The present study grounds on the absence of evidence-based treatment in individuals with developmental dyslexia (DD). At this topic, the present study will explore the potential effect of transcranial random noise stimulation (tRNS) and transcranial direct current stimulation (tDCS) over bilateral temporo-parietal cortex (TPC), cerebral areas usually disrupted in individuals with DD. The investigators hypothesized that active tRNS and tDCS over TPC will boost reading skills in children and adolescents with DD. On the contrary, sham (placebo) tRNS and tDCS over TPC will not have significant effect in improving reading skills. Further, both active and sham tRNS and tDCS will be safe and well tolerated.
The study design is within-subject, randomized stratified, double blind, placebo-controlled. A group of children and adolescents with DD will be selected and exposed to three different conditions with an interval-session of at least 6 days: 1. tRNS over bilateral TPC; 2. anodal tDCS over left TPC (cathode over right TPC); 3. sham tRNS or tDCS. During stimulation (both real and sham), participants will undergo a concomitant reading task. In this project, the investigators will work to understand whether a brain-based intervention, with the use of tRNS and tDCS, can improve the outcome of individuals with DD. The protocol will allow the investigators to: * comparing the efficacy of tDCS and tRNS over TPC in improving reading abilities, * comparing the safety and tolerability of tDCS and tRNS in children and adolescents. The investigator's overarching goal is to provide a scientific foundation for devising new rehabilitation strategies in DD, based on the two most used brain stimulation techniques in pediatric population.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
24
Active tDCS will be delivered over TPC for a stimulation session. The anodal electrode will be placed on the left TPC, T7/TP7 position according to the 10-20 International EEG 10-20 System for electrode placement. The cathodal electrode will be placed on the right TPC, T8/TP8 position. Intensity will be set at 1 mA, the duration of stimulation will be 20 min.
Active tRNS will be delivered to bilateral TPC for a stimulation session. The electrodes will be placed on the left and right TPC, respectively T7/TP7 and T8/TP8 position, at 0.75 mA (100-500 Hz) for 20 min.
Sham tRNS or tDCS will be delivered over bilateral TPC for a stimulation session. The same electrodes placement as well as the stimulation set-up will be used as in the active stimulation conditions, 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
Text reading accuracy (Experimental reading task)
Change from baseline in text reading accuracy during Active tDCS and Active tRNS sessions than during Sham tDCS and Sham tRNS sessions. Text reading accuracy is considered as the percentage (%) of accuracy and computed as the ratio between the number of correctly read stimuli and the total number of stimuli presented multiplied by 100.
Time frame: during procedure
Text reading speed (Experimental reading task)
Change from baseline in text reading speed during Active tDCS and Active tRNS sessions than during Sham tDCS and Sham tRNS sessions. Text reading speed is considered as the syllables/seconds ratio and calculated dividing the total number of syllables pronounced by the total time spent to complete the reading (in seconds).
Time frame: during procedure
Experimental reading task: high-frequency word reading accuracy
Change from baseline in high-frequency word reading accuracy during Active tDCS and Active tRNS sessions than during Sham tDCS and Sham tRNS sessions. High-frequency word reading accuracy is considered as the percentage (%) of accuracy and computed as the ratio between the number of correctly read stimuli and the total number of stimuli presented multiplied by 100.
Time frame: during procedure
Experimental reading task: high-frequency word reading speed
Change from baseline in high-frequency word reading speed during Active tDCS and Active tRNS sessions than during Sham tDCS and Sham tRNS sessions. High-frequency word reading speed is considered as the syllables/seconds ratio and calculated dividing the total number of syllables pronounced by the total time spent to complete the reading (in seconds).
Time frame: during procedure
Experimental reading task: low-frequency word reading accuracy
Change from baseline in low-frequency word reading accuracy during Active tDCS and Active tRNS sessions than during Sham tDCS and Sham tRNS sessions. Low-frequency word reading accuracy is considered as the percentage (%) of accuracy and computed as the ratio between the number of correctly read stimuli and the total number of stimuli presented multiplied by 100.
Time frame: during procedure
Experimental reading task: low-frequency word reading speed
Change from baseline in low-frequency word reading speed during Active tDCS and Active tRNS sessions than during Sham tDCS and Sham tRNS sessions. Low-frequency word reading speed is considered as the syllables/seconds ratio and calculated dividing the total number of syllables pronounced by the total time spent to complete the reading (in seconds).
Time frame: during procedure
Experimental reading task: non-word reading accuracy
Change from baseline in non-word reading accuracy during Active tDCS and Active tRNS sessions than during Sham tDCS and Sham tRNS sessions. Non-word reading accuracy is considered as the percentage (%) of accuracy and computed as the ratio between the number of correctly read stimuli and the total number of stimuli presented multiplied by 100.
Time frame: during procedure
Experimental reading task: non-word reading speed
Change from baseline in non-word reading speed during Active tDCS and Active tRNS sessions than during Sham tDCS and Sham tRNS sessions. Non-word reading speed is considered as the syllables/seconds ratio and calculated dividing the total number of syllables pronounced by the total time spent to complete the reading (in seconds).
Time frame: during procedure
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