Improving Vision in Adults With Macular Degeneration

NCT04111068 | Completed

• 1 other identifier: VSBrainStim1
• Study Type: interventional
• Target: 21
• Locations: 2 countries
• Sites: 2

Brief Summary

The purpose of this study is to test whether a kind of brain stimulation called anodal transcranial direct current stimulation (a-tDCS) can improve the ability of people with age-related macular degeneration (AMD) or juvenile macular degeneration (JMD) to read words presented to them on a computer screen. In addition, secondary measures of visual acuity will also be examined to determine whether brain stimulation can allow patients to resolve finer details of an image. The proposed treatment is the application of a-tDCS onto the participant's head, with brain stimulation aimed at Primary Visual Cortex toward the occipital pole. The investigators will test the ability of participants to read words before and after the application of stimulation. The difference between the pre and post tests when receiving active stimulation will be compared to the difference when receiving sham stimulation, because sham stimulation is not expected to improve reading beyond a placebo. The aim of the study is to examine the potential of brain stimulation as an effective treatment for macular degeneration that may be used in conjunction with more traditional eye-based interventions. The investigators hypothesize that the brain stimulation will enable higher performance in the reading task and secondary measures due to an increase in the cortical excitability of the stimulated brain cells.

Conditions

Macular Degeneration

Keywords

Macular Degeneration; Brain Stimulation; Psychophysics; Reading; tDCS; RSVP; Visual Acuity; Uncrowded Visual Acuity; Crowded Visual Acuity

Outcome Measures

Primary Outcomes (4)

• Rapid Serial Visual Presentation (RSVP) Reading Pre-Test

  Behavioral Measure - Participants will verbally read words presented on a computer. The speed of the presentation and the size of the words will be personalized to the participant so that roughly 50% accuracy can be expected.

  This test is roughly 6 minutes in length, occurring before brain stimulation.

• Rapid Serial Visual Presentation (RSVP) Reading Post-Test 1 (during stimulation)

  Behavioral Measure - Participants will verbally read words presented on a computer. The speed of the presentation and the size of the words will be personalized to the participant so that roughly 50% accuracy can be expected without accounting for any effects of stimulation.

  This test is roughly 6 minutes in length, occurring during the 20 minute brain stimulation period.

• Rapid Serial Visual Presentation (RSVP) Reading Post-Test 2 (5 min after stimulation)

  Behavioral Measure - Participants will verbally read words presented on a computer. The speed of the presentation and the size of the words will be personalized to the participant so that roughly 50% accuracy can be expected without accounting for any effects of stimulation.

  This test is roughly 6 minutes in length, occurring 5 minutes after the completion of stimulation.

• Rapid Serial Visual Presentation (RSVP) Reading Post-Test 3 (30 min after stimulation)

  Behavioral Measure - Participants will verbally read words presented on a computer. The speed of the presentation and the size of the words will be personalized to the participant so that roughly 50% accuracy can be expected without accounting for any effects of stimulation.

  This test is roughly 6 minutes in length, occurring 30 minutes after the completion of stimulation.

Secondary Outcomes (8)

• Uncrowded Visual Acuity Pre-Test

  Roughly 2 minutes in length, administered after the primary outcome measure "RSVP Reading Pre-Test" before brain stimulation.

• Uncrowded Visual Acuity Post-Test 1 (during stimulation)

  Roughly 2 minutes in length, administered after the primary outcome measure "RSVP Reading Post-Test 1" while brain stimulation is ongoing.

• Uncrowded Visual Acuity Post-Test 2 (5 min after Stimulation)

  Roughly 2 minutes in length, administered after the primary outcome measure "RSVP Reading Post-Test 2" 5 minutes after brain stimulation completion.

• Uncrowded Visual Acuity Post-Test 3 (30 min after Stimulation)

  Roughly 2 minutes in length, administered after the primary outcome measure "RSVP Reading Post-Test 3" 30 minutes after brain stimulation completion.

• Crowded Visual Acuity Pre-Test

  Roughly 2 minutes in length, administered after the primary outcome measure "RSVP Reading Pre-Test" before brain stimulation.

Study Arms (2)

Active then Sham

EXPERIMENTAL

Participants in this arm will be exposed to active stimulation during session 1 and sham/placebo stimulation during session 2

Device: anodal tDCS Active Stimulation; Device: anodal tDCS Sham/Placebo Stimulation

Sham then Active

EXPERIMENTAL

Participants in this arm will be exposed to sham/placebo stimulation during session 1 and active stimulation during session 2

Device: anodal tDCS Active Stimulation; Device: anodal tDCS Sham/Placebo Stimulation

Interventions

anodal tDCS Active Stimulation DEVICE

a weak electric current is applied to the head through electrodes to affect the cortical excitability of the targeted cells in the brain.

Active then Sham; Sham then Active

anodal tDCS Sham/Placebo Stimulation DEVICE

The tDCS machine will be used as in active stimulation, except the electrical current will not be applied.

Active then Sham; Sham then Active

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Diagnosis of AMD (age 60+) or JMD (current age 18+).
• Central vision loss and use of a peripheral preferred retinal locus (PRL) to fixate on visual objects, as confirmed by a microperimeter.
• Visual acuity (VA); between 0.5 and 1.0 logMAR inclusive (6/18-6/60) in the better eye.
• Best-corrected near visual acuity of 4.0M at 40 cm or better in the better eye
• Stable vision for the previous 3 months (by patient report).

You may not qualify if:

• Diagnosed dementia.
• Not fluent in reading English (Waterloo) or Chinese characters (Hong Kong).
• Any ocular surgery (including anti-vegF injections) within the duration of the study.
• Ocular pathology other than JMD or AMD that can reduce central vision.
• Severe hearing impairment.
• Contraindications for brain stimulation

Sponsors & Collaborators

• University of Waterloo: lead
• The Hong Kong Polytechnic University: collaborator

Study Sites (2)

University of Waterloo

Waterloo, Ontario, N2L 3G1, Canada

Location

The Hong Kong Polytechnic University

Hung Hom, Kowloon, Hong Kong

Location

MeSH Terms

Conditions

Macular Degeneration

Condition Hierarchy (Ancestors)

Retinal Degeneration; Retinal Diseases; Eye Diseases

Study Officials

• Ben Thompson, PhD

  University of Waterloo

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Masking Details: The participant and the researcher will be blind to the order of the sessions for each participant.
• Purpose: TREATMENT
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor; Associate Director for Research

Model Details: 1 session of active brain stimulation and 1 session of placebo sham stimulation. Each participant will perform both sessions in a randomly-assigned order.

Study Record Dates

• First Submitted: September 23, 2019
• First Posted: October 1, 2019
• Study Start: December 1, 2019
• Primary Completion: March 1, 2022
• Study Completion: March 1, 2022
• Last Updated: April 29, 2022

Record last verified: 2022-04

Data Sharing

• IPD Sharing: Will share
• Shared Documents: ANALYTIC CODE
• Time Frame: IDP will be available upon a publication, and no more than 9 months after the publication.
• Access Criteria: IDP will be shared to researchers who provide a methodologically sound proposal.

Locations

CA (1); HK (1)