Brain Stimulation With Combined Reading and Motor Training for Children With Dyslexia

Effectiveness of Dual-Site tDCS Combined With Integrated Phonological and Fine Motor Intervention in 9-Year-Old Boys With Developmental Dyslexia: A Randomized, Double-Blind, Sham-Controlled Trial

This study examines whether combining non-invasive brain stimulation (tDCS) with an integrated reading-and-motor training program improves reading and phonological processing in 9-year-old boys with developmental dyslexia.

Children with dyslexia often have difficulties in phonological awareness and fine motor skills. This study targets two brain areas at the same time: the left temporoparietal junction (important for reading and phonological processing) and the left primary motor cortex (important for hand movements and speech-related motor processes).

Participants will be randomly assigned to one of eight groups. Some groups will receive active brain stimulation, and some will receive sham (inactive) stimulation, while also participating in different types of training: phonological awareness training, fine motor training, combined phonological and fine motor training, or no training. The treatment includes 20 sessions, three times per week for about 7 weeks.

Reading and phonological skills will be measured before treatment, immediately after treatment, and again 3 months and 6 months later. The study will help determine whether a full treatment package-using brain stimulation together with combined reading and motor training-is more effective than single treatments or usual school education.

Inclusion Criteria:

• Male children aged 9 years (9 years 0 months to 9 years 11 months) with developmental dyslexia diagnosed according to DSM-5 criteria by a clinical team.
• Reading and Dyslexia Test (NAMA) T score ≤ 30 (at least 2 standard deviations below the mean).
• Full Scale IQ ≥ 85 on the Wechsler Intelligence Scale for Children, Fifth Edition (WISC-V).
• Score below 88 on the Spence Children's Anxiety Scale (SCAS).
• Fine motor deficits defined as standard score ≤ 40 on Bruininks-Oseretsky Test of Motor Proficiency, Second Edition (BOT-2) manual dexterity and upper-limb coordination subtests.
• Normal or corrected-to-normal vision and hearing.
• No history of seizure or epilepsy, no scalp skin disease, no cochlear implant, cardiac pacemaker, or metal implants in the skull.
• Written informed consent from parents or legal guardian and verbal assent from the child.

Exclusion Criteria:

• Intellectual disability (Full Scale IQ < 85).
• Personal history of epilepsy or seizure disorder, or epilepsy in a first-degree relative.
• Presence of cochlear implant, cardiac pacemaker, or metal implants in the skull.
• Skin diseases or open lesions on the scalp at electrode sites.
• Uncorrected visual or hearing impairments.
• Other primary psychiatric or neurodevelopmental disorders requiring ongoing treatment (e.g., ADHD, autism spectrum disorder, severe anxiety disorder).