Seizures in neonates (newborns) remain the most frequent neurological problem in the nursery. Considerable debate about their consequences exists between data and deductions reached through animal experimentations and those obtained through clinical investigations. The main conflicting issues are whether seizures in newborns can plant the roots for epileptogenesis and cause long-term deficits.
Most neonatal seizures occur over a short time, usually only for a few days. Fewer than half of the affected infants develop seizures in later life. Such neonatal seizures are considered acute reactive (acute symptomatic), and thus the term neonatal epilepsy is not used to describe these seizures. The incidence of neonatal seizures has not been clearly established, although an estimated frequency of 80-120 cases per 100,000 neonates per year has been suggested. The incidence of seizures is higher in the neonatal period (i.e., the first 4 wk after birth) than at any other time of life
Classification
Clonic seizures
These movements most commonly are associated with electrographic seizures. They often involve 1 extremity or 1 side of the body. The rhythm of the clonic movements is usually slow, at 1-3 movements per second.
Tonic seizures
These may involve 1 extremity or the whole body. Focal tonic seizures involving 1 extremity often are associated with electrographic seizures.
Generalized tonic seizures often manifest with tonic extension of the upper and lower limbs and also may involve the axial musculature in an opisthotonic fashion. Generalized tonic seizures mimic decorticate posturing; the majority are not associated with electrographic seizures.
Myoclonic seizures
These may occur focally in 1 extremity or in several body parts (in which case they are described as multifocal myoclonic seizures).
Focal and multifocal myoclonic seizures typically are not associated with electrographic correlates. Generalized myoclonic jerks are possibly the clinical equivalent of infantile spasms.