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.
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: 1. Testing the efficacy of stand-alone tDCS in enhancing reading in individuals with dyslexia; 2. Testing the critical role of brain regions (parieto-occipital areas) usually involved in reading and disrupted in dyslexia; 3. Predicting outcomes based on reading-related skills; 4. Investigating the safety and tolerability of tDCS; The overarching goal is to provide a scientific foundation for devising new rehabilitation strategies in dyslexia.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
28
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.
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.
Bambino Gesù Hospital and Research Institute
Roma, Italy
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.
Time frame: up to one month after the end of the intervention
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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: up to one month after the end of the intervention
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