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

NCT07546292 | Not Yet Recruiting DMC

• 1 other identifier: BASEC2025-01540
• Study Type: interventional
• Target: 60
• Locations: 1 country
• Sites: 1

Brief 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).

Conditions

Dyslexia, Developmental; Reading; Dyslexia; Learning; Learning Disabilities

Keywords

Dyslexia; tRNS; transcranial electrical stimulation; non-invasive brain stimulation; neuromodulation; reading; functional magnetic resonance imaging; fMRI; audiovisual-learning

Outcome Measures

Primary Outcomes (2)

• Performance in the artificial orthography learning task

  Performance on the artificial orthography learning task and the artificial orthography reading fluency test will be compared between the stimulation and sham groups.

  At second session, up to 8 weeks after baseline

• fMRI activation and connectivity during print processing

  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.

  At baseline (Session 1) and at second session, up to 8 weeks after baseline

Secondary Outcomes (3)

• fMRI brain activation and connectivity in further fMRI tasks: audiovisual processing and naturalistic movie watching

  At baseline (Session 1) and at second session, up to 8 weeks after baseline

• Reading and reading-related behavioral measures

  At baseline (Session 1) and at second session, up to 8 weeks after baseline

• Performance in further cognitive tasks

  At baseline (Session 1) and at second session, up to 8 weeks after baseline

Study Arms (2)

Real Stimulation

EXPERIMENTAL

Participants will receive transcranial random noise stimulation (tRNS) applied to the left superior temporal gyrus.

Other: Transcranial random noise stimulation

Sham Stimulation

SHAM COMPARATOR

Participants in this group will serve as the control condition. The setup will be identical to the active stimulation group, but stimulation will be sham, such that no electrical current will be applied for the duration of the session.

Other: Sham Stimulation

Interventions

Transcranial random noise stimulation OTHER

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.

Real Stimulation

Sham Stimulation OTHER

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.

Sham Stimulation

Eligibility Criteria

• Age: 18 Years - 35 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Age 18-35
• All genders
• Written informed consent by the participant
• German speaking (native)
• Right-handed

You may not qualify if:

• 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

Sponsors & Collaborators

• Silvia Brem: lead
• Swiss National Science Foundation: collaborator

Study Sites (1)

University Hospital of Psychiatry

Zurich, Switzerland

Location

MeSH Terms

Conditions

Dyslexia; Learning Disabilities

Interventions

Transcranial Direct Current Stimulation

Condition Hierarchy (Ancestors)

Language Disorders; Communication Disorders; Neurobehavioral Manifestations; Neurologic Manifestations; Nervous System Diseases; Specific Learning Disorder; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Neurodevelopmental Disorders; Mental Disorders

Intervention Hierarchy (Ancestors)

Electric Stimulation Therapy; Therapeutics; Convulsive Therapy; Psychiatric Somatic Therapies; Behavioral Disciplines and Activities; Electroshock; Psychological Techniques

Central Study Contacts

Silvia Brem, Prof. Dr.

CONTACT

+41 (0)58 384 67 11; silvia.brem@kjpd.uzh.ch

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Purpose: BASIC SCIENCE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: Head - Developmental Cognitive Neuroscience Group

Study Record Dates

• First Submitted: April 9, 2026
• First Posted: April 22, 2026
• Study Start: April 1, 2026
• Primary Completion (Estimated): June 1, 2027
• Study Completion (Estimated): June 1, 2027
• Last Updated: April 22, 2026

Record last verified: 2026-04

Locations

CH (1)