Enhancing Letter-Speech Sound Learning and Reading Network Activation With Transcranial Electrical Stimulation

NCT07546292 · tracked via the Priya Life Science Switzerland tracker

Sponsor

Silvia Brem

Phase

Not applicable

Started

2026-04-23

Last updated

2026-05-22

Condition(s) studied

Dyslexia, DevelopmentalReadingDyslexiaLearningLearning Disabilities

Investigational drug(s) / intervention(s)

Transcranial random noise stimulationSham Stimulation

Transcranial random noise stimulation: Participants will receive high-frequency tRNS (max. 1.5 mA) applied to the left superior temporal gyrus. A high-definition setup (3x1 electrodes) will be used to achieve more focal stimulation. Stimulation will be applied during an artificial orthography learning task with simultaneous fMRI acquisition.

Sham Stimulation: Participants will also have electrodes placed on their scalp. The setup is programmed to induce a short ramp-up of the chosen electrical current followed by a ramp-down at the beginning and at the end of the stimulation. In between, no current will be applied. Sham stimulation will be applied during an artificial orthography learning task with simultaneous fMRI acquisition.

Study summary

This study investigates the effects of transcranial electrical stimulation (tES) on the brain and its potential to enhance reading-related learning. Adult participants with a range of reading abilities will receive transcranial random noise stimulation (tRNS) while they perform an artificial orthography learning task. This task simulates letter-speech sound learning, an important first step during reading acquisition known to be impaired in individuals with developmental dyslexia. The effects of the intervention will be assessed using both behavioral measures and functional magnetic resonance imaging (fMRI).

Eligibility

Sex

ALL

Min age

18 Years

Max age

35 Years

Healthy volunteers

Accepted

Inclusion Criteria: * Age 18-35 * All genders * Written informed consent by the participant * German speaking (native) * Right-handed Exclusion Criteria: * Diagnoses of neurological disorders, intellectual disabilities, or psychiatric disorders (We do not exclude participants with common comorbidities of dyslexia, specifically dyscalculia, Attention Deficit/Hyperactivity Disorder, or Autism Spectrum Disorders) * History of any acquired brain damage or evidence of fetal alcohol syndrome * Hearing problems and vision problems that cannot be corrected * Inability to follow procedures or understand the instructions given in (Swiss-)German * Current use of psychoactive medications or substances, or a history of substance abuse that may affect brain function, performance or MRI signal quality * A nonverbal IQ \< 80 * Having previously participated in a transcranial electrical stimulation study * Knowledge to read or write in a language using foreign letters (i.e., different from the Latin alphabet) * Contraindications to brain stimulation or MRI, such as: History of epilepsy or severe migraine; Skull breach such as craniotomy; Wearing neurostimulators or cardiac pacemakers; Wearing hearing aid devices or cochlear implants, which are not MR safe; Having metal pieces in their body (e.g., piercings that cannot be removed and contain metal, screws or plates from surgical operations, wounds from metal splinters or similar); Claustrophobia or problems lying in the scanner (e.g., pain, anxiety); Previous surgery on the head or heart; Being pregnant (a pregnancy test will be conducted at the MR center before the measurement if a female participant suspects she might be pregnant or is uncertain about her pregnancy status according to the Swiss Ethics Leitlinie: https://swissethics.ch/assets/pos\_papiere\_leitfaden/20110906\_kek\_mri.pdf); Having problems lying still (strong cold, tremor, etc.); Wearing non-removable dental braces

Primary outcome measure(s)

Performance in the artificial orthography learning task — At second session, up to 8 weeks after baseline
Performance on the artificial orthography learning task and the artificial orthography reading fluency test will be compared between the stimulation and sham groups.
fMRI activation and connectivity during print processing — At baseline (Session 1) and at second session, up to 8 weeks after baseline
fMRI activation and connectivity of the posterior superior temporal gyrus and other regions of the reading and audiovisual learning networks will be compared before, during and after transcranial electrical stimulation (tES). The fMRI tasks performed in the second session include artificial orthography learning and explicit print processing (lexical decision task), whereas implicit print processing (one-back task) is performed both at baseline and in the second session. These changes in activation and connectivity will be compared between the stimulation group and the sham group.

Trial sites (1)

Facility	City	Region	Status
University Hospital of Psychiatry	Zurich	Switzerland	Recruiting

Official registry record

This page summarises publicly available registry data for informational purposes — not medical advice. Eligibility is determined by each study team; patients should discuss participation with their clinician.

View NCT07546292 on ClinicalTrials.gov ↗ ← All trials in Switzerland