Clinical Trial Details
— Status: Enrolling by invitation
Administrative data
| NCT number |
NCT05014841 |
| Other study ID # |
U01NS117765 |
| Secondary ID |
U01NS117765 |
| Status |
Enrolling by invitation |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
April 19, 2019 |
| Est. completion date |
August 31, 2025 |
Study information
| Verified date |
March 2024 |
| Source |
University of California, San Francisco |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
The overall goal of this study is to reveal the fundamental neural mechanisms that underlie
comprehension across human spoken languages. An understanding of how speech is coded in the
brain has significant implications for the development of new diagnostic and rehabilitative
strategies for language disorders (e.g. aphasia, dyslexia, autism, et alia). The basic
mechanisms underlying comprehension of spoken language are unknown. Researchers are only
beginning to understand how the human brain extracts the most fundamental linguistic elements
(consonants and vowels) from a complex and highly variable acoustic signal. Traditional
theories have posited a 'universal' phonetic inventory shared by all humans, but this has
been challenged by other newer theories that each language has its own unique and specialized
code. An investigation of the cortical representation of speech sounds across languages can
likely shed light on this fundamental question. Previous research has implicated the superior
temporal cortex in the processing of speech sounds. Most of this work has been entirely
carried out in English. The recording of neural activity directly from the cortical surface
from individuals with different language experience is a promising approach since it can
provide both high spatial and temporal resolution. This study will examine the mechanisms of
phonetic encoding, by utilizing neurophysiological recordings obtained during neurosurgical
procedures. High-density electrode arrays, advanced signal processing, and direct
electrocortical stimulation will be utilized to unravel both local and population encoding of
speech sounds in the lateral temporal cortex. This study will also examine the neural
encoding of speech in patients who are monolingual and bilingual in Mandarin, Spanish, and
English, the most common spoken languages worldwide, and feature important contrastive
differences of pitch, formant, and temporal envelope. A cross-linguistic approach is critical
for a true understanding of language, while also striving to achieve a broader approach of
diversity and inclusion in neuroscience of language.
Description:
Experimental approaches with significantly greater spatial and temporal resolution are
necessary to directly resolve, both local- and population- level, the contrastive encoding of
speech sounds. This study proposes an innovative methodological approach using customized
intracranial high-density electrode arrays to record neural activity directly from nonprimary
auditory cortex in patients undergoing clinical neurosurgical procedures (acute
intraoperative and chronic extraoperative). This approach overcomes obstacles in traditional
neuroimaging by offering high signal-to-noise recordings, unprecedented detailed
spatiotemporal resolution, and a large number of simultaneously recorded cortical sites in
awake, behaving subjects. The research study team will leverage the diversity of languages
spoken by patients that are treated at the large volume epilepsy and tumor brain mapping
programs at the University of California, San Francisco. They will examine cortical responses
to speech stimuli (natural speech corpora and control tokens) in Spanish, Mandarin, and
English speakers (monolingual and bilingual). They will also focus on encoding models in
three fundamental domains of acoustic-phonetic cues that are present in all languages: pitch,
formants, and amplitude envelope. The aims of this study seeks to determine how pitch cues
encode lexical tone processing in Mandarin (Aim 1), the cortical representation of vowels in
Spanish and English (Aim 2), and the encoding of the speech amplitude envelope in Spanish and
English (Aim 3). Together, these aims will elucidate mechanistic principles of speech
encoding in the human auditory cortex to understand what is shared and different across human
spoken languages. Abnormalities in these fundamental processes have been implicated in a host
of communication disorders such as dyslexia, developmental language disorder, central hearing
loss, and aphasia. These results should heavily impact current theories of speech processing
and, therefore, will have significant implications for understanding and remediating human
disorders across different languages.
