Minor modifiers

Criteria & assessment

onset

sudden

Absent to well-developed within 3 s.

gradual

Does not meet sudden-onset definition.

triphasic morphology

Three negative-positive-negative phases, each longer than the preceding and the positive phase of highest voltage; or positive-negative biphasic appearance when a low-voltage first negative phase is obscured by background. PDs and SW only.

anterior posterior lag

Consistent measurable delay >100 ms from most anterior to most posterior derivation, or reverse; report typical anterior-to-posterior delay in ms (negative for posterior-to-anterior) in longitudinal bipolar and referential montage, preferably ipsilateral-ear reference. PDs or spike/sharp component of SW only.

polarity

values

• positive
• negative
• dipole, tangential
• unclear

rule

Describe dominant/highest-voltage phase in a referential montage; PDs or spike/sharp component of SW only.