Introduction and nosologies

Abnormal motor movements are frequently seen in newborn infants and may present diagnostic dilemmas. This chapter will describe most of the motor events occurring in this epoch and will offer parameters useful in distinguishing those that are seizures from those that are not. This is not always an easy task. It is, however, not only of considerable theoretical interest but also of clinical importance to better guide therapies and delineate prognosis. Over the past few decades, there has been an unfortunate trend in neonatology to consider non-epileptic movement disorders as seizure events. Hence, newborns often receive unwarranted anticonvulsant drugs, which is a trend that has replaced the previous one of underdiagnosing neonatal seizures.

This quandary of overdiagnosing and overtreating is compounded by nosological problems peculiar to the age. The first is whether all neonatal seizures should be classified as epileptic events or not. For example, should one diagnose a neonatal seizure after a transient metabolic insult, such as hypocalcemia, hypoglycemia, or withdrawal states because of maternal drug abuse? This issue has been debated extensively, and the interested reader can refer to a few pertinent articles containing different views (Wasterlain & Vert, 1990; Wasterlain & Sharasaka, 1994; Hrachovy et al., 1990; Lombroso, 1993, 1996; Scher & Painter, 1989; Shewman, 1990; Volpe, 1995).

A second source for diagnostic confusion is that, in some neonates, there may be, in addition to seizures, some abnormal movements that are not seizures, while these may exhibit quite a diverse phenotypic expression in the same baby.