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.
Common symptoms of twitching of eyelid are: 1  Repeated uncontrollable twitching or spasms of your eyelid (most often the upper lid) 2  Light sensitivity (sometimes, this is the cause of the twitching) 3  Blurry vision (sometimes)