRT monitor was 107.7 (+/-6.6) ms, for the LCD 2 msec monitor was 115.7 (+/-6.9; p < 0.0001) ms, for the LCD 8 msec monitor was 118.5 (+/-6.5; p < 0.0001) ms, and the LCD 30 msec monitor was 156.8 (+/-6.8; p < 0.0001) ms.


CONCLUSIONS
Currently available liquid crystal display (LCD) monitors do not provide data comparable to cathode ray tube (CRT) monitors. LCD monitors cannot replace CRT monitors for pattern reversal visual evoked potentials unless new normative data are obtained.
Husain
Aatif M
AM
Department of Medicine (Neurology), Duke University Medical Center and Neurodiagnostic Center, Veterans Affairs Medical Center, Durham, NC 27710, USA. Aatif.husain@duke.edu
Hayes
Susan
S
Young
Margaret
M
Shah
Dharmen
D
D000328:Adult; D001931:Brain Mapping / Q000295:instrumentation* / Q000379:methods; D003201:Computers / Q000191:economics / Q000592:standards; D003626:Data Display / Q000191:economics / Q000592:standards*; D004569:Electroencephalography / Q000191:economics / Q000295:instrumentation* / Q000379:methods; D004582:Electronics, Medical / Q000295:instrumentation* / Q000379:methods; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D050866:Liquid Crystals / Q000592:standards; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation; D011237:Predictive Value of Tests; D011930:Reaction Time / Q000502:physiology; D013997:Time Factors; D014584:User-Computer Interface; D014793:Visual Cortex / Q000502:physiology