Intermittent rhythmic delta activity

Intermittent Rhythmic Delta Activity (IRDA) is a type of brain wave abnormality found in electroencephalograms (EEG). It is found in the frontal (FIRDA) or occipital (OIRDA) areas of the brain and can be caused by a number of different reasons, some benign, unknown reasons, but also are commonly associated with lesions, tumors, and encephalopathies.