Disabled is a term used to describe people who have a physical or mental impairment that interferes with their ability to lead a happy, productive life. Physical impairments include blindness, deafness, deformity, muscular and nervous disorders, paralysis, and loss of limbs. There are two general kinds of mental impairments, mental illness and mental retardation.

An impairment may or may not be a disability. It becomes so if it interferes with a persons expectations, job performance, or relationships with his or her family, friends, and society in general. Individuals with similar impairments may not be equally disabled. For example, a history professor may not be greatly disabled by the loss of a finger. However, the same impairment would be a terrible disability to a concert pianist. People who have disabilities are sometimes referred to as handicapped.

There are about 35 million disabled people in the United States. Many common disabilities result from diseases. Heart disease may permanently decrease the victims strength and endurance. Strokes may produce paralysis and loss of speech. Arthritis and many bone diseases can lead to deformity. Certain nerve diseases may result in blindness, deafness, and lack of coordination. Cerebral palsy is a disorder that damages the brain before, during, or after birth. Depending on what part of the brain is damaged, cerebral palsy can cause speech problems, mental retardation, muscular weakness, or involuntary movements of the arms and legs. Accidents cause a wide range of disabilities, including spinal damage and loss of limbs.

With proper motivation and special training, people with severe disabilities can lead productive, fulfilling lives. Many famous people have overcome physical impairments to make major contributions to humanity. The English poet John Milton was blind when he wrote his epic masterpiece, Paradise Lost. The great German composer Ludwig van Beethoven wrote much of his finest music after he became deaf. The American inventor Thomas Edison, perhaps the greatest inventor in history, was deaf much of his life. Franklin D. Roosevelt, paralyzed in both legs by polio at the age of 39, became President of the United States. Helen Keller became blind, deaf, and mute before she was 2 years old, but she learned to read, write, and speak. She devoted her life to helping the deaf and the blind.