Stochastic Resonance Applied to Amblyopia Training and the Plasticity of Brain

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.

Study Overview

• Status: Completed
• Conditions: Amblyopia; Amblyopia, Anisometropic
• Intervention / Treatment: Device: Portable tablet

• Study Type: Interventional
• Enrollment (Actual): 51
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 4 years to 8 years (CHILD)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

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 Plan

How is the study designed?

Design Details

• Primary Purpose: TREATMENT
• Allocation: RANDOMIZED
• Interventional Model: PARALLEL
• Masking: TRIPLE

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
ACTIVE_COMPARATOR: Control group; This group received eye-hand practice for drawing pictures.	Device: Portable tablet; Each training session was limited to 15 minutes a day, 5 days a week. The entire training period was 6 months.
EXPERIMENTAL: Grating group; This group received eye-hand practice for drawing pictures with rotating grating stimuli of various spatial frequencies.	Device: Portable tablet; Each training session was limited to 15 minutes a day, 5 days a week. The entire training period was 6 months.
EXPERIMENTAL: Random dot group; 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; Each training session was limited to 15 minutes a day, 5 days a week. The entire training period was 6 months.

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

Collaborators and Investigators

• Sponsor: National Cheng-Kung University Hospital
• Collaborators: Chang Gung Memorial Hospital
• Investigators: Principal Investigator: Fu-Zen Shaw, Professor, Department of Pyschology, National Cheng Kung University

Publications and helpful links

General Publications

• Yeh WH, Lai LJ, Chang DW, Lin WS, Lin GM, Shaw FZ. Portable rotating grating stimulation for anisometropic amblyopia with 6 months training. Sci Rep. 2021 Jun 1;11(1):11430. doi: 10.1038/s41598-021-90936-7.

Study record dates

Study Major Dates

• Study Start (ACTUAL): July 15, 2013
• Primary Completion (ACTUAL): January 31, 2016
• Study Completion (ACTUAL): January 31, 2016

Study Registration Dates

• First Submitted: December 22, 2019
• First Submitted That Met QC Criteria: December 24, 2019
• First Posted (ACTUAL): December 30, 2019

Study Record Updates

• Last Update Posted (ACTUAL): December 30, 2019
• Last Update Submitted That Met QC Criteria: December 24, 2019
• Last Verified: December 1, 2019

More Information

Terms related to this study

• Keywords: Amblyopia; Visual acuity; Contrast sensitivity; Amblyopic training; Grating acuity; Stochastic resonance; Visual evoked potential
• Additional Relevant MeSH Terms: Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Eye Diseases; Neurologic Manifestations; Sensation Disorders; Vision Disorders; Amblyopia
• Other Study ID Numbers: A-BR-102-050-t

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No