New Seizure Classifications Revealed at American Epilepsy Society Conference

DECEMBER 03, 2016
Laurie Toich, Assistant Editor
For the first time, the new International League Against Epilepsy (ILAE) seizure classifications were presented at the American Epilepsy Society conference during the Annual Fundamentals Symposium: The New Definition and Classification of Epilepsy on Friday, December 2, 2016.

The 2017 ILAE Seizure Classifications were created by numerous individuals over the past 12 years, according to the presenter Robert Fisher, MD, PhD, who was also a part of the Seizure Classification and Revision Task Forces for the guidelines.

The classifications were approved by the ILAE just 1 week prior to the presentation. Attendees of the session were the first to see these classifications, highlighting the advantage of attending conferences.
The previous international classifications had been in effect since 1981, but since then, there has been much advancement in the areas of epilepsy treatment and research.

According to the session, there were multiple reasons to revise the classifications. The 1981 classifications made it difficult to classify certain seizures. Furthermore, they did not use consciousness as an aspect of seizures, even though it can help physicians to diagnose epilepsy. In addition, certain important seizure types were not included in the previous classifications, and certain terms were used that are not fully accepted or understood by the public.

For the new classifications, the authors created an operational system because not enough is known about the underlying pathophysiology of the seizure types to create a more scientific system, Dr Fisher said.

Under the new guidelines, some seizures may be classified as having a focal or generalized onset, and seizures due to unknown causes may be classified.

The new guidelines also provide health care professionals with an updated meaning of unconsciousness, which has been changed to the term impaired awareness. Classifying a seizure based on awareness can be important for practical considerations, such as driving, safety during seizures, employability, and learning, according to the session.

Generally, the public views “unconscious” as an unresponsive patient lying on the ground, which may not be true for all patients who experience impaired awareness during a seizure, Dr Fisher said. By having a better grasp of the meaning of consciousness, patients will better understand the risks they may face.

Additionally, a better understanding of impaired awareness will allow physicians and other health care professionals to recognize that an affected patient may be awake.

To help with public clarity, the 2017 classifications changed the term partial seizures to focal seizures, as well as generalized tonic-clonic to focal to bilateral tonic-clonic, according to the session.

Supportive information, such as videos, electroencephalogram patterns, lesions that are discovered through neuroimaging, gene mutations, and a previous epilepsy diagnosis, helps provide a more accurate diagnosis. In the previous classifications, these elements were not highly used for diagnosis.

These revised classifications are expected to help health care professionals diagnose epilepsy. Affected patients should also have a better understanding of their disease, which could lead to beneficial outcomes.
 

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