EPILEPSY WITH MYOCLONIC ATONIC SEIZURES (EMAtS)

	Mandatory	Alerts	Exclusionary
Seizures	Myoclonic-atonic seizures	Tonic seizures within 12 months of epilepsy onset	Epileptic spasms Focal seizures
EEG	Generalized 2-6Hz spike- or polyspike-wave	Generalized paroxysmal fast activity in sleep Generalized slow (<2.5Hz) spike-wave Photoparoxysmal response at low flash frequencies (suggests CLN2)	Persistent focal abnormality Hypsarrhythmia
Age at onset			<6 months or >8 years
Development at onset		Moderate or greater impairment prior to seizure onset
Neurological exam		Abnormal exam
Imaging			Structural cause for the epilepsy
Are MRI or ictal EEG required for diagnosis? An MRI is not required for diagnosis but is done to exclude other causes An ictal EEG is not required, however in a child with alerts or features suggestive of Lennox-Gastaut syndrome or infantile epileptic spasms syndrome, ictal EEG or video confirmation of myoclonic-atonic seizures is recommended.
Syndrome in evolution: this syndrome should be suspected when there is explosive onset of multiple generalised seizure types in an appropriately aged child without alerts or exclusionary features
Syndrome without laboratory confirmation: in resource-limited regions, this syndrome can be diagnosed without EEG if the clinician has witnessed myoclonic-atonic seizures (directly or on video). However EEG is strongly recommended to support the diagnosis.

NOTE Alert criteria are absent in the vast majority of patients with the syndrome, but rarely can be seen. Their presence should result in caution in diagnosing the syndrome and consideration of other conditions