Stochastic Resonance Applied to Amblyopia Training and the Plasticity of Brain

Not Applicable

Completed

• Conditions: Amblyopia; Amblyopia, Anisometropic
• Interventions: Device: Portable tablet

• Registration Number: NCT04213066
• Lead Sponsor: National Cheng-Kung University Hospital

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.

Detailed Description

Not available

Study Timeline

• Study Start: 2013-07-15
• Primary Completion: 2016-01-31
• Study Completion: 2016-01-31
• Status Verified: 2019-12
• Study First Submitted: 2019-12-22
• Study First Submitted QC: 2019-12-24
• Last Update Submitted: 2019-12-24
• Study First Posted: 2019-12-30
• Last Update Posted: 2019-12-30

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 51

Inclusion Criteria

1. Participants were 4-8 years old.
2. Participant had binocular or monocular best-corrected visual acuity (BCVA) of ≤0.8, or they exhibited binocular BCVA difference of ≥0.2.
3. Participant had the wearing of optimal spectacle correction.

Exclusion Criteria

1. Children with deprivation amblyopia were excluded.
2. Children with ptosis were excluded.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Control group	Portable tablet	This group received eye-hand practice for drawing pictures.
Grating group	Portable tablet	This group received eye-hand practice for drawing pictures with rotating grating stimuli of various spatial frequencies.
Random dot group	Portable tablet	This group received eye-hand practice for drawing pictures with rotating grating stimuli of various spatial frequencies constructed by random dots of stochastic resonance.

Primary Outcome Measures

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

Secondary Outcome Measures

Name	Time	Method
Total practice duration	Throughout 6 months	Practice duration was recorded in the tablet.