Time delay of electroencephalogram index calculation: analysis of cerebral state, bispectral, and Narcotrend indices using perioperatively recorded electroencephalographic signals

R Zanner, S Pilge, E. F Kochs, M Kreuzer and G. Schneider

BJA: British Journal of Anaesthesia 103 ( 3 ): 394 - 399 , 2009