Role of Auditory Cortical Oscillations in Speech Processing and Dyslexia

Role of Auditory Cortical Oscillations in Speech Processing and Its Dysfunction in Dyslexia Through Transcranial Alternating Current Stimulation

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 Overview

• Status: Completed
• Conditions: Dyslexia
• Intervention / Treatment: Device: Transcranial alternating current stimulation

• Study Type: Interventional
• Enrollment (Actual): 30
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Switzerland
  • Geneva, Switzerland, 1202
    • Campus Biotech Geneva

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 65 years (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

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 Plan

How is the study designed?

Design Details

• Primary Purpose: BASIC_SCIENCE
• Allocation: NA
• Interventional Model: SINGLE_GROUP
• Masking: SINGLE

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
EXPERIMENTAL: tACS in individuals with and without dyslexia; 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.	Device: Transcranial alternating current stimulation; Focal transcranial stimulation over auditory cortex by means of 5 electrodes delivering an electric current (max. 2mA). In addition to active stimulation, also a placebo (sham) stimulation is employed as a control condition. All subjects included in the study receive all tACS stimulation conditions.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Measure low-gamma neural oscillations with electroencephalography recordings	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.	6 hour
Changes in linguistic performance through a battery of behavioral tests	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.	6 hours

Collaborators and Investigators

• Sponsor: University of Geneva, Switzerland
• Collaborators: Wyss Center for Bio and Neuroengineering
• Investigators: Principal Investigator: Anne-Lise Giraud, Prof., University of Genova

Publications and helpful links

General Publications

• Lehongre K, Ramus F, Villiermet N, Schwartz D, Giraud AL. Altered low-gamma sampling in auditory cortex accounts for the three main facets of dyslexia. Neuron. 2011 Dec 22;72(6):1080-90. doi: 10.1016/j.neuron.2011.11.002.

Study record dates

Study Major Dates

• Study Start (ACTUAL): September 1, 2016
• Primary Completion (ACTUAL): September 1, 2018
• Study Completion (ACTUAL): September 1, 2018

Study Registration Dates

• First Submitted: February 13, 2020
• First Submitted That Met QC Criteria: February 17, 2020
• First Posted (ACTUAL): February 20, 2020

Study Record Updates

• Last Update Posted (ACTUAL): February 20, 2020
• Last Update Submitted That Met QC Criteria: February 17, 2020
• Last Verified: February 1, 2020

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Mental Disorders; Nervous System Diseases; Neurologic Manifestations; Neurobehavioral Manifestations; Neurodevelopmental Disorders; Language Disorders; Communication Disorders; Learning Disabilities; Dyslexia
• Other Study ID Numbers: PHONOSTIM

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No