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.

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.

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.