Understanding Speech Control in Healthy Adults

This study, called "Vowel Space Expansion Sensorimotor Adaptation," aims to understand how healthy brains control speech. Researchers want to learn how people notice their own speech errors and learn new sounds. You would participate in speaking tasks, which involve reading words (real or nonsense) and repeating sounds played through headphones. The study will measure how clearly you speak (intelligibility) and changes in your vowel sounds. They plan to enroll 117 English-speaking adults with normal hearing and speech, and no history of stroke or other neurological conditions. The study is looking for healthy volunteers to help understand these basic processes.

Study design
This is an interventional study with planned enrollment of 117 participants. It involves different experiments to understand speech control.
What's involved
You would sit in front of a computer screen and produce speech. This could involve 1-hour visits for one day, or eight 1-hour visits over 4 weeks, depending on the experiment.
Compensation
Not stated in the trial record.
Follow-up
Your speech will be measured at up to 1 hour or over 4 weeks, depending on the experiment.

AI-generated from the public study record. Only the study team can confirm whether you're eligible — confirm details with them before making decisions.

NCT06233513

Vowel Space Expansion Sensorimotor Adaptation

Recruiting
NAAges 18+InterventionalBasic science
University of Wisconsin, Madison
~117 participants
Updated 2026-07-30 on ClinicalTrials.gov
What's tested:Exp 3 Speaking Task

At a glance

Recruiting sites
1 of 1 listed site is recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Average Vowel Spacing (AVS) Measured as the Mean of Pairwise Formant Distances Between Vowels
Measured over up to 1 hour (Exp 1,3); eight visits of 1 hour each over 4 weeks (Exp 2)
+3 more outcomes measured
Speech

NCT06233513

Where you'd take part

This study runs at 1 site. They're the same protocol — you choose where, and that choice sets who your contact draft is addressed to.

  • University of Wisconsin

    Madison, Wisconsinstudy coordinator listed

    Recruiting

Sites open and close at different times, so the status above is per site — it can differ from the study's overall status.

  • Carrie Niziolek, PhD · PRINCIPAL_INVESTIGATOR · University of Wisconsin, Madison

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Eligibility criteria

Inclusion

English-speaking adults
normal hearing and speech
no history of stroke or neurological conditions

Exclusion

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)
  • Average Vowel Spacing (AVS) Measured as the Mean of Pairwise Formant Distances Between Vowelsup 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)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 transcribersup 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 continuaup 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.