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.
In its most common form, eye twitching is harmless and stops on its own, although it may recur occasionally. Sometimes, eye twitching may be the earliest sign of a chronic movement disorder, especially if other facial spasms develop in addition to the eye twitching. Usually, however, there is no identifiable cause. Some of the causes of eyelid spasms that have been identified include: 1  Alcohol intake. 2  Bright lights.