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Atypical absence
seizures
Atypical absence seizures
are similar to absence seizures but, as the name suggests, they
are unusual or not typical. The child will stare, as with
an absence seizure, but during an event he/she will be somewhat
responsive. Atypical absence seizures are similar to
absence seizures but may have more pronounced motor symptoms
such as tonic (stiffening) or clonic (jerking) spells or may
have automatisms (involuntary behaviours) as seen in complex
partial seizures. The EEG does not have the classic
three-per-second spike and wave pattern seen in simple absence
seizures. Like absence seizures, it can appear to
observers as though the child is daydreaming or switching off so
it may be hard to distinguish from the child's usual behaviour
and therefore difficult to detect. They can occur many times a
day and are often mistaken for daydreaming or look as though the
child is zoning out or "not with it".
In MAE, atypical absence seizures
may be just one manifestation of this mixed seizure disorder.
Atypical absence seizures often accompany clusters of
myoclonic and / or myoclonic-astatic seizures. If these seizures
occur frequently throughout the day, they can interrupt the
child's ability to function properly because his/her awareness
(and the brain's processing) is being constantly interrupted.
What happens?
Like all of the generalised
seizures, an atypical absence seizure starts suddenly and
without warning but the shift in consciousness may be so subtle
that it may be very difficult for an observer to detect when the seizure actually starts or
finishes. Similar to an absence seizure, the child displays a glazed look and stares.
However, unlike a simple absence seizure, the child may be
somewhat responsive and also have more pronounced motor symptoms
such as twitching of the mouth, eye blinking, mild head bobbing
which may give the observer a clue
that seizure activity is occurring. As is the case with all
generalised seizures, the child is momentarily unconscious
during the event so he/she doesn't know what is happening,
cannot recall anything, but in the case of an atypical absence
seizure he/she may be somewhat responsive to and aware of
his/her surroundings.
These events may be so
brief that they are observable only on the EEG which will show a
spike and wave pattern that distinguishes it from a simple
absence seizure. Sometimes the events may last 15-30 seconds or
perhaps longer and, to the observer, there may be an obvious
change in the child's state of consciousness. Being somewhat
responsive during a longer event, the child may have delayed
reactions, seem out of character, be easily confused or
agitated. The "somewhat responsive" feature of an an atypical
absence seizure may lead an observer to mistake the event for a
complex partial seizure.
Sometimes the seizures may go completely unnoticed because the
event is indistinguishable from the child's usual behaviour. When the seizure ends,
the child is usually alert
afterwards however he/she will have missed some of what is
happening around him/her.
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See
also Learning & behaviour
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See
also
Seizures - absence seizures
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See
also
Seizures -
Non-convulsive status epilepticus (NCSE)
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See
also
Safety -
Educating
your caregiver
What to do
Don't
- Restrain the child
- Act in a way that
could frighten the child, eg abrupt movements or shouting at
them
- Assume the person
is aware of what is happening or what has happened
- Give the child
anything to eat or drink until they are fully recovered
- Attempt to bring
them round
Call an
ambulance if....
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