NCT06233513 · University of Wisconsin, Madison
Vowel Space Expansion Sensorimotor Adaptation
What this study is about
The purpose of this research study is to understand how the brain processes and controls speech in healthy people. The investigators are doing this research because it will help identify the mechanisms that allow people to perceive their own speech errors and to learn new speech sounds.
View original scientific description
The purpose of this research study is to understand how the brain processes and controls speech in healthy people. The investigators are doing this research because it will help identify the mechanisms that allow people to perceive their own speech errors and to learn new speech sounds. 117 participants will be enrolled into this part of the study and can expect to be on study between 1 day (Experiment 1) and 4 weeks (Experiment 2).
Interventions
BEHAVIORAL
Exp 3 Speaking Task
Participant will sit in front of a computer screen in a quiet room and to produce speech based on what is on the screen. Participant may see real words or nonsense words to read. Investigators may play sounds through headphones and ask the participant to repeat them. Participant speech will be recorded by a microphone. This task takes about one hour to complete.
Primary outcome measures
Average Vowel Spacing (AVS) Measured as the Mean of Pairwise Formant Distances Between Vowels
Time frame: up to 1 hour (Exp 1,3); eight visits of 1 hour each over 4 weeks (Exp 2)
AVS is a local measure of vowel spacing.
Quadrilateral Vowel Space Area (qVSA)
Time frame: up to 1 hour (Exp 1,3); eight visits of 1 hour each over 4 weeks (Exp 2)
qVSA measures the area (in Hz\^2) between the F1/F2 coordinates of the corner vowels. This is a global measure of working vowel space.
Intelligibility measured by Percent of words correctly identified by 5 independent transcribers
Time frame: up to 1 hour (Exp 1,3); eight visits of 1 hour each over 4 weeks (Exp 2)
Intelligibility is a perceptual measure. Four repetitions of each spoken production from each adaptation phase, as well as the minimal-pair neighbors from the calibration phase, will be identified by all transcribers. Because intelligibility in healthy speakers is expected to be near ceiling, speech signals will be masked by speech-shaped noise and delivered at 72 dB over closed-ear headphones. Signal-to-noise ratio will be determined prior to testing as the ratio where, on average, 50% of stimuli in the calibration phase are correctly identified. Transcribers will be native English speakers with no history of neurological/hearing disorders who pass a pure-tone hearing test.
Auditory acuity is measured as the average just noticeable difference (JND) along 4 vowel formant continua
Time frame: up to 1 hour (Exp 1,3); eight visits of 1 hour each over 4 weeks (Exp 2)
Auditory acuity is measured as the average just noticeable difference (JND) along 4 vowel formant continua: /i/-/ɪ/, /ɛ/-/æ/, /u/-/ʊ/, and /ɑ/-/ʌ/. Acuity will be measured at continua midpoint (across-category acuity) and at the four corner vowel endpoints (within-category acuity). JNDs will be measured through a 4-interval, 2-alternative forced choice task (AABA or ABAA) via a staircase procedure.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- English-speaking adults
- normal hearing and speech
- no history of stroke or neurological conditions
Exclusion criteria
- Native language other than English
- Any neurological disorders other than the disorder of interest
- Any history of hearing disorders
- Uncorrected vision problems that prevent participants from seeing visually-presented stimuli
- Significant cognitive impairments that prevent participants from carrying out the task or from giving informed consent
- Vulnerable populations (minors and prisoners)
Where
- Madison, Wisconsin
Collaborators
National Institute on Deafness and Other Communication Disorders (NIDCD)
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Apr 9, 2026 · Source of record for eligibility and locations