fasciculation vs twitching

fasciculation and twitching both are nouns.

Word	Noun	Adjective	Verb	Adverb
fasciculation	Yes	No	No	No
twitching	Yes	No	No	No

As nouns, twitching is a hypernym of fasciculation; that is, twitching is a word with a broader meaning than fasciculation:

fasciculation: muscular twitching of contiguous groups of muscle fibers
twitching: a sudden muscle spasm; especially one caused by a nervous condition

Other hypernyms of fasciculation include twitch, vellication.

fasciculation (noun)	twitching (noun)
muscular twitching of contiguous groups of muscle fibers	a sudden muscle spasm; especially one caused by a nervous condition