Testing Tactile Aids With Blind Subjects

University of Delaware

Status: Enrolling

Conditions: Vision, Low; Blindness

Treatments: Behavioral: Improving signal from a single bump with designer materials; Behavioral: Single bump acuity; Behavioral: Optimal spacing between bumps

Study type: Interventional

Funder types: Other

Identifiers

NCT06237829

372362

Details and patient eligibility

About

The objective of this project is to create richer tactile aids by using materials chemistry to create tactile sensations in tactile aids, as an alternative to traditional physical bumps, lines, or textures. These materials are commonly used in household products, but have not yet been used to enrich tactile aids. Successful outcomes are primarily the accuracy with which low vision or blind subjects identify objects made from tactile coatings versus traditional tactile aids. Other outcomes include time to completion of the task, or the number of distinctive categories that participants can identify.

Full description

Traditional images and graphics, like mathematical plots or charts, are not accessible to low vision and blind people. Instead, for blind and low vision people, tactile aids are traditionally used to convey abstract concepts. However, tactile aids cannot convey as rich or as dense of information as traditional visual graphics, limiting independence and access to gainful employment for low vision and blind professionals.

The primary reason why tactile aids are inferior to visual graphics is that tactile aids are made from a combination of physical bumps, lines, and labels. Placing too many details on a single tactile aid quickly becomes illegible to the user because the various bumps, lines, and textures blur together, which is known as "tactile clutter".

The objective of this project is to create richer tactile aids by using materials chemistry to create tactile sensations in tactile aids, as an alternative to traditional physical bumps, lines, or textures. These materials are commonly used in household products, but have not yet been used to enrich tactile aids. Successful outcomes include having low vision or blind subjects identify objects made from our tactile materials quicker than traditional tactile aids, or to successfully identify more categories on a mathematical plot than is currently possible with existing tactile aids.

Enrollment: 100 estimated patients

Sex: All

Ages: 16+ years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Visual Impairment: Participants should be blind or visually impaired for greater than 10 years, either congenitally or acquired.
• Tactile Aid Usage: Participants must use tactile aids regularly.
• Mathematical Knowledge: Participants should have a basic understanding of mathematical plots, equivalent to at least high school geometry.

Exclusion criteria

• Limb Conditions: Participants with amputations or outer extremity conditions affecting hand use will be excluded.

Trial design

Primary purpose: Basic Science

Allocation: Non-Randomized

Interventional model: Sequential Assignment

Masking: None (Open label)

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100 participants in 3 patient groups

Identifying and synthesizing high-contrast tactile materials without physical features

Experimental group

Description:

Beyond the few materials investigators previously identified, it is unknown which materials are useful for creating tactile sensations. Common material properties such as a friction coefficient or hydrophilicity are insufficiently detailed to accurately predict friction forces-the basis of tactile stimuli. The investigators will use expertise in connecting tactile sensations with chemical structure through mechanical testing, theory, and human testing. The investigators' goal is to identify materials that lead to high tactile contrast without relying on physical features. (Tactile contrast is defined by the investigators as large differences in friction which are easily distinguishable by humans during free tactile exploration.)

Treatment:

Behavioral: Optimal spacing between bumps

Behavioral: Single bump acuity

Behavioral: Improving signal from a single bump with designer materials

Building tactile aids with designer materials for plots, games, and object labeling

Experimental group

Description:

Investigators will build static tactile aids with designer materials, i.e., silanes and polymers coatings. These aids will be a mathematical plot, a board game, and simulated money. Investigators will compare the speed, accuracy, and amount of information of hybrid tactile aids made from designer materials and physical features to traditional tactile aids made only with bumps.

Treatment:

Behavioral: Optimal spacing between bumps

Behavioral: Single bump acuity

Behavioral: Improving signal from a single bump with designer materials

Optimal design of bumps and designer materials in tactile aids

Experimental group

Description:

Reflecting the lack of standardized methods or benchmarks for tactile technologies, the known limits of tactile sensitivity was narrowed from millimeters, microns, to nanometers within the last 10 years by use of metal wires, wrinkled plastics, and silanes, respectively. Investigators will determine the optimal design of traditional bumps which yields the highest tactile stimulus in the smallest area. Investigators expect to find that current bumps are larger than necessary, and that the same information could be placed into a smaller area (higher information density). Then, investigators will augment bumps with designer materials to increase the tactile stimulus from a bump, thereby permitting even smaller bumps to increase information density. Beyond optimal design methods, the investigators' quantitative methods, enabled by making the mechanical stimulus the dependent variable, also serve as benchmarks between tactile aids.

Treatment:

Behavioral: Optimal spacing between bumps

Behavioral: Single bump acuity

Behavioral: Improving signal from a single bump with designer materials