Hi, My Daughter Has Been C/o Dizziness That Comes On

Hi, my daughter has been c/o dizziness that comes on and last for anywhere from 30 sec. duration to up to 3 minutes. Sometimes her words for just that amount of time don't make total sense. Then she comes out of it. I took her to ER in Jefferson City, Mo and she stayed overnite, CT and MRI were done and EEG all negative. She is an environmental engineer and her mind is fully absorbed telecommuting for a corporation in NH. She is very good at what she does and has a large client base. The neurologist that was on call told her that until we ruled out a seizure dx, she should not drive for 6 months.
Her cholestral and trigly. were very high, no cardiac cath. done, just CT of head and neck.
Can you give us some insights to work with for a differential dx., since to not be able to drive to a/p or to job sites would be detrimental to her and she is supporting her daughter as well as nieces and nephews..
I was thinking maybe it is inner ear(lots of ear infections when younger). Maybe she has some blockage in the arteries, why is the neurologists not following up on what else it could be? She says she has to rule it out(seizures). She has her on sz. med to take now and primary doc took her off Wellbutrin (she has quit smoking!!), he was thinking that dizziness, and szs could occur as side effect. Any ideas? So thankful!