Understanding & management of interictal-ictal continuum (IIC)

The IIC is synonymous with “possible electrographic seizure” or “possible electrographic status epilepticus.”The IIC is a purely electrographic term that is NOT a diagnosis; it requires careful interpretation in the full clinical context. The pattern on the IIC, does not qualify as an electrographic seizure or SE, but there is a reasonable chance that it may be contributing to impaired alertness, causing other clinical symptoms, and/or contributing to neuronal injury. Thus, it is potentially ictal in at least some sense and often warrants a diagnostic treatment trial, typically with a parenteral antiseizure medication.IIC is defined as any periodic discharge (PD) or spike-and-wave (SW) pattern, with frequency between ۱.۰ to ۲.۵ Hz lasting ≥ ۱۰ seconds OR any PD or SW pattern that averages ≥۰.۵ Hz and ≤۱.۰ Hz over ۱۰ seconds plus modifier or fluctuation or any lateralized rhythmic activity more than ۱ Hz for ≥ ۱۰ seconds with a plus modifier or fluctuation. This includes any Lateralized rhythmic delta activity (RDA), bilateral independent RDA, unilateral independent RDA, and multifocal independent RDA, but not generalized RDA.Moreover, in this presentation, difference kinds of lateralized periodic discharges (LPDs) including interictal/irritative brain injury versus ictal/peri-ictal LPDs will be discussed.