What is ALS?
Amyotrophic lateral sclerosis (ALS), commonly known as Lou Gehrig’s disease, is a progressive neuromuscular disease characterized by a progressive deterioration of upper motor neurons (in the brain cortex) and lower motor neurons (in the brainstem and spinal cord). When the motor neurons can no longer send impulses to the muscles, the muscles begin to waste away (atrophy), causing increased muscle weakness.
Here are some terms that are often associated with ALS:
Brisk Reflex: A condition that describes the deterioration of the upper motor nerve cells (neurons).
Bulbar Muscles: The muscles that control the speech, chewing and swallowing.
Classical ALS: A progressive neurological disease characterized by a deterioration of upper and lower motor nerve cells (neurons). This type of ALS affects over two-thirds of all people with ALS.
Dysarthria: Impaired speech and language due to weakness or stiffness in the muscles used for speaking.
Dysphagia: Impaired chewing and swallowing.
Exertional Dyspnea: A condition characterized by shortness of breath during physical activity.
Familial ALS (or FALS): A progressive neurological disease that affects more than one member of the same family. This type of ALS accounts for a very small number of people with ALS in the United States (5–10%).
Fasciculations: Non-painful, rapid and involuntary contractions or twitchings of groups of muscle fibers. This is often described by people with ALS as “a persistent rolling beneath the skin.”
Flaccid, Weak Muscles (also Hypotonicity): A condition characterized by a decrease or loss of normal muscle tone due to the deterioration of the lower motor nerve cells.
Hyperreflexia: Excessive response of muscle reflexes when a normal stimulus is applied.
Hyporeflexia: Weak or absent muscle response when a normal stimulus is applied.
Lower Motor Neurons: Nerve cells (neurons) situated in the spinal cord and brain stem and their projections (axons) forming nerves that end in the muscle fibers.
Motor Neuron Diseases: A group of disorders in which motor nerve cells (neurons) in the spinal cord and brain stem deteriorate and die. ALS is the most common motor neuron disease.
Muscle Atrophy: Loss of muscle fiber volume characterized by a visible decrease in muscle size. This occurs because muscles no longer receive impulses, or "messages," from nerve cells (neurons).
Muscle Cramps, Unexpected: Involuntary, painful shortening of muscles. Usually, a knotting of the muscles is visible.
Muscle Weakness: Loss of strength, increased fatigue, loss of coordination and difficulty with motor skills and lack of ability to carry out certain skills.
Primary Lateral Sclerosis (PLS): A progressive neurological disease in which the upper motor nerve cells(neurons) deteriorate. If the lower motor neurons are not affected two years, the disease usually remains a pure upper motor neuron disease. This is the rarest of all forms of ALS.
Progressive Bulbar Palsy (PBP): A condition that starts with difficulties speaking, chewing and swallowing due to lower motor nerve cell (neuron) deterioration. This disorder affects about 25% of all people with ALS.
Progressive Muscular Atrophy (PMA): A progressive neurological disease in which the lower motor nerve cells (neurons) deteriorate. If the upper motor neurons are not affected within two years, the disease usually remains a pure lower motor neuron disease.
Pseudobulbar Palsy: A condition that is characterized by difficulties with speech, chewing and swallowing. These symptoms resemble those of bulbar palsy, but this condition is also characterized by spontaneous or unmotivated crying and laughing.
Sialorrhea: Drooling resulting from the lack of spontaneous, automatic swallowing to clear excessive saliva in the mouth.
SOD1 positive FALS: The copper-zinc SOD (SOD1) is the first gene found to have mutations resulting in approximately 20% of FALS, or approximately 1 – 2% of all ALS.
Spasticity: A state of increased muscle tension when the muscle is lengthened. Often involves an exaggeration of the tendon reflexes.
Spinal Muscular Atrophy (SMA): A hereditary neurological disease in which only the lower motor nerve cells are affected.
Upper Motor Neurons: Nerve cells (neurons) originating in the brain’s motor cortex and their projections (axons) descending through the brainstem and spinal cord.