Amyotrophic lateral sclerosis overview
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Differentiating Amyotrophic lateral sclerosis from other Diseases |
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Amyotrophic Lateral Sclerosis is a progressive, usually fatal, neurodegenerative disease caused by the degeneration of motor neurons, the nerve cells in the central nervous system that control voluntary muscle movement. As a motor neuron disease, the disorder causes muscle weakness and atrophy throughout the body as both the upper and lower motor neurons degenerate, ceasing to send messages to muscles. Unable to function, the muscles gradually weaken, develop fasciculations (twitches) because of denervation, and eventually atrophy due to that denervation. The patient may ultimately lose the ability to initiate and control all voluntary movement except of the eyes.
Cognitive function is generally spared except in certain situations such as when ALS is associated with frontotemporal dementia.[1] However, there are reports of more subtle cognitive changes of the frontotemporal type in many patients when detailed neuropsychological testing is employed. Sensory nerves and the autonomic nervous system, which controls functions like sweating, generally remain functional.
Historical Perspective
The word amyotrophic is present Greek in origin. A means no or negative, myo refers to muscle, and trophic means nourishment. When put together it means "no-muscle-nourishment." Lateral identifies the areas of the spinal cord where portions of the nerve cells that signal and control the muscles are located. As this area degenerates it leads to scarring or hardening (sclerosis) in the region. [2]
Classification
ALS is classified into three general groups, familial ALS, sporadic ALS and Guamanian ALS.
References
- ↑ Phukan J, Pender NP, Hardiman O (2007). "Cognitive impairment in amyotrophic lateral sclerosis". Lancet Neurol. 6 (11): 994–1003. doi:10.1016/S1474-4422(07)70265-X. PMID 17945153.
- ↑ What is ALS - The ALS Association Retrieved October 24, 2006