Stochastic Resonance Applied to Amblyopia Training and the Plasticity of Brain

Study Overview
=================
Brief Summary
-----------------
The prevalence of Taiwan's population with amblyopia is 2-5%. Amblyopia affects the daily life and learning ability. The human visual system can be developed normally with exposure of clear images on the retina, which often drive the development and projection of optic nerves progressively. In general, the visual acuity progresses gradually with age. A normal vision is relatively mature until 8 years old. Several types of amblyopia (strabismic amblyopia, refractive amblyopia, and deprivation amblyopia) are identified. The refractive amblyopia and deprivation amblyopia must be corrected by wearing glasses or surgeries. Otherwise, amblyopia is often corrected by occlusion of the dominant eye or amblyopia training. The Cambridge Stimulator (CAM) with rotating grating is commonly used in clinic in Taiwan. The principle of the CAM allows subjects to draw pictures on the plate in coincidence with occlusion of the dominant eye. The parents have to go with their children to a hospital weekly. The CAM training is a stereotyped visuomotor behavior, which usually causes fatigue and uninteresting results for children. Recently, some computer games have been incorporated with CAM training. However, their clinical impact on amblyopia is largely unknown. Moreover, most of studies don't have long-term tracking, and they only use limited assessments. In this project, a home-based training would be built for children with amblyopia. A CAM training with a hierarchical structure with story-based organization would be implemented in the tablet. It will save time for children and parents for traffic between the home and hospital. The CAM training with organized structure would increase acceptability and create subjects' motivation for long-term training. In addition, a stochastic resonance theory would be incorporated with the CAM training to potentiate the learning curve of a visuomotor skill in young children. Five systematic assessments, including visual acuity, grating acuity, contrast sensitivity, and 2 measurements of visual evoked potentials (VEPs), would be used. The investigators hypothesized that the rotating grating stimulation and stochastic resonance stimulation groups showed significant enhancement of the visual functions compared with the control group and performance of the VEPs toward better eye through the home-based training apparatus.

Official Title
-----------------
Stochastic Resonance Applied to Amblyopia Training and the Plasticity of Brain

Conditions
-----------------
Amblyopia, Amblyopia, Anisometropic

Intervention / Treatment
-----------------
* Device: Portable tablet


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Participants were 4-8 years old. Participant had binocular or monocular best-corrected visual acuity (BCVA) of ≤0.8, or they exhibited binocular BCVA difference of ≥0.2. Participant had the wearing of optimal spectacle correction. Exclusion Criteria: Children with deprivation amblyopia were excluded. Children with ptosis were excluded.

Ages Eligible for Study
-----------------
Minimum Age: 4 Years
Maximum Age: 8 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Control group<br>This group received eye-hand practice for drawing pictures. | Device: Portable tablet<br>* Each training session was limited to 15 minutes a day, 5 days a week. The entire training period was 6 months.<br>|
| Experimental: Grating group<br>This group received eye-hand practice for drawing pictures with rotating grating stimuli of various spatial frequencies. | Device: Portable tablet<br>* Each training session was limited to 15 minutes a day, 5 days a week. The entire training period was 6 months.<br>|
| Experimental: Random dot group<br>This group received eye-hand practice for drawing pictures with rotating grating stimuli of various spatial frequencies constructed by random dots of stochastic resonance. | Device: Portable tablet<br>* Each training session was limited to 15 minutes a day, 5 days a week. The entire training period was 6 months.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Visual acuity (VA) | Landolt C chart was used. | Change from Baseline VA at 1, 2, 3 and 6 months | 
| Grating acuity (GA) | Horizontal or vertical square-wave grating stimuli were used. | Change from Baseline GA at 1, 2, 3 and 6 months | 
| Contrast sensitivity (CS) | Circular-shape horizontal square-wave grating stimuli were used. | Change from Baseline CS at 1, 2, 3 and 6 months | 
| Visual evoked potential (VEP) | Transient VEP and Steady state VEP of the Cortical EEG were recorded. | Change from Baseline VEP at 1, 2, 3 and 6 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Total practice duration | Practice duration was recorded in the tablet. | Throughout 6 months | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Amblyopia, Amblyopic training, Contrast sensitivity, Grating acuity, Stochastic resonance, Visual acuity, Visual evoked potential