What it looks like
Runs of rhythmic activity faster than 4 Hz, lasting 0.5 to under 10 seconds (at least six waves at a regular rate), that are not a known normal pattern or benign variant and have no clinical correlate. 1
What it means at the bedside
"Definite" BIRDs either evolve or match the patient's own interictal discharges or seizures in shape and place. They mark cortex that is likely to produce seizures; they are a reason to keep monitoring, and often to look for the seizure onset zone.