Impact of Transcranial Direct Current Stimulation on Reading Skills of Children and Adolescents With Dyslexia

Abstract

Introduction:Rehabilitation techniques have been used to facilitate reading acquisition in dyslexia. However, many individuals continue to present academic impairment throughout life. New intervention strategies are necessary to further help this population.Objectives:Assess the impact of transcranial direct current stimulation on reading skills in children and adolescents with dyslexia.Methods:The study was conducted with one-group pretest–posttest. Participants received 2 mA transcranial direct current stimulation during 30 minutes for 5 consecutive days. Reading performance was measured by a group of tasks (identification and reading of letters, syllables, words, nonwords, and text).Results:A significant increase in the number of correct answers for nonwords and text tasks was observed after transcranial direct current stimulation (P = .035 and P = .012, respectively).Conclusion:The transcranial direct current stimulation seems to be a promising tool for the treatment of reading problems in dyslexia. Future studies are necessary to confirm the effects of transcranial direct current stimulation and to establish optimal intervention protocol in this population.

Beyond Reading Modulation: Temporo-Parietal tDCS Alters Visuo-Spatial Attention and Motion Perception in Dyslexia

“…The possibility to modulate reading in individuals with and without dyslexia using transcranial electrical stimulation, such as tDCS, has been documented in the literature [ 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 ]. Nevertheless, the underlying neurocognitive mechanisms mediating reading changes induced by tDCS are still not well understood.…”

“…A number of studies have demonstrated the positive effect of tDCS on reading [ 54 , 55 , 56 ] and, particularly, in dyslexia [ 57 , 58 , 59 , 60 , 61 , 62 ]. In typically reading adults, an overall improvement in word reading efficiency has been observed after the application of left anodal/right cathodal tDCS over the temporo-parietal areas [ 54 ] as well as following left anodal stimulation over the inferior parietal lobule [ 55 , 56 ].…”

“…In children with dyslexia, a substantial effect on word reading fluency [ 62 ], low-frequency word reading accuracy, and nonword reading fluency [ 59 , 60 ] was found after six weeks of left anodal/right cathodal tDCS over the temporo-parietal regions. Similarly, a beneficial effect on text and nonword reading accuracy was shown following five sessions of left anodal tDCS over the mid-posterior temporal area in children and adolescents with dyslexia [ 61 ].…”

The effects of transcranial direct current stimulation on attention and inhibitory control of children and adolescents with attention-deficit/hyperactivity disorder (ADHD)

“…[ 24 ] The anodic tDCS is based on an electric current from a generator that aims to stimulate certain cortical areas, causing an increase in local cerebral blood flow. [ 25 ] This tool has been currently used in the treatment of various psychiatric and neurological disorders such as schizophrenia, [ 26 ] dyslexia, [ 27 ] autism, [ 28 ] cerebellar ataxia, [ 29 ] epilepsy, [ 30 ] unipolar and bipolar depression, [ 31 ] since it is considered safe and relatively less expensive than other noninvasive brain stimulation approaches. [ 32 , 33 ] Advantages of the cost-effectiveness of tDCS could be even more important considering low-middle income countries.…”

Effective spelling training is not enhanced by tDCS in adults

“…In 2018, Cancer and Antonietti (2018) published a review of studies that examined the effect of tDCS on reading or spelling outcomes (see Appendix A for a summary of relevant studies). These studies can be categorised according to whether they administered (1) single tDCS stimulation before or during a reading or spelling assessment (Before: Boehringer, Macher, Dukart, Villringer, & Pleger, 2013;Costanzo, Varuzza, Rossi, Sdoia, Varvara, Oliveri, Koch, et al, 2016a;Cummine et al, 2019;Heth & Lavidor, 2015;Rios et al, 2018;Turkeltaub et al, 2012;Younger, Randazzo Wagner, & Booth, 2016;During: Thomson et al, 2015;Westwood et al, 2017); or (2) repeated stimulation during reading or spelling training (Costanzo et al, 2016b(Costanzo et al, , 2018. Most of these studies administered anodal stimulation over left-hemisphere regions which are thought to be associated with reading ability (e.g., temporo-parietal cortex, posterior temporal lobe, inferior frontal gyrus, occipital visual cortex), with cathodal or reference electrodes position over the right hemisphere (i.e., temporo-parietal cortex, orbitofrontal cortex) or on the right cheek.…”