Neonatal rhythmic and periodic patterns of uncertain significance

Criteria & assessment

• Periodic discharges have relatively uniform morphology/duration, a measurable interdischarge interval, and near-regular recurrence: cycle length varies <50% between adjacent cycles in >50% of cycle pairs.
• A discharge has <=3 phases or lasts <=0.5 seconds regardless of phases; a burst lasts >0.5 seconds and has >=4 phases.
• RDA repeats relatively uniform waveforms without an inter-wave interval and has cycle-length variation <50% in >50% of adjacent cycle pairs.
• PD or RDA must persist for >=6 cycles.
• Location is lateralized, diffuse with asynchronous all-electrode involvement, bilateral independent, or multifocal; report onset focus, maximal spread, and F/C/T/O/Z or hemispheric predominance as applicable.
• For diffuse patterns, frontal, occipital, or midline predominance requires amplitude >=50% greater than the comparison region in an appropriate referential montage.