During the eeg they usually flash lights, play sounds etc. to activate
various parts of the brain.   What it's recording is activity during the
test.  It doesn't measure anything that happens a day or 2 before.
  Possibly what they meant (above) was that one side showed epileptiform
waves (minor or other szr. electrical activity) versus the other side.  Many
of us have epileptiform activity in only one side or area of the brain.
That also is the area where we might get an aura or pre-seizure sensation --  
feeling of deja vu, jamais vu (where we are lost even if in a normally
familiar location),  strange taste or aroma that's not there -- lemon, eggy,
etc.   Doctor's can use those sorts of Auras to locate the most likely place
where the seizure launches from (the seizure focus).
   (I forgot to bring along your child's age. :-<  I'll look it up on older
post.  If they're too young to describe the feelings of auras above, the eeg
would still display the location of any electrical activity.   Also if they
happened to have szr. activity since birth, any feelings they have would
always be 'normal to them' since it's all that they've known?  So the
medical tests can be more help locating and assisting the Dr. in determining
how best to treat the szrs. and if they are happening only intermittently or
more frequently.)
  Another thing, but we haven't had a lot of people post recently -- a few
of the older posters said some of the pills or liquids (again depending on
the type of szr. and treatment recommended), had to be given at lower dose
but more Often during the day because younger folk digest foods and
medicines more rapidly than us olde timers.  So while I can use a Controlled
release pill 1-2x a day, others might need the lower dose 3-4x spaced out to
keep a stable blood level of the treatment.  I hope the Dr. is able to reach
that with you easily.  Maximum control is So neat, and it stops disruptive
smaller seizures from interfering with e.g. concentration, learning, memory
etc. that many of us still have.
     I hope he has success with whichever treatment they choose.  Keep us
posted with how you're doing.  That's what a support group is for.    G./

It is completely normal that you are worried about the outcome of the tests.
I would be worried as well! When your child has epilepsy, most of the times
this is captured by an EEG test. However, EEG tests are not always
conclusive I am affraid. That is why sometimes there is a need to do a
second test.

Normal electrical activity in the brain makes a recognizable pattern.
Seizures, which are rarely seen in EEG's, produce very specific, abnormal
patterns. Even without your child having a seizure, doctors can recognize
abnormal patterns that are markers for the risk of seizures. The patterns
are called different names. Common names for these abnormal patterns are
spikes, polyspikes, sharp waves and spike and wave complexes. These patterns
can tell your doctor a lot about your seizures, including the part of the
brain where your seizures start, and may even suggest which medicine might
be best for you.

When did your child had his first EEG test? Was that just after his seizure?
Did the seizure stop by itself or did the ER personell use some medication
to have it stop manually? If that is the case, then the EEG test may indeed
not be conclusive as it may not show the starting point of the epileptic
seizure (if this is caused by epilepsy of course). The starting point can be
anywhere in the brain: the right temporal lobe, the left temporal lobe or
both temporal lobes (which means you cannot really call it a starting point
anymore).

A normal EEG does not rule out epilepsy. There may have been no seizure
activity during the relatively short time the test was given, or the seizure
activity may be located in such a small area of the brain that the surface
electrodes failed to pick it up.

As was said before, with epilepsy one can have a complete normal live. The
only thing that a person with epilepsy must take into account is staying
alert and try to avoid any so called triggers like stress, lack of sleep,
too much alcohol, etc., etc. I was diagnosed with epilepsy when I was a baby
and I outgrown epilepsy when I was 2 or 3 years old, I got it back when I
was 9/10 or 11 years old (that appears to be normal) and outgrown it again
when I was approximately 15 years old (can't remember the exact dates). This
year I got it back because I was stupid enough to tend to forget to avoid
the triggers like too much alcohol, lack of sleep, too much stress, etc.
Luckily for me, I have been seizure free again with a low dose of medication
and live a completely normal live. My EEG showed abnormal or epileptic
activity throughout my whole brain which means I am diagnosed with primary
generalized epilepsy.

Hopefully your child will outgrown epilepsy as well or is being controlled
(seizure free) with medication with not so many side effects, etc. Anything
is possible here.