ALS and twitching

Although muscle weakness is the most common symptom associated with early stages of ALS, another sign is fleeting twitches of the muscles under the skin. In almost all cases of ALS, twitching comes after muscle weakness.

There are many causes for twitches (or fasciculations), but in ALS cases they are seen as a sign of motor neuron disease. As communication begins to break down between the brain and the rest of the body, stray impulses cause muscle twitching in ALS patients. Lower motor neuron degeneration can cause fleeting twitches that can be seen beneath the surface of the skin.

Patients must have signs and symptoms of both upper and lower motor neuron damage that cannot be attributed to other causes in order to be diagnosed with ALS (see ALS Diagnosis).