HEALTH SCIENCE

Health Science

Health Science

What Is Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS)? sometimes called Lou Gehrig's disease? is a rapidly progressive? invariably fatal neurological disease that attacks the nerve cells (neurons) responsible for controlling voluntary muscles. The disease belongs to a group of disorders known as motor neuron diseases? which are characterized by the gradual degeneration and death of motor neurons. Motor neurons are nerve cells located in the brain? brainstem? and spinal cord that serve as controlling units and vital communication links between the nervous system and the voluntary muscles of the body. (Conwit? 2006 215-221) Messages from motor neurons in the brain (called upper motor neurons) are transmitted to motor neurons in the spinal cord (called lower motor neurons) and from them to particular muscles. In ALS? both the upper motor neurons and the lower motor neurons degenerate or die? ceasing to send messages to muscles. Unable to function? the muscles gradually weaken? waste away (atrophy)? and twitch (fasciculations). Eventually? the ability of the brain to start and control voluntary movement is lost. ALS causes weakness with a wide range of disabilities (see section titled "What are the symptoms?"). Eventually? all muscles under voluntary control are affected? and patients lose their strength and the ability to move their arms? legs? and body. When muscles in the diaphragm and chest wall fail? patients lose the ability to breathe without ventilatory support. (Conwit? 2006 215-221) Most people with ALS die from respiratory failure? usually within 3 to 5 years from the onset of symptoms. However? about 10 percent of ALS patients survive for 10 or more years.

Although the disease usually does not impair a person's mind or intelligence? several recent studies suggest that some ALS patients may have alterations in cognitive functions such as depression and problems with decision-making and memory. ALS does not affect a person's ability to see? smell? taste? hear? or recognize touch. Patients usually maintain control of eye muscles and bladder and bowel functions? although in the late stages of the disease most patients will need help getting to and from the bathroom. (Conwit? 2006 215-221)

What are the symptoms?

The onset of ALS may be so subtle that the symptoms are frequently overlooked. The earliest symptoms may include twitching? cramping? or stiffness of muscles; muscle weakness affecting an arm or a leg; slurred and nasal speech; or difficulty chewing or swallowing. These general complaints then develop into more obvious weakness or atrophy that may cause a physician to suspect ALS. (Xia X? Zhou? 2006? 23)

The parts of the body affected by early symptoms of ALS depend on which muscles in the body are damaged first. In some cases? symptoms initially affect one of the legs? and patients experience awkwardness when walking or running or they notice that they are tripping or stumbling more often. Some patients first see the effects of the disease on a hand or arm as they experience difficulty with simple tasks requiring manual dexterity such as buttoning a shirt? writing? or turning a key in ...