taVNS for Letter Learning in Dyslexia

NCT06127550 — Not applicable, Suspended, 100 participants, University of Florida

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Effect of Non-invasive Vagus Nerve Stimulation on Letter Learning in Dyslexia

Registry	NCT06127550
Status	Suspended - Waiting on funding to support study
Phase	Not applicable
Study type	Interventional; randomized, parallel, masking: single, basic science
Enrollment	100 (Estimated)
Sponsor	University of Florida (Other)
Conditions	Dyslexia
Interventions	active taVNS, sham taVNS (Device)
Dates	start 2026-09-01 (estimated), primary completion 2028-08-01 (estimated), completion 2029-09-01 (estimated), first posted 2023-11-13, last updated 2026-05-28
Locations	1 site in United States

-Summary

This is a pilot study to establish feasibility of transcutaneous auricular vagus nerve stimulation (taVNS) for improving letter-learning in adolescents with dyslexia. The main goals of the study are to 1) evaluate whether children in this age range will tolerate low level stimulation over the course of multiple sessions, 2) determine whether low level taVNS improves novel letter learning in dyslexia, and 3) evaluate the effect of low level taVNS on the brain's response to letters. Participants will complete fMRI before training, immediately after training, and a few weeks after training ends. Training will consist of six 30-minute lessons during which participants will learn novel letter-sound relationships while receiving either active or sham taVNS. Researchers will compare stimulation conditions to determine effect of this device on learning and neural plasticity.

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+Arms and interventions

Arm	Type	Interventions	Description
Active taVNS	Experimental	Device: active taVNS	Participants will receive custom current at 5 Hz to the left auricular branch of the vagus nerve while learning new letter-sound relationships.
Sham taVNS	Sham comparator	Device: sham taVNS	Participants will undergo current thresholding but device will be turned off without their knowledge during the training.

active taVNS (Device): low level stimulation to the auricular branch of the vagus nerve
sham taVNS (Device): device placed with no current administered

+Outcome measures

Primary outcomes

Adverse events [4 weeks]: Frequency and severity of adverse events will be monitored and evaluated for severity and impact on attrition.
Compliance [4 weeks]: Percentage of the population that remains engaged in the study and completes all stimulation sessions.

Secondary outcomes

Letter ID [6 weeks]: Percent correct of learned letter-sound relationships
Decoding [6 weeks]: Percent correct of pseudowords read in 45 seconds
Automaticity [6 weeks]: This measure is based on a standardized measure for rapid letter naming in English (CTOPP-Rapid Automatized Naming) in which the participant is shown a grid of many letters in Hebrew and are asked to read the grid as quickly and accurately as possible while being timed.

Other outcomes

fMRI [6 weeks]: Strength of the brain's response to learned letters in the visual word form area

+Eligibility

Sex: All, ages: 10 Years to 12 Years, accepts healthy volunteers

Inclusion Criteria:

* Normal non-verbal IQ
* Reading scores above 90 on four single word reading measures (typical reader) OR reading scores below 90 on two or more single word reading measures (dyslexia) with or without ADHD

Exclusion Criteria:

* Neurological diagnoses (e.g., autism, epilepsy, etc.)
* Medications other than those prescribed for ADHD
* Nonverbal IQ below 80

+Locations (1)

Facility	City	Country	Status
University of Florida	Gainesville, Florida	United States