Role of Auditory Cortical Oscillations in Speech Processing and Dyslexia

Not Applicable

Completed

• Conditions: Dyslexia
• Interventions: Device: Transcranial alternating current stimulation

• Registration Number: NCT04277351
• Lead Sponsor: University of Geneva, Switzerland

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.

Detailed Description

Not available

Study Timeline

• Study Start: 2016-09-01
• Primary Completion: 2018-09-01
• Study Completion: 2018-09-01
• Status Verified: 2020-02
• Study First Submitted: 2020-02-13
• Study First Submitted QC: 2020-02-17
• Last Update Submitted: 2020-02-17
• Study First Posted: 2020-02-20
• Last Update Posted: 2020-02-20

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 30

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.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
tACS in individuals with and without dyslexia	Transcranial alternating current stimulation	Each participant in both the group of normo-readers and individuals with dyslexia receive all tACS stimulation conditions (fixed frequencies and sham) over different experimental days.

Primary Outcome Measures

Name	Time	Method
Changes in linguistic performance through a battery of behavioral tests	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	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.

Trial Locations

Locations (1)

Campus Biotech Geneva; 🇨🇭 Geneva, Switzerland