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.