Neonatal Seizures

Neonatal seizures are classified as clonic, tonic, and myoclonic. Clonic seizures consist of rhythmic jerking of groups of muscles and occur in either a focal or multifocal pattern. In multifocal clonic seizures, movements may migrate from one part of the body to another. Although focal seizures may be seen with localized brain insults, such as neonatal strokes, they may also be seen in disorders that diffusely affect the brain, such as asphyxia, subarachnoid hemorrhage, hypoglycemia, and infection. In tonic seizures, the infant develops asymmetric posturing of the trunk or deviation of the eyes to one side. Myoclonic seizures are similar to those seen in older children, consisting of rapid jerks of muscles. The myoclonic seizures can consist of bilateral jerks, although occasionally unilateral or focal myoclonus can occur.

Sick neonates often display repetitive, stereotyped behavior that may be confused with seizures. These behaviors include repetitive sucking and other oralbuccal-lingual movements, assumption of an abnormal posture, pedaling movements of the legs or paddling movements of the arms, blinking, momentary fixation of gaze with or without eye deviation, nystagmus, and apnea. However, when these behaviors are observed during EEG recordings, epileptiform activity is usually not recorded. Likewise, when tonic posturing involves all four extremities and the trunk, an associated EEGepileptiform discharge rarely appears. Myoclonus not associated with epileptiform discharges can also be seen in sick neonates.

Whereas the diagnosis of seizures relies primarily on clinical observation, the EEG may be extremely valuable in confirming the presence of epileptic seizures. In addition, the EEG is very useful in the detection of electrographic seizures in paralyzed infants or in assessing response to antiepileptic medications.

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