Brain Stimulation for Dyslexia

Overseen By Tess Fotidzis, PhD

Age: 18 - 65

Sex: Any

Trial Phase: Academic

Sponsor: Vanderbilt University

Must not be taking: Psychotropics, Seizure meds, Stroke meds

Disqualifiers: Intellectual disability, Neurologic pathology, Psychiatric disorders, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 3

225 Participants Needed

Trial Summary

What is the purpose of this trial?

The goal of this project is to address the urgent need for effective, scalable adult literacy interventions by integrating breakthroughs in two separate fields: 1.) the brain network science of resilience to reading disorders and 2.) high-definition non-invasive brain network stimulation. This study will first establish the efficacy of a novel, noninvasive stimulation protocol on reading behavior and brain metrics; then will determine how stimulation-induced effects interact with baseline reading comprehension ability; and lastly, will identify whether stimulation-induced effects are more clinically-beneficial than canonical behavioral interventions. Results may change the foundation for how we treat low adult literacy, and have the potential for wider reaching impacts on non-invasive stimulation protocols for other clinical disorders.

Will I have to stop taking my current medications?

The trial excludes participants who are taking psychotropic medications or medications known to increase the risk of seizures or strokes. If you are on such medications, you may need to stop taking them to participate.

What data supports the effectiveness of this treatment for dyslexia?

Research shows that transcranial direct current stimulation (tDCS), a part of the treatment, has been used to help with motor disabilities and depression by influencing brain activity. This suggests it might also help with dyslexia by potentially improving brain function related to reading and language skills. ^{1 2 3 4 5}

Is brain stimulation for dyslexia safe for humans?

Transcranial electrical stimulation (TES), including transcranial direct current stimulation (tDCS), is generally considered safe in humans, with no serious adverse events reported in over 18,000 sessions. Mild side effects like headaches and skin sensations are common, but serious issues are rare. ^{6 7 8 9 10}

How does the brain stimulation treatment for dyslexia differ from other treatments?

This treatment uses non-invasive brain stimulation, specifically transcranial direct current stimulation (tDCS), to enhance reading abilities by targeting underactive brain areas involved in reading. Unlike other treatments, it shows promise in providing long-lasting improvements in reading skills for individuals with dyslexia, especially when combined with reading training. ^{11 12 13 14 15}

Research Team

Katherine S. Aboud, PhD

Principal Investigator

Vanderbilt University

Eligibility Criteria

This trial is for right-handed, native English-speaking adults aged 18-40 with dyslexia. Participants must not have a low IQ, developmental disorders, visual or hearing impairments that can't be corrected, metal devices in their body, recent migraines, severe fatigue or psychiatric issues. They should not be pregnant and mustn't take certain medications.

Inclusion Criteria

I am right-handed and only speak English.

I am between 18 and 40 years old.

Exclusion Criteria

I have a known neurological condition such as epilepsy or brain injury.

I have been recently diagnosed with migraines.

Hair styles that do not allow for proper EEG net fitting, or that pose potential risks for damage to EEG net

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Baseline Assessment

Establish baseline behavior and brain measures of the individual

1 day

1 visit (in-person, 3.5 hours)

Intervention

Behavioral and non-invasive stimulation intervention, including MRI and EEG sessions

1 day

1 visit (in-person, 3 hours)

Follow-up Assessment

Establish prolonged intervention effects using behavior and brain measures

1 day

1 visit (in-person, 2.5 hours)

Long-term Follow-up

Participants are monitored for changes in reading comprehension and brain activations

12 months

Treatment Details

Interventions

• CCN real non-invasive brain stimulation intervention
• RLN and CCN real non-invasive brain stimulation intervention
• RLN real non-invasive brain stimulation intervention
• Sham intervention

Trial Overview The study tests the effect of non-invasive brain stimulation on reading comprehension in adults with dyslexia. It compares different types of stimulations (RLN and CCN) against a sham intervention to see which improves reading skills and brain function.

Participant Groups

Group I: Reading and Language Network (RLN) Experimental Treatment 1 Intervention

Participants receiving real stimulation to the left angular gyrus and left temporal pole.

Group II: RLN and CCN Experimental Treatment 1 Intervention

Participants receiving real stimulation to the left dorsolateral prefrontal cortex and left angular gyrus.

Group III: Cognitive Control Network (CCN) Experimental Treatment 1 Intervention

Participants receiving real stimulation to the bilateral dorsolateral prefrontal cortices.

Group IV: Sham stimulation Placebo Group 1 Intervention

Participants receiving sham stimulation.

Who Is Running the Clinical Trial?

Vanderbilt University

Lead Sponsor

Trials

714

Recruited

6,143,000+

National Institutes of Health (NIH)

Collaborator

Trials

2,896

Recruited

8,053,000+

Findings from Research

Non-invasive electrical brain stimulation (NEBS), particularly through techniques like transcranial direct current stimulation (tDCS) and transcranial random noise stimulation (tRNS), can effectively modulate brain function and improve motor skills in healthy individuals and patients with motor disabilities.

The article outlines a detailed protocol for applying tDCS to the primary motor cortex, discussing the benefits and drawbacks of different electrode placements, while also addressing safety and tolerability concerns associated with these stimulation methods.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Non-Invasive Electrical Brain Stimulation Montages for Modulation of Human Motor Function. Curado, M., Fritsch, B., Reis, J.[2018]

Transcranial direct current stimulation (tDCS) significantly reduced depression scores in HIV patients co-diagnosed with Major Depressive Disorder (MDD) after a 2-week treatment, indicating its potential as an effective intervention.

The treatment was found to be safe, with no serious adverse events reported, and participants expressed high satisfaction with the protocol, suggesting good acceptability for future studies.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Using Transcranial Direct Current Stimulation to Treat Depression in HIV-Infected Persons: The Outcomes of a Feasibility Study. Knotkova, H., Rosedale, M., Strauss, SM., et al.[2021]

Transcranial current brain stimulation (tCS) techniques, such as tDCS, tACS, and tRNS, use weak electrical currents to influence brain activity noninvasively, with current intensities typically ranging from 0.3 to 5 A/m2.

These methods generate electric fields in the brain that can modulate neuronal activity, and the paper reviews the biophysics behind these interactions, highlighting the need for further research to optimize their therapeutic applications.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Transcranial current brain stimulation (tCS): models and technologies. Ruffini, G., Wendling, F., Merlet, I., et al.[2022]

In a study involving 62 healthy participants, anodal transcranial direct current stimulation (tDCS) at 2 mA for 20 minutes did not show a significant effect on cortical excitability, suggesting that this method may not reliably enhance brain activity as previously thought.

The study also explored individual factors like BDNF genotype and APLM latency to see if they influenced responses to tDCS, but found no evidence of variability in responses among participants, indicating a lack of identifiable 'responders' to the treatment.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

No effect of anodal tDCS on motor cortical excitability and no evidence for responders in a large double-blind placebo-controlled trial. Jonker, ZD., Gaiser, C., Tulen, JHM., et al.[2021]

Transcranial direct current stimulation (tDCS) effectively increases beta-frequency power in the brain, indicating a readiness for improved cognitive functioning, as observed in a study with 10 healthy participants.

This study is significant as it is the first to simultaneously apply tDCS while recording EEG, providing insights into the dynamic changes in brain activity during stimulation.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Beta-frequency EEG activity increased during transcranial direct current stimulation. Song, M., Shin, Y., Yun, K.[2014]

A systematic review of 64 studies involving 2262 participants found that transcranial direct current stimulation (tDCS) has a low dropout rate (6% for active and 7.2% for sham), indicating good acceptability among participants.

Despite the low dropout rates, many studies inadequately reported adverse events (AEs), highlighting a need for improved guidelines to standardize AE reporting in tDCS research.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A Systematic Review on the Acceptability and Tolerability of Transcranial Direct Current Stimulation Treatment in Neuropsychiatry Trials. Aparício, LVM., Guarienti, F., Razza, LB., et al.[2018]

Low intensity transcranial electrical stimulation (TES) is considered safe, with no serious adverse events reported in over 18,000 sessions across various populations, including healthy individuals and patients with neurological or psychiatric conditions.

While moderate adverse events like skin burns from tDCS are rare, mild adverse events such as headaches and fatigue are more common, and the safety profile is consistent across different age groups and vulnerable populations.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Low intensity transcranial electric stimulation: Safety, ethical, legal regulatory and application guidelines. Antal, A., Alekseichuk, I., Bikson, M., et al.[2023]

Microdermabrasion significantly reduced skin resistance by about 32%, allowing for higher doses of transcranial direct current stimulation (tDCS) without increasing skin sensations or device limitations.

The study found that while microdermabrasion increased perceived sensations slightly when not combined with sonication, overall, it enabled safer and more effective delivery of tDCS by lowering the voltage needed to achieve the same current.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Microdermabrasion facilitates direct current stimulation by lowering skin resistance. Chhatbar, PY., Liu, S., Ramakrishnan, V., et al.[2023]

The study assessed the safety of 1.5-mA transcranial direct current stimulation (tDCS) on 49 fasting healthy individuals during Ramadan, finding no serious adverse events or discomfort during the sessions.

There was no significant difference in side effects between active tDCS and sham stimulation, indicating that the tDCS protocol used is safe for fasting adults.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Safety of Transcranial Direct Current Stimulation of Frontal, Parietal, and Cerebellar Regions in Fasting Healthy Adults. Almousa, A., Alajaji, R., Alaboudi, M., et al.[2020]

Transcranial Direct Current Stimulation (tDCS) is generally considered safe, but there are concerns that it could lead to significant negative effects in healthy individuals.

The scientific community needs to be alerted about the potential risks of tDCS, emphasizing the importance of protecting healthy volunteers from possible harm.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Safety of transcranial direct current stimulation in healthy participants. Boccard-Binet, S., Sen, A.[2021]

Eighteen children and adolescents with dyslexia underwent 18 sessions of transcranial direct current stimulation (tDCS) combined with cognitive training, resulting in significant improvements in reading low frequency words and non-words, with effects lasting one month after treatment.

The study found no adverse effects from the tDCS treatment, indicating it is a safe and feasible option for enhancing reading abilities in children and adolescents with dyslexia.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Evidence for reading improvement following tDCS treatment in children and adolescents with Dyslexia. Costanzo, F., Varuzza, C., Rossi, S., et al.[2018]

Transcranial direct current stimulation (tDCS) targeting the left temporo-parietal cortex has shown significant improvements in reading abilities, particularly in individuals with developmental dyslexia (DD), based on a systematic review of nine studies.

tDCS was especially effective for poor readers and those with DD, enhancing skills like word decoding in adults and non-word reading in younger individuals, while not benefiting proficient readers, suggesting its potential as a targeted intervention for reading difficulties.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

tDCS Modulatory Effect on Reading Processes: A Review of Studies on Typical Readers and Individuals With Dyslexia. Cancer, A., Antonietti, A.[2020]

A study involving 26 children and adolescents with dyslexia showed that multiple sessions of transcranial direct current stimulation (tDCS) combined with reading training led to significant and lasting improvements in reading abilities, particularly in non-word and low-frequency word reading efficiency, even 6 months after treatment.

The study found no long-term adverse effects from tDCS, suggesting it is a safe and effective rehabilitative approach for enhancing reading skills in individuals with dyslexia.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Long-lasting improvement following tDCS treatment combined with a training for reading in children and adolescents with dyslexia. Costanzo, F., Rossi, S., Varuzza, C., et al.[2020]

Noninvasive brain stimulation (NIBS) combined with reading training has shown promise in improving reading performance in both children and adults with dyslexia, based on a review of 15 studies.

Targeting classical reading areas with NIBS can enhance various reading-related skills, and there is potential for modulating auditory cortex function to prevent phonological difficulties associated with dyslexia.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The use of noninvasive brain stimulation techniques to improve reading difficulties in dyslexia: A systematic review. Turker, S., Hartwigsen, G.[2023]

In a study involving 19 children and adolescents with dyslexia, transcranial direct current stimulation (tDCS) was found to significantly reduce reading errors during text reading when using a left anodal/right cathodal configuration, indicating a potential therapeutic effect.

The results also showed that the effects of tDCS on reading performance are polarity dependent, suggesting that customizing tDCS parameters could enhance treatment protocols for dyslexia.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Reading changes in children and adolescents with dyslexia after transcranial direct current stimulation. Costanzo, F., Varuzza, C., Rossi, S., et al.[2016]

References

1. United States pubmed.ncbi.nlm.nih.gov

Non-Invasive Electrical Brain Stimulation Montages for Modulation of Human Motor Function. [2018]

2. Switzerland pubmed.ncbi.nlm.nih.gov

Using Transcranial Direct Current Stimulation to Treat Depression in HIV-Infected Persons: The Outcomes of a Feasibility Study. [2021]

3. United States pubmed.ncbi.nlm.nih.gov

Transcranial current brain stimulation (tCS): models and technologies. [2022]

4. United States pubmed.ncbi.nlm.nih.gov

No effect of anodal tDCS on motor cortical excitability and no evidence for responders in a large double-blind placebo-controlled trial. [2021]

5. England pubmed.ncbi.nlm.nih.gov

Beta-frequency EEG activity increased during transcranial direct current stimulation. [2014]

6. United States pubmed.ncbi.nlm.nih.gov

A Systematic Review on the Acceptability and Tolerability of Transcranial Direct Current Stimulation Treatment in Neuropsychiatry Trials. [2018]

7. Netherlands pubmed.ncbi.nlm.nih.gov

Low intensity transcranial electric stimulation: Safety, ethical, legal regulatory and application guidelines. [2023]

8. England pubmed.ncbi.nlm.nih.gov

Microdermabrasion facilitates direct current stimulation by lowering skin resistance. [2023]

9. Switzerland pubmed.ncbi.nlm.nih.gov

Safety of Transcranial Direct Current Stimulation of Frontal, Parietal, and Cerebellar Regions in Fasting Healthy Adults. [2020]

10. United States pubmed.ncbi.nlm.nih.gov

Safety of transcranial direct current stimulation in healthy participants. [2021]

11. Netherlands pubmed.ncbi.nlm.nih.gov

Evidence for reading improvement following tDCS treatment in children and adolescents with Dyslexia. [2018]

12. Switzerland pubmed.ncbi.nlm.nih.gov

tDCS Modulatory Effect on Reading Processes: A Review of Studies on Typical Readers and Individuals With Dyslexia. [2020]

13. England pubmed.ncbi.nlm.nih.gov

Long-lasting improvement following tDCS treatment combined with a training for reading in children and adolescents with dyslexia. [2020]

14. United States pubmed.ncbi.nlm.nih.gov

The use of noninvasive brain stimulation techniques to improve reading difficulties in dyslexia: A systematic review. [2023]

15. England pubmed.ncbi.nlm.nih.gov

Reading changes in children and adolescents with dyslexia after transcranial direct current stimulation. [2016]