EPILEPTIC STEREOTYPIES

Stereotypies are defined as repetitive, similar, non-goal-directed (purposeless) movements. Purposeless repetitive motor behaviors are typical manifestations of seizures of temporal or frontal origin and are referred to as automatisms, or “epileptic automatisms” or sometime as “epileptic stereotypies” (Penfield,1959). In adults, they are usually recognized as clearly different from the normal patient's behavior, and also because there are other associated epileptic manifestations. When stereotypies are the only epileptic symptoms, and specially in young and developmentally abnormal children with mental retardation and particularly those within the autistic, spectrum, the diagnosis is more difficult because various types of non-epileptic stereotypies are common in these children in whom epilepsy is also quite frequent. In these children, subtle associated changes in awareness, vigilance or in cognitive capacity, suggestive of epilepsy may be difficult to recognize. It is exceptionally possible to show with simultaneous EEG recording that the repetitive abnormal movements are ictal or postictal manifestations. They probably represent the release of lower motor programs secondary to the epileptic activity. Sometime, they represent one among other signs of neurological dysfunction in children with so-called epileptic encephalopathies and can disappear when the epileptic disease is in remission, but the relationship with the epileptic activity per se is uncertain.. The diagnostic problems in differentiating between common stereotypies, complex tics, other dyskinesias and epileptic stereotypies will be discussed. In the latter instance, the movements can appear goal-directed and interpreted as such, even when they are not made with a deliberate intention (for instance, chasing an insect on one's face or looking at one's hand). They are not always similar with variations in intensity, rapidity and complexity from one episode of stereotypy to the next with no precise rythmicity. The circumstances of occurrence, the associated neurological signs or symptoms and the underlying pathological conditions are equally important diagnostic indices.