Episodic anterior drowsy theta in adults.

The present study included 1300 adults with various clinical problems. We prospectively studied the EEG's of this population over an 18-month period. Ninety-two patients showed episodic generalized or frontal-central bursts of theta activity, occurring synchronously over both hemispheres in drowsiness (episodic anterior drowsy theta or EADT). We found no interaction between the parameters involving the above theta rhythms (amplitude, rhythmicity, topography and presence or absence in the waking EEG), demographic variables (age, sex), and clinical presentation. Our data, however, did suggest that the incidence of the EADT may be higher in young females. We also found a tendency for the EADT in otherwise abnormal EEGs to be rhythmic and present awake. Our data indicated that the presence of EADT is non-specific as to etiology.