Electroencephalography in neonatal epilepsies

Abstract

Neonatal epilepsiesneonatal seizures caused by remote symptomatic etiologiesare infrequent compared with those caused by acute symptomatic etiologies. The etiologies of neonatal epilepsies are classified into structural, genetic, and metabolic. Electroencephalography (EEG) and amplitude-integrated EEG (aEEG) are essential for the diagnosis and monitoring of neonatal epilepsies. Electroencephalography / aEEG findings may differ substantially among infants, even within infants with variants in a single gene. Unusual EEG/aEEG findings, such as downward seizure patterns on aEEG, can be found. Neonatal seizures are exclusively of focal onset. An International League Against Epilepsy task force proposed that the seizure type is typically determined by the predominant clinical feature and is classified into motor or non-motor presentations. Ictal EEG usually demonstrates a sudden, repetitive, evolving, and stereotyped activities with a minimum duration of 10 s. In epileptic spasms and myoclonic seizures, the cutoff point of 10 s cannot be applied. One must always be aware of electro-clinical dissociation in neonates suspected to have seizures. Amplitude-integrated EEG is also useful for the diagnosis and monitoring of neonatal epilepsies but aEEG cannot be recommended as the mainstay because of its relatively low sensitivity and specificity. At present, EEG findings are not pathognomonic, although some characteristic ictal or interictal EEG findings have been reported in several neonatal epilepsies. Deep learning will be expected to be introduced into EEG interpretation in near future. Objective EEG classification derived from deep learning may help to clarify EEG characteristics in some specific cases of neonatal epilepsy.

Neonatal Seizures: An Overview of Genetic Causes and Treatment Options

“…Neonatal seizures etiopathogenesis can be ascribed to an acute event (such as hypoxicischemic encephalopathy, intracranial haemorrhage, stroke, infection or electrolyte disturbances) or symptomatic conditions (namely genetic, metabolic or structural ones), outlining the so-called 'Neonatal Epilepsies' [1,8].…”

“…Metabolic disorders, as well as malformations (structural conditions), have in fact a genetic cause, even though detecting the causative pathogenic variant is not always easy. Uncoupling the aetiologies may be therefore difficult and even improper [8]. In this regard, the latest International League Against Epilepsy (ILAE) Task Force on Neonatal Seizures [9] proposed a reorganised, less rigid and nonhierarchical diagnostic classification.…”

“…It is possible to taxonomize epilepsies in more than one category (genetic, metabolic, structural, immune and unknown) which are no longer considered mutually exclusive. Since genetic, metabolic and structural causes explain the 10-15% of all neonatal seizures, this approach is useful in providing an appropriate diagnostic assessment, allowing an adequate and early treatment initiation and preventing poor outcomes [1,2,4,7,8,10].…”

“…Nowadays, these conditions are mostly considered genetic disorders, even when a metabolic or structural cause is revealed, strongly supporting the importance of the application of the ILAE classification. Monogenic mutations could result in a loss of function (Lof) or a gain of function (Gof) of the gene product, which may be detected in most of these cases [2,8]. Different pathogenic variants within the same gene may result in opposite effects (LoF or GoF) on the gene product, hence on the clinical phenotype, requiring diverse treatment options [11].…”

Neonatal seizures: How should we make a diagnosis and management?

“…2 In this issue of the Journal, Akihisa Okumura, one of the excellent experts in neonatal neurology in Japan, reviews neonatal epilepsies, placing emphasis on the importance of EEG for their diagnosis and management. 4 This review paper is published as a critical part of proceedings of the 20th Annual Meetings of Infantile Seizure Society (http://www.issjpn.info/) held in Nagoya, 2019, illustrating updated topics in the field of neonatal epilepsies as well as neonatal seizures. Most neonatal seizures occur in association with acute brain insults as described above, a part of them can be initial provocation of epilepsy in the neonatal period.…”