Epilepsy with myoclonic-atonic seizures (EMAtS) is a childhood developmental and/or epileptic encephalopathy characterised by myoclonic-atonic seizures and generalised epileptiform EEG abnormalities. It was previously widely known as Doose syndrome.
The syndrome usually begins in early childhood, often after a period of normal development. During the active phase, seizures can become frequent and development may stagnate or regress.
The defining seizure
A myoclonic-atonic seizure begins with a brief myoclonic jerk, often involving the shoulders or proximal muscles, followed immediately by a brief loss of muscle tone.
The atonic component may cause only a head nod or knee buckle, or it may produce a sudden fall.
Why the distinction from a pure atonic seizure matters
A pure atonic seizure causes sudden loss of tone without the initial myoclonic jerk.
Both can occur in EMAtS, but the presence of true myoclonic-atonic seizures is mandatory for the syndrome diagnosis.
Typical age at onset
The syndrome usually begins between 2 and 6 years of age. The ILAE excludes classic EMAtS when onset is below 6 months or above 8 years.
Boys are affected more often than girls in reported cohorts.
Development before seizure onset
Development is normal before seizures begin in about two thirds of affected children.
Moderate to severe developmental delay already present before seizure onset is an alert feature and should prompt consideration of another developmental epilepsy.
Other seizure types
Children may also have generalised tonic-clonic seizures, absence seizures, atonic seizures, myoclonic seizures and episodes of non-convulsive status epilepticus.
Focal seizures are exclusionary in the ILAE criteria for classic EMAtS.
The EEG pattern
The mandatory EEG feature is generalised 2–6 Hz spike-wave or polyspike-and-wave activity.
Myoclonic-atonic seizures show a generalised spike or polyspike associated with the jerk followed by a slow wave corresponding to the loss of tone.
Why EEG plus muscle recording can help
Simultaneous EMG during video-EEG can demonstrate the brief muscle activation of the myoclonic component followed by loss of muscle activity during the atonic phase.
This can be useful when the visible seizure is simply described as a sudden fall.
What argues against EMAtS?
Epileptic spasms, a previous infantile epileptic spasms syndrome, focal seizures, hypsarrhythmia or a causative focal brain lesion argue against classic EMAtS.
Tonic seizures very early in the course are an alert because they can suggest Lennox–Gastaut syndrome.
MRI
MRI is not required for diagnosis but is usually performed to exclude a structural cause.
A clear causal structural lesion would make another epilepsy classification more appropriate.
Genetics
EMAtS has heterogeneous genetic causes. No single gene explains most cases.
Genetic testing can identify a cause in a subset, particularly when there is developmental impairment, a strong family history or unusual neurological features.
Development during the active phase
Children can show developmental stagnation or regression during periods of frequent seizures and heavy epileptiform activity.
When seizures and EEG improve, developmental progress may resume. Some children return close to their previous level, while others are left with lasting intellectual or behavioural difficulties.
Non-convulsive status epilepticus
Some children develop prolonged periods of reduced responsiveness with frequent generalised spike-wave activity.
Recurrent non-convulsive status is associated with a less favourable developmental outcome.
Treatment evidence
There is no single universally proven first-line medicine for EMAtS. Broad-spectrum antiseizure medicines are generally used, and treatment often requires combinations.
Valproate, clobazam, ethosuximide, lamotrigine and other broad-spectrum medicines are used in clinical practice depending on the seizure mixture and individual circumstances.
Ketogenic dietary therapy
Ketogenic dietary therapy is an important treatment option for drug-resistant EMAtS and is commonly considered earlier than in many other epilepsies because some children respond substantially.
It requires specialist dietetic and medical supervision.
Why sodium-channel blockers need caution
Medicines used mainly for focal epilepsy can aggravate some generalised seizure types.
Treatment should therefore be guided by syndrome classification and the full seizure mixture rather than by one isolated convulsive event.
Injury risk
Myoclonic-atonic and atonic seizures can cause abrupt falls, facial injuries and head trauma.
Safety planning may include environmental adaptation or protective headgear in selected children, although these measures cannot remove all risk.
Prognosis
The long-term course is variable. Some children enter remission and regain developmental momentum, while others continue to have seizures, intellectual disability, aggression or hyperactivity.
Poorer outcomes have been associated with tonic seizures, recurrent non-convulsive status and highly active slow or fast generalised EEG abnormalities.
Worldwide diagnosis
The ILAE allows a presumptive diagnosis in resource-limited settings when a clinician has directly witnessed a convincing myoclonic-atonic seizure or reviewed a clear family video and no exclusionary features are present.
EEG is still strongly recommended because several other childhood epilepsies can cause sudden falls.
The central point
EMAtS is not simply “drop attacks”. The defining seizure contains both a myoclonic jerk and an atonic loss of tone, and the syndrome has a characteristic early-childhood course with generalised EEG abnormalities.
Related reading
Epilepsy Syndromes →
Lennox–Gastaut Syndrome →
Ketogenic Dietary Therapy →
Epilepsy in Children and Young People →
Sources
- ILAE — Classification and definition of epilepsy syndromes with onset in childhood
- ILAE childhood epilepsy syndrome position paper
Medical note: sudden falls in a child can have several epileptic and non-epileptic causes. Video-EEG can be especially helpful when seizure type is uncertain.
Evidence checked: September 2026.