Developmental Dyslexia
Conditions
Keywords
Developmental Dyslexia, tDCS, Phonological Awareness, Fine Motor Training, Reading, Children, Dual-site transcranial direct current stimulation
Brief summary
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.
Detailed description
This is a randomized, double-blind, sham-controlled, 8-group component trial in 9-year-old boys with developmental dyslexia. The study tests a theory-driven prediction derived from multiple-deficit models of dyslexia: that simultaneously targeting reading-related and sensory-motor brain networks, while delivering an integrated phonological and fine motor intervention, produces greater and more durable reading improvement than single-component interventions. The tDCS protocol uses 1 mA current for 20 minutes per session over 20 sessions (3 sessions/week). Electrode montages are yoked to the type of cognitive intervention: left temporoparietal (TPJ) for phonological training, left primary motor cortex (M1) for motor training, and dual-site TPJ+M1 for the combined intervention. A tDCS-only group (M1 montage) is included to isolate the effect of motor cortex stimulation. Primary outcome: change in the composite score of Factor 1 of the Reading and Dyslexia Test (word reading, phoneme deletion, nonword reading, and word comprehension). Secondary outcomes: fine motor performance (BOT-2), rapid automatized naming, and text reading fluency. Assessments occur at baseline, immediately after the intervention, and at 3- and 6-month follow-ups.
Interventions
DEVICEActive transcranial direct current stimulation (tDCS)
Active tDCS will be delivered at 1 milliampere for 20 minutes per session, 20 sessions over about 7 weeks. The montage varies by arm: left temporoparietal (TPJ) montage, left primary motor cortex (M1) montage, or dual-site TPJ+M1 montage.
DEVICESham transcranial direct current stimulation (tDCS)
Sham tDCS will use the same electrode positions as the active groups, but the current will be applied for only 30 seconds and then gradually ramped down.
BEHAVIORALPhonological awareness training
20 sessions of 60 minutes each, three times per week for about 7 weeks. Covers syllable segmentation, rhyme, phoneme blending and segmentation, initial and final phoneme identification, phoneme manipulation, and grapheme-to-phoneme mapping.
BEHAVIORALNon-targeted fine motor training
20 sessions of 60 minutes each, three times per week for about 7 weeks. Includes activities without linguistic content, such as free play with dough, bead threading, pegboard tasks, and other manual dexterity exercises.
BEHAVIORALIntegrated phonological and fine motor intervention
20 sessions of 60 minutes each, three times per week for about 7 weeks. Combines phonological awareness training with targeted fine motor activities linked to reading, such as forming letters with dough and stringing beads marked with phonemes.
OTHERUsual school education
Participants receive the standard school curriculum without additional cognitive or motor training.
Sponsors
Shahid Beheshti University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Masking description
Cognitive therapists are also blinded. The tDCS operator is the only unblinded person and has no role in cognitive training or outcome assessment. Data analysts are blinded until the primary analyses are completed. The Data Safety and Monitoring Board may be unblinded as needed for safety monitoring.
Intervention model description
Eight-arm component design. The tDCS montage is yoked to the type of cognitive intervention (TPJ for phonological training, M1 for motor training, dual-site TPJ+M1 for the combined intervention). Not all possible montage × training combinations are evaluated; therefore, this is not a complete factorial design.
Eligibility
Sex/Gender
MALE
Age
108 Months to 119 Months
Healthy volunteers
No
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).
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Composite score of Factor 1 of the Reading and Dyslexia Test (NAMA) | Before intervention, immediately after the end of intervention, 3 months after intervention, and 6 months after intervention. | Composite score of Factor 1 of the Reading and Dyslexia Test, which includes word reading, phoneme deletion, nonword reading, and word comprehension subtests. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Fine motor performance (BOT-2 manual dexterity and upper-limb coordination) | Before intervention, immediately after the end of intervention, 3 months after intervention, and 6 months after intervention. | Fine motor performance as measured by the Bruininks-Oseretsky Test of Motor Proficiency, Second Edition, manual dexterity and upper-limb coordination subtests. Raw scores of the common items will be used for longitudinal comparison. |
| Rapid automatized naming speed | Before intervention, immediately after the end of intervention, 3 months after intervention, and 6 months after intervention. | Rapid automatized naming speed, including naming of objects, colors, numbers, and letters. The total time in seconds to name each card is recorded. |
| Text reading fluency (correct words per minute) | Before intervention, immediately after the end of intervention, 3 months after intervention, and 6 months after intervention. | Text reading fluency defined as the number of correct words read per minute on a grade-level reading passage. Correct words per minute will be calculated as the total number of words minus errors, multiplied by 60, divided by the total reading time in seconds. |
Countries
Iran
Contacts
CONTACTMohammad Amin Javedanfar, MSc
STUDY_CHAIRShahriar Gharibzadeh, Ph.D.
Institute for Cognitive and Brain Sciences, Shahid Beheshti University
Outcome results
None listed