"Filtering the Evidence: Is There a Cognitive Cost of Hemodialysis?" (https://jasn.asnjournals.org/content/29/4/1087) reviews recent research and finds cognitive impairment both significant and prevalent as a side effect of in-center hemodialysis (as opposed to peritoneal dialysis, which is less harmful). It cites among other things an RCT result entitled "Cognitive impairment in hemodialysis patients is common" (https://pubmed.ncbi.nlm.nih.gov/16864811/), which is frequently cited in studies and articles reviewing this phenomenon; the "Cited by" list on that page is a fertile ground for further review.

Dirty blood is toxic to many organs. The ears, eyes, and nose will all degrade along with the mind as kidneys fail. The worst is that dirty blood is toxic to the kidneys, so failing kidneys cause kidney failure.