Doose Syndrome (EMAtS)

By Dovy Paukstys, Founder, Komori Care

This article is educational and is not medical advice. It does not diagnose, treat, prevent, or cure any condition. Komori is not a medical device, is not FDA-cleared, does not detect seizures, and is not intended for people with epilepsy. Talk with a neurologist or epileptologist about personal medical decisions. Households living with epilepsy should use clinically validated seizure-detection devices as directed by their care team.

Parents still say Doose. Charts now say EMAtS. Same syndrome. Different decade of naming.

I'm not a neurologist. I don't have epilepsy. I read the ILAE pages and the Doose Syndrome Epilepsy Alliance so this hub uses both names and does not mix this up with LGS. People do that. They shouldn't.

The official name

ILAE: epilepsy with myoclonic-atonic seizures. Previously Doose syndrome. Previously myoclonic-astatic epilepsy.

Abrupt onset of multiple generalized seizure types in early childhood, including the myoclonic-atonic drop. Development often stalls or slides while the seizures are hot. Seizures can look drug-resistant at first. Two thirds of children still reach epilepsy remission, usually within 3 years of onset.

That's the sentence that makes this different from LGS. Remission is on the table. Not promised. On the table.

ILAE tags EMAtS as an epileptic encephalopathy. The active seizures can knock development off course. When they settle, some of that can move again.

Who it hits, and when

ILAE: usually 2 to 6 years. Full range 6 months to 8 years. Both sexes, more boys. Birth history usually boring. Neuro exam and head size normal. About a quarter had febrile seizures first.

Prior development and cognition are typical in two thirds. The Alliance says kids are usually developing normally before onset, median around age 3, window 1 to 5.

Onset under 6 months or over 8 years is exclusionary. Moderate or greater impairment before the first seizure is an alert. Abnormal exam is an alert. A structural cause on MRI is exclusionary. If the MRI explains the epilepsy, ILAE does not want this label.

About 5 percent of cases are glucose transporter 1 deficiency. ILAE puts a caution on that because it changes treatment. I'm not walking through the diet here. I'm saying: this is one of the reasons a clinician hunts a cause even when the story "sounds like Doose."

The drop is the hallmark

Mandatory seizure: myoclonic-atonic. A jerk, then the tone goes. The Alliance describes it as someone cutting the strings on a marionette. Torso slumps. Legs give. Face can hit the floor. If it happens standing, injuries are not theoretical.

The Alliance says every child with this syndrome has myoclonic seizures or myoclonic-atonic seizures or both. Other generalized types pile on. Tonic-clonic. Absence. Myoclonic without the drop. Nonconvulsive status. Tonic seizures are less common and ILAE treats early tonic seizures as a warning.

Tonic seizures within 12 months of onset are an alert. They make people think LGS. Epileptic spasms and focal seizures are exclusionary. Those belong to other syndromes.

Nonconvulsive status can look like a long stretch of being "off." The Alliance says it can last a half hour, an hour, or days. Still a medical problem. Different from convulsive status, which CDC and NINDS treat as an emergency at five minutes.

EEG

Mandatory: generalized 2 to 6 Hz spike- or polyspike-wave.

Background starts normal. Biparietal theta can show up. When seizures get frequent, generalized slowing can too.

Alerts that push you toward a different diagnosis: generalized paroxysmal fast activity in sleep, slow spike-wave under 2.5 Hz, photoparoxysmal response at low flash frequencies (think CLN2). Persistent focal abnormality or hypsarrhythmia are exclusionary.

The myoclonic piece of the drop lines up with a generalized spike or polyspike. The atonic piece lines up with the slow wave after.

MRI is done to exclude other causes, not to prove EMAtS. Ictal EEG is not required unless LGS or infantile spasms are in the differential. Then ILAE wants video or ictal confirmation of the drop.

In a clinic with no EEG, they allow the diagnosis if a clinician has seen the myoclonic-atonic seizures. They still want the EEG.

How it differs from LGS

This is the mix-up.

LGS: tonic seizures required, slow spike-wave, sleep paroxysmal fast activity, almost no remission, most kids already delayed or become so.

EMAtS: myoclonic-atonic required, 2 to 6 Hz spike-wave, structurally normal MRI, many kids typical before onset, two thirds remit.

ILAE built those tables so people would stop using the names as synonyms. I'm with the table.

Early tonic seizures, recurring nonconvulsive status, slow spike-wave, or sleep fast activity are the ILAE flags for a worse EMAtS course, and for "are we sure this isn't LGS."

Course

Two thirds remit, usually inside 3 years. The remaining third keep seizures and developmental problems.

During the storm: behavior issues, sleep issues, executive dysfunction, ataxia. ILAE lists those with the active phase.

The Alliance is honest that outcomes vary. Some kids become seizure-free on treatment or on their own. Some keep seizures into adolescence and after. Maximize the kid in front of you. That's their line. Fine by me.

Treatment, no doses

I'm not listing a first-line cocktail. I'm not dosing valproate or anything else.

NINDS's general page covers the toolbox for hard epilepsies. Medicines. Ketogenic diet under a team. Sometimes devices or surgery when the picture is different from classic EMAtS. GLUT1, if found, is its own plan.

The Alliance points families to epileptologists at epilepsy centers. Correct.

Households living with epilepsy should use clinically validated seizure-detection devices as directed by their care team. A consumer monitor does not diagnose Doose and does not catch every drop.

Helmets and furniture corners are safety, not treatment. First aid is still CDC: stay, safe, side, 911 if it goes past five minutes or repeats.

FAQ

Is Doose syndrome the same as EMAtS?

Yes. ILAE's current name is epilepsy with myoclonic-atonic seizures. Doose syndrome and myoclonic-astatic epilepsy are the older names. Same electroclinical syndrome.

What is a myoclonic-atonic seizure?

A brief jerk followed by a loss of tone. That's the drop. ILAE requires this type for the diagnosis. The Alliance calls it the hallmark that separates this from nearby syndromes.

Do most children outgrow it?

ILAE says two thirds reach epilepsy remission, usually within 3 years of onset. The other third do not. Remission is common. It is not everyone.

How is this different from LGS?

Different required seizure, different EEG, different MRI story, different outlook. Tonic plus slow spike-wave plus sleep fast activity is LGS. Myoclonic-atonic plus 2 to 6 Hz spike-wave plus a normal MRI is EMAtS. A neurologist has to draw that line.

Sources

• ILAE / epilepsydiagnosis.org, EMAtS overview: https://www.epilepsydiagnosis.org/syndrome/epilepsy-myoclonic-atonic-overview.html
• ILAE / epilepsydiagnosis.org, EMAtS diagnostic criteria: https://www.epilepsydiagnosis.org/syndrome/epilepsy-myoclonic-atonic-diagcriteria.html
• ILAE / epilepsydiagnosis.org, EMAtS EEG: https://www.epilepsydiagnosis.org/syndrome/epilepsy-myoclonic-atonic-eeg.html
• Doose Syndrome Epilepsy Alliance, What is Doose syndrome?: https://doosesyndrome.org/parents-and-caregivers/what-is-doose-syndrome/
• Doose Syndrome Epilepsy Alliance, How is it Diagnosed?: https://doosesyndrome.org/parents-and-caregivers/how-is-it-diagnosed/
• Doose Syndrome Epilepsy Alliance, What Are The Seizure Types: https://doosesyndrome.org/parents-and-caregivers/what-are-the-seizure-types/
• ILAE / epilepsydiagnosis.org, Encephalopathy: https://www.epilepsydiagnosis.org/encephalopathy.html
• NINDS, Epilepsy and Seizures: https://www.ninds.nih.gov/health-information/disorders/epilepsy-and-seizures
• CDC, First Aid for Seizures: https://www.cdc.gov/epilepsy/first-aid-for-seizures/index.html