1 Touch Response: The keys on a digital piano or keyboard can be weighted (similar to those of a traditional piano), touch sensitive (unweighted but still sound loud when struck hard), or neither.
In very rare instances, eyelid twitching can indicate a more serious condition, like the beginning stages of multiple sclerosis or a lesion on the brain stem. Those conditions typically begin with a host of symptoms, and in this circumstance the eyelid twitch soon moves to the facial muscles, as well.
The most common things that make the muscle in your eyelid twitch are fatigue, stress, and caffeine. Once spasms begin, they may continue off and on for a few days. Then, they disappear. Most people have this type of eyelid twitch once in a while and find it very annoying.