Overall correlation between the bispectral and the patient state indices was 0.667, 0.671 in Group 1, 0.650 in Group 2 and 0.675 in Group 3 (P<0.01). For values of the bispectral index between 45 and 60, only 40% of corresponding patient state index values were between 25 and 50. For patient state index values of 25-50, only 50% of the corresponding bispectral index values were in the range of 45-60.