Cortical myoclonic tremor induced by fixation-off sensitivity An unusual cause of insomnia

Fixation-off sensitivity (FOS) refers to seizures or EEG abnormalities elicited by the elimination of central vision/fixation, even in the presence of light.1 Typically, a paroxysmal discharge occurs within 1–3 seconds of eye closure, persists throughout the eye-closed state, and disappears immediately on eye opening.2