Electric activity produced by eye flutter simulating frontal electroencephalographic rhythms.

Abstract A rhythm sometimes having the spurious appearance of alpha activity and associated with flutter of the eyelids occasionally is observed in records taken from the frontal and temporal leads of the electroencephalogram of normal persons and patients and is commonly seen when recordings are made from electrodes near the eyes. This rhythm is usually inhibited when the eyes are open and can be inhibited by holding the closed eyelids motionless. The rhythm is often increased briefly during mental activity. When recorded from electrodes placed close to the eyes, the rhythm was present in 8 of 14 normal persons used as controls and it appeared in 3 of 100 consecutive routine electroencephalograms. The rhythm is thought to be extracerebral in origin, probably resulting from oscillation of the electric field of the eyes produced by rapid ocular movements associated with flutter of the eyelids. It is suggested that flutter of the eyelids may be the source of kappa electroencephalographic waves.