Your wife probably had all the usual tests while hospitalized. Hopefully she was given a thorough Neurological exam along with a complete medical history EEG, MRI plus blood tests are the most usual first step tests. CT, PET are sometimes done and rarely specialized DNA tests on certain chromosomes are preformed. Doctors sometimes order various heart tests as well and possibly an MRA which is done in a MRI scanner which shows the arteries and blood flow in the brain. Sometimes a patient may be referred to an Endocrinologist for complete chemical and/or hormonal testing.
Unfortunately, most patients are diagnosed with idiopathic (unknown) Epilepsy. My diagnosis is idiopathic Generalized Epilepsy. There are many Epilepsy syndromes and at least 35 different medications so it can take a long time to find the right drug cocktail. Hopefully your wife will be in the 70% who are controlled on medication. Good luck to you both