Queston #9732Note

Understanding eye-related EEG artifacts will prevent one from incorrectly identifying them as epileptiform. The eye is a dipole; the cornea is positive while the retina is negative. When someone closes their eyes, the eyes will briefly look up leading to a positive (downward) deflection in the frontopolar leads (“Bell’s phenomenon”). When looking down, the positively charged cornea is farther away from the frontopolar leads, leading to a relative negative (upward) deflection in the frontopolar leads. Looking to the right will lead to the positive cornea of the right eye move toward F8. This causes a relative negative deflection in the Fp2-F8 channel. The left eye will move away from F7, causing a relative positive deflection in the Fp1-F7 channel. These findings are inversely true for looking to the left.