A 17-year-old client is brought to the emergency department…

A 17-year-old client is brought to the emergency department after a first episode of generalized tonic–clonic movements witnessed at school. On arrival, the client is postictal but arousable; vital signs and blood glucose are within normal limits. A CT scan of the head without contrast and basic laboratory studies show no acute abnormalities. The provider plans additional testing to evaluate for an underlying seizure disorder. Which diagnostic test should the nurse anticipate?