To give you an idea of how common fasciculations are, they have been described as being present in about 80% of normal people undergoing an electromyogram (EMG), those these are noticed by the person themselves only about 50% of the time.
Because fasciculations can be intensely annoying and disruptive, people are often curious about the cause and whether they can be offered any relief. Those who search online for an explanation may become frightened by some of the serious diseases that can cause this common symptom.
For example, a quick Google search for “what causes fasciculations” almost immediately mentions amyotrophic lateral sclerosis (ALS), a neurological illness that slowly robs people of their ability to move.
It’s important to remember that diseases like ALS are relatively uncommon—a fasciculation is more likely to be unrelated to anything so devastating. For example, many of us develop fasciculations when we have had too little sleep, too much coffee, or a wide number of medications running from diphenhydramine to pseudoephedrine.
A study of 121 patients with a diagnosis of benign fasciculations followed those patients for up to 32 years. None of those patients developed any serious motor neuron disease such as ALS. About half said their symptoms had improved.