Amyotrophic (uh-my-o-TROAF-ik) Lateral Sclerosis (scla-ROE-siss), or A-L-S, is a degenerative disease of the central nervous system that leads to a slow, progressive paralysis of the voluntary muscles.

A brain tumor is an abnormal growth in or on the brain. There are many different types of brain tumors; some are benign (bih-NINE), and some are malignant.

Epilepsy (ep-i-lep-see) is a brain disorder that results in seizures. The seizures occur when brain cells release too much electrical energy causing a sudden loss of control over movement, thought, and awareness.

The brain and spinal cord are covered by a fatty tissue called myelin (MY-ah-lin). Myelin protects nerve cell fibers, and allows electrical impulses to travel speedily between the brain, spinal cord, and the rest ofthe body.

Parkinson's disease, sometimes called 'shaking palsy,' occurs when the nerve centers in the brain that control movement begin to deteriorate. In particular, you lose the brain cells that produce dopamine (DOPE-uh-meen), a chemical that regulates the movement of muscles.

A stroke is an interruption of blood flow to the brain, causing the affected area of the brain to die. It can occur when an artery serving the brain ruptures, or is plugged by a blood clot.

Alzheimer's (ALLS-hi-mers) disease is a progressive, degenerative disease that attacks the brain and results in impaired memory, thinking, and reasoning.