Perioral myoclonia with absences misdiagnosed as focal motor seizures (EEG)

From video EEG of an 18-year-old woman with perioral myoclonia (mainly repetitive jaw jerks) with absences. She was referred because of “focal motor seizures and secondarily GTCS.” She had onset of GTCSs and absences at age 11 years. Seizures continued despite treatment with appropriate AED combinations, such as valproate, ethosuximide, clonazepam, lamotrigine, and acetazolamide. Absences were frequent, often in daily clusters, and consisted of brief (about five seconds), moderate impairment of consciousness and violent rhythmic jerking of the jaw. GTCSs occurred between one and 10 times per year, usually after awakening and were preceded by clusters of absences, with the jaw myoclonus spreading to limb jerks prior to generalized convulsions. She was more concerned about the absences because they interfered with her daily life “everyone notices the jerks of my jaw” and less with the GTCS, which usually occurred at home. The initial misdiagnosis of “focal motor seizures” was because the jaw-jerking was described by her mother as unilateral. (Used with permission from: Panayiotopoulos CP. A Clinical Guide to Epileptic Syndromes and Their Treatment. Revised 2nd ed. London: Springer, 2010.)