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Frontal intermittent rhythmic delta activity (EEG)

Frontal intermittent rhythmic delta activity (FIRDA) is shown as high amplitude, intermittent, 2 to 3 Hz semirhythmic activity that has anterior prominence. This pattern was once felt to be diagnostic of mid-line cerebral pathology, such as a third ventricle tumor, but is now recognized as a nonspecific indicator of encephalopathy (Schaul et al 1981). (Contributed by Dr. Jeffrey Nicholl and Dr. David Gloss.)