hyperacusia vs hyperacusis

hyperacusia and hyperacusis both are nouns.

Word	Noun	Adjective	Verb	Adverb
hyperacusia	Yes	No	No	No
hyperacusis	Yes	No	No	No

As nouns, hyperacusia and hyperacusis are synonyms defined as:

hyperacusia and hyperacusis: abnormal acuteness of hearing due to increased irritability of the sensory neural mechanism; characterized by intolerance for ordinary sound levels

Other synonyms of hyperacusia include auditory hyperesthesia.

hyperacusia (noun)	hyperacusis (noun)
abnormal acuteness of hearing due to increased irritability of the sensory neural mechanism; characterized by intolerance for ordinary sound levels	abnormal acuteness of hearing due to increased irritability of the sensory neural mechanism; characterized by intolerance for ordinary sound levels