Plus modifier and extreme delta brush

Criteria & assessment

subtypes

+F

Superimposed theta-or-faster activity, rhythmic or not, on PDs or RDA. It must be part of the pattern, not merely background; for PDs it may be continuous if absent when PDs are absent, or occur regularly with each discharge.

+R

Superimposed rhythmic or quasi-rhythmic delta activity; PDs only.

+S

Associated sharp waves, spikes, or sharp contour; RDA only; present at least once per 10 s and not an SW pattern.

combinations

• PDs+FR
• RDA+FS

bilateral rule

If a bilateral pattern qualifies for plus on only one side, the overall main term still receives the plus modifier.

EDB

definite

Abundant or continuous RDA+F with fast activity stereotypically related to the delta wave, or abundant/continuous PDs+F where each PD is a single blunt delta wave and fast activity is stereotypically related to that delta wave.

possible

Meets either EDB form but is only occasional/frequent, or the fast activity lacks a stereotyped delta-wave relationship.

not EDB

RDA+F/PDs+F lacking both required EDB conditions; a periodic pattern can be EDB only if PDs are blunt delta brushes; fast activity between delta waves or present as background does not qualify.