Could an eeg done in a hosital in 1998 have been wrong showing epilepsy if i was on a sleeping pill with barbituates?

Unknown: A lot can change in 14 years.A sleeping pill would tend to mask rather than show epilepsy.

Maybe: In the proper clinical setting many tests approach 100% accuracy when clearly abnormal, however, no test is 100% accurate and many tests have a much lower accuracy rate. It may be worthwhile repeating the test under more controlled circumstances. Barbiturates can certainly affect an eeg test.