aphasia vs encephalopathy

aphasia and encephalopathy both are nouns.

Word	Noun	Adjective	Verb	Adverb
aphasia	Yes	No	No	No
encephalopathy	Yes	No	No	No

As nouns, encephalopathy is a hypernym of aphasia; that is, encephalopathy is a word with a broader meaning than aphasia:

aphasia: inability to use or understand language (spoken or written) because of a brain lesion
encephalopathy: any disorder or disease of the brain

Other hypernyms of aphasia include brain disease, brain disorder.

aphasia (noun)	encephalopathy (noun)
inability to use or understand language (spoken or written) because of a brain lesion	any disorder or disease of the brain