International League Against Epilepsy task force issues framework for neonatal seizures

A neonatal seizures task force established by the International League Against Epilepsy, or ILAE, published a new classification and framework for neonatal seizures that aligns with the ILAE’s 2017 classification of seizures and epilepsies.

“The 2017 ILAE Position Papers on Classification of Seizure Types and the Epilepsies presented a framework for classification including seizure types, epilepsy types and syndromes,” the researchers wrote. “The ILAE Commission on Classification & Terminology recognized that seizures in the neonate require special considerations and therefore a Neonatal Task Force was established with the aim of integrating seizures and epilepsies in this age group into the 2017 ILAE Classification.”

Historically, attempts to classify and describe neonatal seizures aimed at emphasizing the differences between these and seizures in older children and adults, according to Ronit M. Pressler, MD, PhD, MRCPCH, CCT, a consultant in clinical neurophysiology and clinical lead of the EEG-video telemetry unit at Great Ormond Street Hospital for Children and professor of clinical neuroscience at UCL Institute of Child Health, both in London, and colleagues. In the present report, the researchers aimed to “use terminology consistent with the 2017 ILAE Classification of Seizures and the Epilepsies.”

The task force worked to categorize seizures in neonates in a way that:

• could be incorporated into the 2017 ILAE classifications;
• was based on electroclinical phenotype;
• underlined the “key role” of EEG in diagnosing neonatal seizures;
• had implications for managing and treating events;
• was acceptable to neonatologists, pediatricians, epileptologists, neurophysiologists and neurologists; and
• had application in all health care settings.

The resulting classification framework “emphasizes the role of EEG in the diagnosis of seizures in the neonate and includes a classification of seizure types relevant to this age group,” according to Pressler and colleagues. It reviews presentation, diagnosis/differential diagnosis, seizure types and epilepsy syndromes.

Regarding presentation, the framework stated that “newborns may present with paroxysmal clinical events suspected to be seizures of epileptic origin,” including motor and non-motor phenomena. The researchers noted, however, that many neonates experience “mostly or exclusively electrographic-only seizures” that are only traceable on EEG or amplitude-integrated EEG.

As a result, in discussing diagnosis/differential diagnosis, Pressler and colleagues wrote that video EEG recording “is the gold standard for diagnosis” in neonates while also acknowledging that not all neonatal units have access to EEG equipment. In those instances, the task force supported the use of amplitude-integrated EEG, “a simplified bedside neurophysiology tool displaying one or more commonly two channels of EEG in a filtered and compressed manner,” though the limitations of that tool — which is used with co-registration of raw channels — “are well recognized.”

In neonates, seizure type is determined by the predominant clinical feature, according to the framework. In addition, “as many neonatal seizures are electrographic-only with no evident clinical features,” the task force did not include these in the classification, nor did they include clinical events with no EEG correlate. Finally, they stated that the grouping of focal vs. generalized seizures was not warranted, as seizures during the neonatal period “have been shown to have a focal onset.”

According to the researchers, seizures during this period “can have a motor (automatisms, clonic, epileptic spasms, myoclonic, tonic), non-motor (autonomic, behavior arrest) or sequential presentation,” and the classification developed by the task force “allows the user to choose the level of detail when classifying seizures in this age group.”

Regarding epilepsy syndromes, Pressler and colleagues noted that most seizures in the neonatal period are the result of an acute illness, though some seizures may be the first indication of early infantile epilepsy. As a result, “early differentiation” of provoked seizures from neonatal-onset epilepsies is important, because the evaluation and long-term treatment of neonatal epilepsies are unique, according to Pressler and colleagues.

“Recent advances in neuroimaging and genomic technology as well as the implementation of video-EEG in the [neonatal ICU] allow for the identification of more discrete, etiology-specific neonatal epilepsy syndromes than previously recognized,” the researchers wrote. “It is likely that the combination of more sophisticated genetic testing and video-EEG monitoring will allow the identification and stratification of distinct etiology-specific electroclinical phenotypes, as suggested in the new ILAE classification of the epilepsies. This framework has been adapted for neonates.”