for people ages 18 years and up (full criteria)
at San Francisco, California and other locations
study started
completion around
Principal Investigator
by Edward F Chang, MD
Headshot of Edward F Chang
Edward F Chang



Neuropsychiatric disorders are a leading cause of disability worldwide with depressive disorders being one of the most disabling among them. Also, millions of patients do not respond to current medications or psychotherapy, which makes it critical to find an alternative therapy. Applying electrical stimulation at various brain targets has shown promise but there is a critical need to improve efficacy.

Given inter- and intra-subject variabilities in neuropsychiatric disorders, this study aims to enable personalizing the stimulation therapy via i) tracking a patient's own symptoms based on their neural activity, and ii) a model of how their neural activity responds to stimulation therapy. The study will develop the modeling elements needed to realize a model-based personalized closed-loop system for electrical brain stimulation to achieve this aim.

The study will provide proof-of-concept demonstration in epilepsy patients who already have intracranial electroencephalography (iEEG) electrodes implanted for their standard clinical monitoring unrelated to this study, and who consent to being part of the study.


The investigators will conduct the study for each subject during their stay in the epilepsy monitoring unit (EMU), which is dictated purely based on their standard clinical needs unrelated to our study. iEEG will be recorded from each patient throughout their stay in the EMU, during which the self-reports from them will be also intermittently collected using validated questionnaires that relate to depression symptoms.

The investigators will build decoders that can track these depression symptoms from iEEG activity. The investigators will also apply electrical stimulation to learn a personalized input-output model that predicts the iEEG response to ongoing stimulation. The resulting personalized decoder and the input-output model will be combined to achieve model-based personalization of stimulation therapy.

Successful completion of this study will help enable precisely-tailored deep brain stimulation therapies across diverse conditions and have a broad public health impact.


Medication Refractory Epilepsy Patients With Electrodes Already Implanted Based on Clinical Criteria for Standard Monitoring, deep brain stimulation, model-based stimulation, closed-loop stimulation, neural biomarkers of depression, neurotechnology, neuropsychiatric disorders, depression, brain-machine interface, Drug Resistant Epilepsy, model-based electrical brain stimulation


You can join if…

Open to people ages 18 years and up

  • Patients being evaluated for surgical treatment of medication refractory epilepsy and brain tumors will be studied. ONLY patients with electrodes implanted based on clinical criteria to locate their seizure focus will be studied. Most patients are healthy adults, outside of their epilepsy and/or brain tumor.
  • Subjects >= 18 are only included in this study.
  • All patients with the above conditions and with implanted electrode arrays who are willing to participate and able to cooperate and follow research instructions will be recruited. However, analysis of research recording data will focus on those subjects with an IQ >= 80, with no impairments of reading, naming, or articulation (to minimize confounds such as abnormal language processing that may affect their self-reporting with the questionnaire), and with no cerebral pathology affecting the cortical regions from which recordings are made.

You CAN'T join if...

  • Subjects < 18 years old will be excluded from this study due to the high concordance of developmental disorders (cognitive and language-related) in pediatric epilepsies.
  • There will be no involvement of special classes of subjects, such as fetuses, neonates, pregnant women, children, prisoners, institutionalized individuals, or others who may be considered vulnerable populations.
  • Patients who are unable to give informed consent due to a brain disorder will be excluded from the study, as it is very likely that they would be unable to carry out the tasks demanded by the study.


  • UCSF accepting new patients
    San Francisco California 94143 United States
  • University of Southern California accepting new patients
    Los Angeles California 90089 United States

Lead Scientist at UCSF

  • Edward F Chang, MD
    Dr. Edward Chang is a neurosurgeon who treats patients with epilepsy, brain tumors, and cranial nerve nerve compression syndromes such as trigeminal neuralgia and hemifacial spasm. He is Chairman of the Department of Neurological Surgery at UCSF. Dr Chang specializes in advanced brain mapping methods to preserve crucial areas for speech and motor functions in the brain.


accepting new patients
Start Date
Completion Date
University of Southern California
Study Type
Expecting 25 study participants
Last Updated