How can we identify ictal and interictal abnormal activity?

Area of Science:

• Neuroscience
• Epilepsy Research
• Clinical Neurology

Background:

• The International League Against Epilepsy (ILAE) definition of a seizure, established historically, does not fully encompass current epilepsy and neuroscience advancements.
• Clinical seizure diagnosis is empirical, relying on symptom patterns and excluding seizure mimics.
• The temporal boundaries of seizure states (ictal, interictal, postictal) are often unclear.

Purpose of the Study:

• To critically evaluate the current definition of a seizure in light of recent research.
• To highlight challenges in distinguishing seizures from normal behavior in basic science research.
• To emphasize the importance of defining seizure onset, duration, and network involvement for clinical and preclinical studies.

Main Methods:

• Discussion of clinical diagnostic challenges, including seizure mimics and temporal delimitation.
• Exploration of electroencephalogram (EEG) patterns during seizures and their diagnostic utility.
• Examination of basic science challenges in quantifying seizures in animal models, including differentiating seizure activity from normal behavior.

Main Results:

• Current seizure definitions may not adequately capture the complexity of neuronal activity.
• EEG is valuable for seizure confirmation, classification, and localization, with several common patterns observed.
• Accurate quantification of seizures in preclinical studies requires precise definition of seizure onset and cessation.

Conclusions:

• There is a need to refine the definition of a seizure to align with contemporary epilepsy and neuroscience research.
• Understanding seizure initiation, propagation, and network involvement is crucial for developing effective interventions.
• Further research is essential to clarify the pre-ictal, ictal, and post-ictal states and their potential causal links.