Nervous System Disease

The brain and nervous system are interconnected systems which facilitate communication within the body and between the body and the outside world. Diseases that affect the brain and nervous system, collectively called neurological diseases, range from relatively common to extremely rare. The most frequent neurological diseases include stroke, Parkinson’s disease, Alzheimer’s and Huntington’s disease, multiple sclerosis, motor neuron disease, epilepsy, and migraine. Brain or nervous system diseases affect the structure and functioning of the brain, the spinal cord, and the peripheral nerves. They can affect cognition, physical movement, emotional behavior, or any combination of these. There are a wide variety of causes of brain and nervous system disease, including injury, genetics, and infection. Certain environmental factors, such as poor nutrition, toxin exposure, and alcohol abuse, can also increase the risk of developing neurological disease. Stroke, which is caused by a disruption in the supply of blood to the brain, is the leading cause of disability in adults in the United States. Symptoms of stroke, which can occur in both men and women, include a sudden onset of numbness or weakness, a sudden trouble speaking or understanding language, the inability to move a part of the body, and facial drooping. Parkinson’s disease is a chronic neurodegenerative movement disorder that is caused by the progressive loss of dopamine-producing neurons in the brain. Symptoms typically appear in middle age and include trembling, stiffness, loss of balance, and difficulty walking and speaking. Alzheimer's disease, a form of dementia, is an irreversible and progressive brain disorder which eventually leads to memory loss, confusion, and difficulty in performing activities of daily life. It affects as many as 5.7 million people in the United States and is the sixth leading cause of death. Huntington’s disease is another rarely inherited neurological disorder that affects movement and cognition. It is caused by a mutation of a single gene on chromosome 4 and is characterized by jerky movements, muscle spasms, slower and halting movements, and gradual intellectual decline. Multiple sclerosis is a progressive disease of the central nervous system which affects the myelin sheath that surrounds the nerves.