Has any one heard of seizures that cause visual hallucination in a person?

I am asking as I just spent twelve long hours in the emergency room with my three year old niece that was having hallucinations of rats being in her hair and snakes crawling all over body her body (at one point she even thought her arm had fallen off) and nothing her mother or I did could comfort her when the episodes were taking place.... which happened from 10 am that morning until 12 mid night that night - she went to sleep for some well needed rest after she was given medicine that induced sleep.

The doctor at the hospital did lab work with a urine test and a cat scan to rule out brain trauma and any accidental drug intake and they both came back negative... we are now waiting on an apt with a Pediatric Neurologist to have an EGG performed to see if my niece may be suffering from a rare seizure disorder that causes visual hallucinations during the moment the seizure is occurring.

The waiting is killing us.... and while my niece seems 90% her self today we are still concerned with the fact that this could happen again until the cause is determined and treated correctly.