Study Results
The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.
Basic Information
Get a concise snapshot of the trial, including recruitment status, study phase, enrollment targets, and key timeline milestones.
COMPLETED
NA
21 participants
INTERVENTIONAL
2019-12-01
2022-03-01
Brief Summary
Review the sponsor-provided synopsis that highlights what the study is about and why it is being conducted.
Related Clinical Trials
Explore similar clinical trials based on study characteristics and research focus.
Clinical Treatment of Transcranial Direct Current Stimulation in Older Adolescents With Amblyopia
NCT06760910
Brain Stimulation Effects on Orientation and Mobility Skills in Adults With Vision Impairment
NCT07341763
Visual Cortex Stimulation in Patients With Amblyopia
NCT00097162
Anodal tDCS With Compensatory Audio-visual Training for Acquired Visual Field Defects After Brain Injury
NCT06116760
Oculomotor Training and Chinese Characters Recognition in Children With Neuromuscular Disease
NCT03627962
Detailed Description
Dive into the extended narrative that explains the scientific background, objectives, and procedures in greater depth.
Participants will be recruited from university-affiliated clinics and local clinical practices. Following full informed consent, participants will complete baseline testing and clinical testing to confirm that they meet eligibility criteria including: a diagnosis of macular degeneration without any additional eye disease, impaired vision but with enough visual acuity that the computer monitor can still present readable word, and no contraindications for brain stimulation interventions. Eligible participants will then be randomized to either receiving the active stimulation first or the placebo stimulation first.
The primary outcome measure is verbal reading accuracy for sentences presented on a computer screen following a Rapid Serial Visual Presentation (RSVP) task in which a single word is presented on the screen at a time. Participants will freely observe the words and will indicate the words on the screen verbally. The secondary outcome measures are crowded and uncrowded visual acuity as measured by Freiburg Visual Acuity \& Contrast Test (FrACT) using the Landolt C stimulus. The "C"'s gap will be oriented randomly, and the participant will indicate the orientation of the stimulus. Crowded visual acuity will be assessed with Landolt C surrounded by a solid ring, while uncrowded visual acuity will be assessed with the Landolt C alone.
The study consists of 3 sessions:
Session 1: The first session will include the clinical evaluation. In addition, the first session will also collect the participant's individual RSVP performance threshold by presenting a variety of reading speeds and print sizes. The selected threshold will be the combination of print size and presentation speed required for a given participant to achieve roughly 55% performance accuracy.
Session 2 and 3: Brain stimulation sessions. At the start of each session, participants will perform baseline pre tests for the uncrowded and crowded visual acuity tasks as well as the RSVP task using their selected threshold from Session 1. They will then undergo a-tDCS to their primary visual cortex - this stimulation may be either active or placebo on any given day, but all participants will have been exposed to both sham and placebo by the end of Session 3. During the brain stimulation, participants will perform post tests for the primary outcome measure (RSVP) and the two secondary outcome measures (crowded and uncrowded visual acuity). Five minutes after the completion of the brain stimulation, participants will again perform all three post tests. A third set of post tests will be completed 30 minutes after the completion of the brain stimulation.
All outcome measures will be analyzed by comparing the baseline (pre test) scores to the post test scores, examining whether the active brain stimulation condition resulted in greater post test improvement relative to the placebo brain stimulation condition. The time course of the effect of brain stimulation will also be examined by comparing the effect of brain stimulation at each of the 3 post tests to one another.
Conditions
See the medical conditions and disease areas that this research is targeting or investigating.
Study Design
Understand how the trial is structured, including allocation methods, masking strategies, primary purpose, and other design elements.
RANDOMIZED
CROSSOVER
TREATMENT
DOUBLE
Study Groups
Review each arm or cohort in the study, along with the interventions and objectives associated with them.
Active then Sham
Participants in this arm will be exposed to active stimulation during session 1 and sham/placebo stimulation during session 2
anodal tDCS Active Stimulation
a weak electric current is applied to the head through electrodes to affect the cortical excitability of the targeted cells in the brain.
anodal tDCS Sham/Placebo Stimulation
The tDCS machine will be used as in active stimulation, except the electrical current will not be applied.
Sham then Active
Participants in this arm will be exposed to sham/placebo stimulation during session 1 and active stimulation during session 2
anodal tDCS Active Stimulation
a weak electric current is applied to the head through electrodes to affect the cortical excitability of the targeted cells in the brain.
anodal tDCS Sham/Placebo Stimulation
The tDCS machine will be used as in active stimulation, except the electrical current will not be applied.
Interventions
Learn about the drugs, procedures, or behavioral strategies being tested and how they are applied within this trial.
anodal tDCS Active Stimulation
a weak electric current is applied to the head through electrodes to affect the cortical excitability of the targeted cells in the brain.
anodal tDCS Sham/Placebo Stimulation
The tDCS machine will be used as in active stimulation, except the electrical current will not be applied.
Eligibility Criteria
Check the participation requirements, including inclusion and exclusion rules, age limits, and whether healthy volunteers are accepted.
Inclusion Criteria
2. Central vision loss and use of a peripheral preferred retinal locus (PRL) to fixate on visual objects, as confirmed by a microperimeter.
3. Visual acuity (VA); between 0.5 and 1.0 logMAR inclusive (6/18-6/60) in the better eye.
4. Best-corrected near visual acuity of 4.0M at 40 cm or better in the better eye
5. Stable vision for the previous 3 months (by patient report).
Exclusion Criteria
2. Not fluent in reading English (Waterloo) or Chinese characters (Hong Kong).
3. Any ocular surgery (including anti-vegF injections) within the duration of the study.
4. Ocular pathology other than JMD or AMD that can reduce central vision.
5. Severe hearing impairment.
6. Contraindications for brain stimulation
18 Years
ALL
No
Sponsors
Meet the organizations funding or collaborating on the study and learn about their roles.
The Hong Kong Polytechnic University
OTHER
University of Waterloo
OTHER
Responsible Party
Identify the individual or organization who holds primary responsibility for the study information submitted to regulators.
Ben Thompson
Professor; Associate Director for Research
Principal Investigators
Learn about the lead researchers overseeing the trial and their institutional affiliations.
Ben Thompson, PhD
Role: PRINCIPAL_INVESTIGATOR
University of Waterloo
Locations
Explore where the study is taking place and check the recruitment status at each participating site.
University of Waterloo
Waterloo, Ontario, Canada
The Hong Kong Polytechnic University
Hung Hom, Kowloon, Hong Kong
Countries
Review the countries where the study has at least one active or historical site.
Provided Documents
Download supplemental materials such as informed consent forms, study protocols, or participant manuals.
Document Type: Study Protocol
Document Type: Statistical Analysis Plan
Other Identifiers
Review additional registry numbers or institutional identifiers associated with this trial.
VSBrainStim1
Identifier Type: -
Identifier Source: org_study_id
More Related Trials
Additional clinical trials that may be relevant based on similarity analysis.