Clinical correlation of occipital intermittent rhythmic delta activity

Frontal intermittent rhythmic delta activity is associated with encephalopathy, and temporal intermittent delta activity is associated with epilepsy, but the importance of OIRDA (OIRDA) is less well defined. The authors reviewed retrospectively EEGs and medical records of 77 patients with OIRDA to determine whether they had epilepsy, acute encephalopathy, or another diagnosis. They compared the incidence of epilepsy in this population with a control group of 77 patients referred for EEG, matched for age, gender, and year of EEG. OIRDA was most commonly generalized, high amplitude, saw toothed, and reactive to eye opening, and with mean frequency of 2.89 +/- 0.50 Hz. Mean age was 8.1 +/- 4.5 years. Seventy-six of 77 patients were