ictal

Ictal is a medical term used to describe the period during which a seizure is actively occurring. Derived from the Latin ictus, meaning "stroke" or "attack," ictal denotes the time from seizure onset to termination of clinical and electrographic seizure activity. The ictal phase is contrasted with the interictal period, the interval between seizures, and the postictal phase, the recovery period that follows a seizure.

Clinically, ictal phenomena vary with seizure type and focal origin. They can include rhythmic muscle contractions, loss of awareness, automatisms, sensory or autonomic changes, or generalized convulsions. Nonconvulsive ictal events may present as altered consciousness without prominent motor activity. Electroencephalography (EEG) during the ictal phase shows evolving, sustained rhythmic discharges that correspond to the seizure onset zone and may spread to other regions. Imaging such as MRI may identify structural pathology related to seizure onset, but ictal imaging is less common than interictal imaging.

In epilepsy management, distinguishing ictal from interictal and postictal periods aids diagnosis and treatment planning. Identification of ictal onset zones supports localization-related epilepsy workups and can inform surgical candidacy. Acute termination of ictal activity is a primary goal of emergency treatment with antiseizure medications.