Brief potentially ictal rhythmic discharges

Criteria & assessment

• Focal (L/BI/UI/Mf) or generalized rhythmic activity >4 Hz, at least six waves at a regular rate, duration >=0.5 s and <10 s.
• Exclude known normal/benign patterns, activity forming part of burst-suppression/attenuation, and definite clinical correlates.
• Definite: evolution OR morphology AND location resembling interictal discharges or seizures in the same patient.
• Possible: sharply contoured without either definite criterion.
• Paroxysmal fast activity of the stated duration can qualify, focal or generalized, subject to the defining exclusions.