Arc de cercle as a manifestation of focal epileptic seizures

Since its description in 1885 in the Etudes cliniques sur l'hystero-epilepsie ou grand hysterie by Raul Richer, the arc de cercle , or circular arc (figure 1A), has become synonymous of psychogenic nonepileptic seizures (PNES) and automatically interpreted as such by physicians. The development of extracranial and intracranial EEG recording has not confirmed the clinical importance of the arc de cercle .