Difficulties and disabilities can be obvious or hidden. The federal government explains this as follows: While “a disability such as a limp, paralysis, total blindness or deafness is usually obvious to others. But hidden disabilities such as low vision, poor hearing, heart disease, or chronic illness may not be obvious. A chronic illness involves a recurring and long-term disability such as diabetes, heart disease, kidney and liver disease, high blood pressure, or ulcers.
“Hidden” disabilities are defined as those that “are physical or mental impairments that are not readily apparent to others. They include such conditions and diseases as:
• specific learning disabilities
“Approximately four million students with disabilities are enrolled in public elementary and secondary schools in the United States. Of these 43 percent are students classified as learning disabled, 8 percent as emotionally disturbed, and 1 percent as other health impaired. These hidden disabilities often cannot be readily known without the administration of appropriate diagnostic tests.”