Background: Neurosurgical procedures that require a frontal approach could be an impediment for a successful Bispectral Index (R) (BIS (R)) frontal sensor placement. The aim of this study was to explore the utility of using the new BIS-Vista (TM) monitor (Aspect Medical Systems, Newton, MA) for occipital sensor placement in the patients undergoing brain neurosurgical procedures during propofol remifentanil anesthesia. Methods: Two BIS (R) Quatro sensors (Aspect Medical Systems, Newton, MA) mounted on the occipital and frontal regions were connected to two BIS-Vista (TM) monitors at three anesthesia states: before induction, during anesthesia maintenance, and recovery. Results: There were significant differences before induction (P = 0.0002) and at anesthesia maintenance (P = 0.0014) between mean +/- SD occipital (83.4 +/- 4.8, 66.7 +/- 7.2) and frontal (93.1 +/- 3.4, 56.9 +/- 9.1) BIS-Vista (TM) values. During anesthesia recovery, there was no difference (P = 0.7421) between occipital (54.6 +/- 9.3) and frontal (53.1 +/- 7.3) BIS-Vista (TM) values. Bland and Altman analysis revealed a BIS-Vista negative-bias (limits of agreement) of - 9.7 (+ 1.1, - 20.5) before anesthesia induction, + 9.8 positive-bias (+ 22.8, - 1.7) during anesthesia maintenance, and - 0.9 bias (+ 10.9, - 12.8) during anesthesia recovery. Conclusion: We demonstrated that not only the regional limits of agreement are too wide to allow data of the two montages to be used interchangeably but also the variation is a function of anesthetic depth. However, keeping in mind a relatively consistent BIS-Vista (TM) - 10 bias before induction and + 10 bias during anesthesia maintenance with limits of agreement of approximately +/- 11 BIS units, approximately double the clinically acceptable less than 10 BIS units level of agreement, BIS-Vista (TM) off-label occipital montage might be helpful in following a trend of propofol-remifentanil anesthesia in individual cases where frontal access is particularly difficult.