Transcranial Direct Current Stimulation in the Treatment of Dyslexia.

Study Overview
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Brief Summary
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The present study grounds on the absence of evidence-based treatment in individuals with dyslexia. At this topic, the present study will explore the potential effect of transcranial direct current stimulation (tDCS) over parieto-occipital brain regions, cerebral areas usually disrupted in individuals with dyslexia. tDCS will be administered without concomitantly training. Therefore, the investigators hypothesized that active tDCS over parieto-occipital areas will enhance reading skills in children and adolescents with dyslexia. On the contrary, sham tDCS (placebo) over parieto-occipital areas will not have significant effect on reading. Further, both active and sham tDCS will be safe and well-tolerated.

Detailed Description
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The study design is randomized stratified, cross-over, double-blind, placebo-controlled. Children and adolescents with dyslexia will be selected and randomly assigned to two different groups: 1. Active tDCS over parieto-occipital areas + sham tDCS over parieto-occipital areas (Active-Sham tDCS); 2. Sham tDCS over parieto-occipital areas + active tDCS over parieto-occipital areas (Sham-Active tDCS). In this project, the investigators will work to understand whether a brain-based intervention, with the use of tDCS without combined training, can enhance reading in individuals with dyslexia. The protocol will allow the investigators to: Testing the efficacy of stand-alone tDCS in enhancing reading in individuals with dyslexia; Testing the critical role of brain regions (parieto-occipital areas) usually involved in reading and disrupted in dyslexia; Predicting outcomes based on reading-related skills; Investigating the safety and tolerability of tDCS; The overarching goal is to provide a scientific foundation for devising new rehabilitation strategies in dyslexia.

Official Title
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Transcranial Direct Current Stimulation in the Treatment of Dyslexia: a Randomized Double-blind Study.

Conditions
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Dyslexia

Intervention / Treatment
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* Device: Active tDCS
* Device: Sham tDCS


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Children and adolescents with dyslexia (DSM-5, APA 2013) IQ ≥ 85 Exclusion Criteria: Having a comorbidity with an important medical conditions; Having neurological diseases; Having Epilepsy o family history of epilepsy; Receiving a treatment for dyslexia in the previous three months before the baseline screening;

Ages Eligible for Study
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Minimum Age: 9 Years
Maximum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Active-Sham tDCS<br>Each tDCS sessions will be delivered for 5 days for a total of non consecutive two weeks. The first session will be active tDCS and two months after, a sham tDCS will follow. | Device: Active tDCS<br>* Active tDCS will be delivered to parieto-occipital areas for five consecutive days. tDCS will be delivered by a battery driven, direct current stimulator through a pair of saline-soaked sponge electrodes kept firm by elastic bands. The electrodes will be placed on the left (anodal) and right (cathodal) parieto-occipital areas, PO7 and PO8 position according to the 10-20 international EEG system for electrode placement. Stimulation intensity will be set at 1 milliampere (mA), the duration of stimulation will be 20 min.<br>* Other names: Brainstim Active tDCS;Device: Sham tDCS<br>* Sham tDCS will be delivered to parieto-occipital areas for five consecutive days. tDCS will be delivered by a battery driven, direct current stimulator through a pair of saline-soaked sponge electrodes kept firm by elastic bands. The electrodes will be placed on the left (anodal) and right (cathodal) parieto-occipital areas, PO7 and PO8 position according to the 10-20 international EEG system for electrode placement. Stimulation intensity will be set at 1 milliampere (mA), but the current will be applied for 30 s and will be ramped down without the participants awareness.<br>* Other names: Brainstim Sham tDCS;|
| Active Comparator: Sham-Active tDCS<br>Each tDCS sessions (sham tDCS and active tDCS) will be delivered for 5 days for a total of non consecutive two weeks. The first session will be sham tDCS and two months after, an active tDCS will follow. | Device: Active tDCS<br>* Active tDCS will be delivered to parieto-occipital areas for five consecutive days. tDCS will be delivered by a battery driven, direct current stimulator through a pair of saline-soaked sponge electrodes kept firm by elastic bands. The electrodes will be placed on the left (anodal) and right (cathodal) parieto-occipital areas, PO7 and PO8 position according to the 10-20 international EEG system for electrode placement. Stimulation intensity will be set at 1 milliampere (mA), the duration of stimulation will be 20 min.<br>* Other names: Brainstim Active tDCS;Device: Sham tDCS<br>* Sham tDCS will be delivered to parieto-occipital areas for five consecutive days. tDCS will be delivered by a battery driven, direct current stimulator through a pair of saline-soaked sponge electrodes kept firm by elastic bands. The electrodes will be placed on the left (anodal) and right (cathodal) parieto-occipital areas, PO7 and PO8 position according to the 10-20 international EEG system for electrode placement. Stimulation intensity will be set at 1 milliampere (mA), but the current will be applied for 30 s and will be ramped down without the participants awareness.<br>* Other names: Brainstim Sham tDCS;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Non-word reading speed | The proportion of patients with change of at least 0.06 sill/sec in the non-word reading speed following Active tDCS sessions than after Sham tDCS sessions both in ActiveSham tDCS and ShamActive tDCS. | up to one month after the end of the intervention | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Non-word reading accuracy | The proportion of patients with change in the non-word reading accuracy following Active tDCS sessions than after Sham tDCS sessions both in ActiveSham tDCS and ShamActive tDCS. | up to one month after the end of the intervention | 
| Word reading speed | The proportion of patients with change in the word reading speed following Active tDCS sessions than after Sham tDCS sessions both in ActiveSham tDCS and ShamActive tDCS. | up to one month after the end of the intervention | 
| Word reading accuracy | The proportion of patients with change in the word reading accuracy following Active tDCS sessions than after Sham tDCS sessions both in ActiveSham tDCS and ShamActive tDCS. | up to one month after the end of the intervention | 
| Text reading speed | The proportion of patients with change in the text reading speed following Active tDCS sessions than after Sham tDCS sessions both in ActiveSham tDCS and ShamActive tDCS. | up to one month after the end of the intervention | 
| Text reading accuracy | The proportion of patients with change in the text reading accuracy following Active tDCS sessions than after Sham tDCS sessions both in ActiveSham tDCS and ShamActive tDCS. | up to one month after the end of the intervention | 
| Verbal and visuo-spatial n-back | The proportion of patients with change in the index of verbal and visuo-spatial working memory (more score means better outcome) following Active tDCS sessions than after Sham tDCS sessions both in ActiveSham tDCS and ShamActive tDCS. | up to one month after the end of the intervention | 
| Phoneme Blending | The proportion of patients with change in the index of phoneme blending (more score means better outcome) following Active tDCS sessions than after Sham tDCS sessions both in ActiveSham tDCS and ShamActive tDCS. | up to one month after the end of the intervention | 
| Rapid Automatized Naming of color and letters | The proportion of patients with change in the accuracy and speed of Rapid Automatized Naming of color and letters following Active tDCS sessions than after Sham tDCS sessions both in ActiveSham tDCS and ShamActive tDCS. | up to one month after the end of the intervention | 
| Lexical Decision | The proportion of patients with change in the accuracy and speed of Lexical decision following Active tDCS sessions than after Sham tDCS sessions both in ActiveSham tDCS and ShamActive tDCS. | up to one month after the end of the intervention | 
| Questionnaire of safety and tolerability (Questionnaire of adverse effect) | The proportion of patients with change in the questionnaire of safety and tolerability (Questionnaire of adverse effect; Brunoni et al., 2011) following Active tDCS sessions will be the same than after Sham tDCS sessions both in ActiveSham tDCS and ShamActive tDCS. | up to one month after the end of the intervention | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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tDCS, transcranial direct current stimulation, transcranial electric stimulation, developmental dyslexia, specific learning disorders, treatment