Role of Auditory Cortical Oscillations in Speech Processing and Its Dysfunction in Dyslexia Through Transcranial Alternating Current Stimulation
Trial Snapshot
- Phase
- Not Applicable
- Status
- Completed
- Sponsor
- Enrollment
- 30
- Locations
- 2
- Primary Endpoint
- Changes in linguistic performance through a battery of behavioral tests
Study Overview
Brief Summary
This study aims at investigating the role of low-gamma activity in phonemic encoding and its implication in dyslexia. Indeed, a phonological deficit, i.e. a difficulty in perceiving the sounds of speech, is strongly suspected in dyslexia but has never been conclusively associated with a specific underlying mechanism.
The study employs transcranial alternating current stimulation in adults with and without dyslexia to exploit the effect of the stimulation on phonemic processing and neural activity measured with electroencephalography. In doing so, it would be possible to establishing a causal link between gamma oscillations and the phonological deficit in dyslexia.
Study Design
- Study Type
- Interventional
- Allocation
- Na
- Intervention Model
- Single Group
- Primary Purpose
- Basic Science
- Masking
- Single (Participant)
Masking Description
One of three different tACS conditions is administered to all participant during three experimental days. The conditions differ in the frequency of stimulation (condition 1 and 2) and in whether the stimulation is active or faked (sham). The order of the three stimulation conditions is counterbalanced across participants, who are not aware of which tACS condition they are undergoing.
Eligibility Criteria
- Ages
- 18 Years to 65 Years (Adult, Older Adult)
- Sex
- All
- Accepts Healthy Volunteers
- Yes
Inclusion Criteria
- •18-65 years old;
- •French native speakers;
- •normally-hearing;
- •intellectual quotient (IQ) around average;
- •for the dyslexia group: previous diagnosis of dyslexia as assessed by a speech therapist.
Exclusion Criteria
- •Presence of metal or electronic implants in the brain/skull;
- •Presence of metal or electronic device at other in other parts of the body;
- •Have experienced a seizure or a loss of consciousness or a severe head trauma;
- •Severe brain related illness ;
- •Intake of central nervous system-effective medication;
- •Pregnant and nursing women;
- •Relatives affected by epilepsy.
Outcomes
Primary Outcomes
Changes in linguistic performance through a battery of behavioral tests
Time Frame: 6 hours
Measurement of phonemic and syllabic processing (pseudoword repetition and spoonerism test), and reading (reading a 3 min. text, both accuracy and reading speed are considered) skills. These tests are repeated before, after and 1h after the tACS stimulation.
Measure low-gamma neural oscillations with electroencephalography recordings
Time Frame: 6 hour
Auditory-steady state responses to auditory stimuli are measured to assess specific differences between individuals with dyslexia and normo-readers, and between the different tACS stimulation conditions before, after and 1h after the 20 min. tACS stimulation. These neural correlated are estimated by considering the power of EEG signal at the frequency used to modulate the auditory stimuli.
Secondary Outcomes
No secondary outcomes reported
Investigators
Anne-Lise Giraud
Professor
University of Geneva, Switzerland