for people ages 18-70 (full criteria)
at San Francisco, California
study started
completion around
Principal Investigator
by Edward F Chang, MD
Headshot of Edward F Chang
Edward F Chang



The basic mechanisms underlying comprehension of spoken language are still largely unknown. Over the past decade, the study team has gained new insights to how the human brain extracts the most fundamental linguistic elements (consonants and vowels) from a complex and highly variable acoustic signal. However, the next set of questions await pertaining to the sequencing of those auditory elements and how they are integrated with other features, such as, the amplitude envelope of speech. Further investigation of the cortical representation of speech sounds can likely shed light on these fundamental questions. Previous research has implicated the superior temporal cortex in the processing of speech sounds, but little is known about how these sounds are linked together into the perceptual experience of words and continuous speech. The overall goal is to determine how the brain extracts linguistic elements from a complex acoustic speech signal towards better understanding and remediating human language disorders.


Intracranial high-density electrodes make it possible to record neural activity directly from the brain surface with unparalleled spatial and temporal resolution to unravel both local and population encoding of speech sounds. This study proposes to assess speech perception in patients who are undergoing surgery for seizure localization or awake intraoperative brain mapping. Electrode placement is based on the clinical needs of each patient. The research study team will examine the mechanisms of phonetic encoding to reveal both the organization of auditory speech feature selectivity and the distributed population-level processing that give rise to the emergent properties of spoken language perception. The aims of this study seeks to determine the cortical encoding of phonological sequencing (Aim 1), representation of amplitude landmark coding in speech (Aim 2), and the shared and distinct mechanisms for speech and music melody encoding (Aim 3). Together, these aims will advance our understanding of speech encoding in the human brain beyond consonants and vowels, addressing questions pertaining to sequencing, amplitude coding, and auditory specialization. These results should heavily impact current theories of speech processing and, therefore, will have significant implications for understanding and remediating human language disorders.


Epilepsy, Brain Tumor, Speech, Speech Tasks, Electrocorticography (ECoG) recording during Speech Tasks


You can join if…

Open to people ages 18-70

  • Participants with epilepsy or brain tumors at UCSF undergoing surgical electrode implantation for seizure localization or awake intraoperative brain mapping for resection of brain tumors or epilepsy and
  • Participants with electrodes implanted in at least two regions of interest who are willing and able to cooperate with study tasks.

You CAN'T join if...

  • Participants who lack capacity or decline to provide informed consent,
  • Participants who have significant cerebral lesions or
  • Participants with cognitive deficits that preclude reliable completion of study tasks.


  • UCSF
    San Francisco California 94143 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 by invitation only
Start Date
Completion Date
University of California, San Francisco
Study Type
Expecting 60 study participants
Last Updated