Individuals with MECP2 duplication syndrome have a wide variety of seizures (e.g., myoclonic, atonic, hypermotor, generalized tonic-clonic). Some also have episodes where muscle tone is lost for prolonged periods (often 10 -30 minutes) with clouded consciousness. Often, the loss of muscle tone only affects the neck so the head hangs limp, but sometimes the whole body seems to be limp as in flaccid paralysis. Have seizures like this been seen in others and have they been investigated? Are these Focal Atonic Seizures?
According to the 2017 ILAE seizure classification paper, atonic seizures could fall under the category of "Seizures with focal onset" either aware or with impaired awareness.
In fact, loss of axial muscle tone is probably the most common presentation of an atonic seizure. Segmental loss of neck muscle tone is commonly seen in atonic seizures of small children.
On the other hand, seizures with loss of muscle tone with a duration of > 30 min are unusual. Maybe what you are seeing is a postictal phenomenon (Todd's paralysis)??
Robert Fisher's paper about seizure classification.Article Operational classification of seizure types by the Internati...
Atonic seizure is a semiological description, that does not imply a definite underlying pathophysiology.
In the case of MECP2 duplication syndrome, it may be that a cluster of seizures occurred.
See https://mecp2.wordpress.com/category/seizures/
I agree with Dr. Ulbricht when he says that what you may be seeing is a seizure cluster.
On the other hand, I think that what he meant was "Astatic seizures".
That is actually a semiological term for drop-attacks.
Atonic seizures are represented by a reduction or abolishment of muscle tone on EMG, time-locked with an epileptic discharge on EEG.
This may represent the activation of negative motor areas of the cortex.
Astatic seizures could represent:
1) a tonic seizure that causes loss of balance and falls because of the sustained muscle tone.
2) a myoclonic seizure that causes a brief contraction and loss of balance.
3) An atonic seizure that causes a sustained loss of muscle tone and a fall.
4) a negative myoclonus that causes a brief loss of muscle tone.
Here is an interesting paper on the subject :
https://doi.org/10.1016/j.cortex.2012.04.014
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