Improving Vision in Adults With Macular Degeneration, Study 1: the Effect of Brain Stimulation
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 21
- 试验地点
- 3
- 主要终点
- Rapid Serial Visual Presentation (RSVP) Reading Pre-Test
研究概览
简要总结
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.
详细描述
This study will be carried out in Ontario, Canada (University of Waterloo) and Hong Kong (The Hong Kong Polytechnic University). There are two conditions: Active brain stimulation and sham/placebo brain stimulation. This study uses a within-subjects design, such that all participants will take part in both conditions on separate sessions.
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.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Treatment
- 盲法
- Double (Participant, Investigator)
盲法说明
The participant and the researcher will be blind to the order of the sessions for each participant.
入排标准
- 年龄范围
- 18 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •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).
排除标准
- •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
结局指标
主要结局
Rapid Serial Visual Presentation (RSVP) Reading Pre-Test
时间窗: This test is roughly 6 minutes in length, occurring before brain 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.
Rapid Serial Visual Presentation (RSVP) Reading Post-Test 1 (during stimulation)
时间窗: This test is roughly 6 minutes in length, occurring during the 20 minute brain stimulation period.
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.
Rapid Serial Visual Presentation (RSVP) Reading Post-Test 2 (5 min after stimulation)
时间窗: This test is roughly 6 minutes in length, occurring 5 minutes after the completion of 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.
Rapid Serial Visual Presentation (RSVP) Reading Post-Test 3 (30 min after stimulation)
时间窗: This test is roughly 6 minutes in length, occurring 30 minutes after the completion of 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.
次要结局
- Crowded 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.)
- 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.)
- Crowded 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.)
- Crowded 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.)
研究者
Ben Thompson
Professor; Associate Director for Research
University of Waterloo