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.
An eye twitch is an involuntary, abnormal blinking of your eyelid. This abnormal blinking may happen many times per day. If eye twitching is severe, it can impair vision. The orbicularis oculi is a muscle of the face that closes your eyelid.