taVNS for Letter Learning in Dyslexia

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

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.

Study Overview

• Status: Suspended
• Conditions: Dyslexia
• Intervention / Treatment: Device: active taVNS; Device: sham taVNS

• Study Type: Interventional
• Enrollment (Estimated): 100
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Florida
    • Gainesville, Florida, United States, 32610
      • University of Florida

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: Yes

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: 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.	Device: active taVNS; low level stimulation to the auricular branch of the vagus nerve
Sham Comparator: Sham taVNS; Participants will undergo current thresholding but device will be turned off without their knowledge during the training.	Device: sham taVNS; device placed with no current administered

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Adverse events	Frequency and severity of adverse events will be monitored and evaluated for severity and impact on attrition.	4 weeks
Compliance	Percentage of the population that remains engaged in the study and completes all stimulation sessions.	4 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Letter ID	Percent correct of learned letter-sound relationships	6 weeks
Decoding	Percent correct of pseudowords read in 45 seconds	6 weeks
Automaticity	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.	6 weeks

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
fMRI	Strength of the brain's response to learned letters in the visual word form area	6 weeks

Collaborators and Investigators

• Sponsor: University of Florida

Study record dates

Study Major Dates

• Study Start (Estimated): September 1, 2026
• Primary Completion (Estimated): August 1, 2028
• Study Completion (Estimated): September 1, 2029

Study Registration Dates

• First Submitted: October 27, 2023
• First Submitted That Met QC Criteria: November 7, 2023
• First Posted (Actual): November 13, 2023

Study Record Updates

• Last Update Posted (Actual): May 28, 2026
• Last Update Submitted That Met QC Criteria: May 26, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Specific Learning Disorder; Neurologic Manifestations; Nervous System Diseases; Mental Disorders; Neurobehavioral Manifestations; Neurodevelopmental Disorders; Communication Disorders; Language Disorders; Learning Disabilities; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Dyslexia
• Other Study ID Numbers: IRB202301883

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: No