Enhancing Letter-Speech Sound Learning and Reading Network Activation With Transcranial Electrical Stimulation
Transcranial Electrical Stimulation and the Reading Brain: Toward Novel Interventions for Reading Impairments
Silvia Brem
60 participants
Apr 23, 2026
INTERVENTIONAL
Conditions
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
Inclusion Criteria5
- Age 18-35
- All genders
- Written informed consent by the participant
- German speaking (native)
- Right-handed
Exclusion Criteria10
- 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
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Interventions
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.
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.
Locations(1)
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NCT07546292