Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease (MND) or Lou Gehrigs disease, is a neurodegenerative disease that results in the progressive loss of motor neurons that control voluntary muscles. ALS is the most common type of motor neuron disease. Early symptoms of ALS include stiff muscles, muscle twitches, and gradual increasing weakness and muscle wasting. Limb-onset ALS begins with weakness in the arms or legs, while bulbar-onset ALS begins with difficulty speaking or swallowing. Half of the people with ALS develop at least mild difficulties with thinking and behavior, and about 15% develop frontotemporal dementia. Most people experience pain. The affected muscles are responsible for chewing food, speaking, and walking. Motor neuron loss continues until the ability to eat, speak, move, and finally the ability to breathe is lost. ALS eventually causes paralysis and early death, usually from respiratory failure.Most cases of ALS (about 90% to 95%) have no known cause, and are known as sporadic ALS. However, both genetic and environmental factors are believed to be involved. The remaining 5% to 10% of cases have a genetic cause linked to a history of the disease in the family, and these are known as familial ALS. About half of these genetic cases are due to one of two specific genes. ALS and frontotemporal dementia (FTD) are considered to be part of a common disease continuum (ALS-FTD) because of genetic, clinical, and pathological similarities.
In 1969 Edward H. Lambert published the first EMG/NCS diagnostic criteria for ALS, consisting of four findings he considered to strongly support the diagnosis. In 1990, the World Federation of Neurology (WFN) held a meeting at El Escorial, Spain, to come up with precise diagnostic criteria for ALS to help standardize clinical trials; the resulting "El Escorial" criteria were published in 1994. In 1998, the WFN held another meeting to revise the criteria at Airlie House in Warrenton, Virginia; the resulting "Airlie House" or "El Escorial Revised" criteria were published in 2000. In 2006, a meeting was held on Awaji Island in Japan to discuss how to use EMG and NCV tests to help diagnose ALS earlier; the resulting "Awaji" criteria were published in 2008. Name
Amyotrophic comes from Greek: a- means "no", myo- (from mûs) refers to "muscle", and trophḗ means "nourishment". Therefore, amyotrophy means "muscle malnourishment" or the wasting of muscle tissue. Lateral identifies the areas in a persons spinal cord where the affected motor neurons that control muscle are located. Sclerosis means "scarring" or "hardening" and refers to the death of the motor neurons in the spinal cord.ALS is sometimes referred to as Charcots disease (not to be confused with Charcot–Marie–Tooth disease and Charcot joint disease), because Jean-Martin Charcot was the first to connect the clinical symptoms with the pathology seen at autopsy.