This reminds of of a paper a read a couple years ago.

https://mdedge-files-live.s3.us-east-2.amazonaws.com/files/s...

There's also some recent papers on how the glymphatic system differs in people with iNPH

https://academic.oup.com/brain/article/140/10/2691/4085293

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6124518/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6609364/

I suspect some of what we see as singular disorders (Alzheimers, etc...) now will eventually be seen as sets of other distinct disorders.