Originally Posted by
livedarklions
I suspected something may have changed which is why I specified how long ago this coursework was. They don't just happen after damage, do they? Most of them are so transient that it doesn't seem like any sort of structural cause would be likely.
As noted, they are normal in the gastroc-soleus and, rarely, throughout the body in the syndrome of benign fasciculation. However, they are the hallmark of motor nerve damage from trauma, disc herniation, rapidly progressive neuropathies, etc. When they occur "out of the blue" everyone's first thought is amyotrophic lateral sclerosis.