The purpose of this research is to learn more about Transcranial Cathodal Direct Current Stimulation (tDCS) and to see if it can help reduce the frequency of seizures in both adults and children with refractory focal epilepsy (epilepsy that cannot be well controlled by anti-seizure medication).

The use of tDCS is investigational in this study, which means that it is not approved by the FDA for the treatment of refractory focal epilepsy. Prior research suggests that daily tDCS may reduce the frequency of seizures in some patients with refractory focal epilepsy, although in some cases an increase in seizure frequency has also been observed. These changes may be due to tDCS decreasing the over-reaction of the region of your brain that your doctor believes causes your seizures.

There are a total of 14 visits, some of which may be conducted remotely. We expect that your involvement in this research will last approximately 6 months.

After you sign a consent document and agree to participate in this study, the following evaluations will be done:

1. A review of your medical history and medications. This includes a review of your seizure history and treatment.
2. We will ask you for a copy of a recent EEG and MRI. If your MRI is not suitable for the study, the study doctor may ask you to have another MRI.
3. A urine pregnancy test if you are female and able to have children.
4. A physical and neurological exam. 

You will be financially compensated to cover travel and hotel expenses.

The study staff is available via phone and email to answer questions if you are interested in participating in the trial or would like to learn more about the study.

Main inclusion criteria are:

* 9 years or older

* Focal epilepsy-not responsive to drug therapy