Patent ID: 8577440

Claim:
A bispectral index sensor comprising: an elongated substrate having: a first end portion and a second end portion and having a first electrode disposed on the first end portion and a second electrode disposed on the second end portion, the first electrode and the second electrode being separated from one another by a distance substantially equal to a distance from a patient's temple to a central portion of a patient's forehead, such that the first electrode is adapted to be placed on a patient's temple and the second electrode is adapted to be placed on the central portion of the patient's forehead; a third electrode and a fourth electrode disposed on the substrate in spaced apart relation between the first electrode and the second electrode, wherein the third electrode is positioned on the substrate to be placed on the patient's forehead directly above the patient's eye when the first electrode is placed on the patient's temple and the second electrode is placed on the central portion of the patient's forehead, the fourth electrode being positioned on the substrate between the second electrode and the third electrode and being adapted to be placed on the patient's forehead between the second electrode and the third electrode; wherein the elongated substrate has a width and a thickness, and wherein the substrate is sufficiently rigid in a direction along the width to prevent the electrodes from moving laterally relative to a longitudinal axis of the sensor and being sufficiently flexible along the thickness to facilitate bending of the substrate about a patient's head when the first electrode is placed on the patient's temple and the second electrode is placed on the central portion of the patient's forehead.